D30.06 - Interlaminar Properties

SIGNIFICANCE AND USE
5.1 This test method is designed to produce through-thickness failure data for structural design and analysis, quality assurance, and research and development. Factors that influence the through-thickness tensile strength, and should therefore be reported, include the following: material and fabric reinforcement, methods of material and fabric preparation, methods of processing and specimen fabrication, specimen stacking sequence, specimen conditioning, environment of testing, specimen alignment, speed of testing, time at temperature, void content, and volume reinforcement content.
SCOPE
1.1 This test method determines the through-thickness “flatwise” tensile strength and elastic modulus of fiber reinforced polymer matrix composite materials. A tensile force is applied normal to the plane of the composite laminate using adhesively bonded thick metal end-tabs. The composite material forms are limited to continuous fiber (unidirectional reinforcement or two-dimensional fabric) or discontinuous fiber (nonwoven or chopped) reinforced composites.  
1.2 The through-thickness strength results using this test method will in general not be comparable to Test Method D6415 since this method subjects a relatively large volume of material to an almost uniform stress field while Test Method D6415 subjects a small volume of material to a non-uniform stress field.  
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3.1 Within the text, the inch-pound units are shown in brackets.  
1.4 This standard may involve hazardous materials, operations, and equipment.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of the interlaminar fracture resistance of composites is useful for product development and material selection. Since delaminations can be subjected to and extended by loadings with a wide range of mode mixtures, it is important that the composite toughness be measured at various mode mixtures. The toughness contour, in which fracture toughness is plotted as a function of mode mixtures (see Fig. 3), is useful for establishing failure criterion used in damage tolerance analyses of composite structures made from these materials.
FIG. 3 Mixed-Mode Summary Graph  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on Gc of a particular composite material at various mode mixtures,  
5.2.2 To compare quantitatively the relative values of Gc versus mode mixture for composite materials with different constituents, and  
5.2.3 To develop delamination failure criteria for composite damage tolerance and durability analyses.  
5.3 This method can be used to determine the following delamination toughness values:  
5.3.1 Delamination Initiation—Two values of delamination initiation shall be reported: (1) at the point of deviation from linearity in the load-displacement curve (NL) and (2) at the point at which the compliance has increased by 5 % or the load has reached a maximum value (5%/max) depending on which occurs first along the load deflection curve (see Fig. 4). Each definition of delamination initiation is associated with its own value of Gc and  GII/G calculated from the load at the corresponding critical point. The 5%/Max  Gc value is typically the most reproducible of the three Gc values. The NL value is, however, the more conservative number. When the option of collecting ...
SCOPE
1.1 This test method covers the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section 6). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.  
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major design concerns for many advanced laminated composite structures. Complex structural geometries can result in out-of-plane stresses, which may be difficult to analyze. When curved structural details are loaded such that the deformation results in an increase in the radius of curvature, interlaminar tensile stress and delaminations can result. Knowledge of a laminated composite material’s resistance to interlaminar fracture is useful for product development and material selection. Failure criteria and design allowables involving out-of-plane stresses may not be readily available or may be poorly validated, requiring additional experimental data.  
5.2 This test method can serve the following purposes:  
5.2.1 To measure a curved-beam strength;  
5.2.2 To measure an interlaminar strength when using a unidirectional specimen where all fibers are oriented 0° relative to the long straight edges of the specimen;  
5.2.3 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on the curved beam strength or the interlaminar (through-the-thickness) tensile strength of a particular composite material;  
5.2.4 To compare quantitatively the relative curved-beam strength or interlaminar tensile strengths of composite materials with different constituents;  
5.2.5 To compare quantitatively the values of the curved-beam strength or interlaminar tensile strengths obtained from different batches of a specific composite material, for example, to use as a material screening criterion, to use for quality assurance, or to develop a design allowable;  
5.2.6 To produce out-of-plane structural failure data for structural design and analysis; and  
5.2.7 To develop failure criteria for predicting failures caused by out-of-plane stresses.
SCOPE
1.1 This test method determines the curved beam strength of a continuous fiber-reinforced composite material using a 90° curved beam specimen (Figs. 1 and 2). The curved beam consists of two straight legs connected by a 90° bend with a 6.4 mm [0.25 in.] inner radius. An out-of-plane (through-the-thickness) tensile stress is produced in the curved region of the specimen when force is applied. This test method is limited to use with composites consisting of layers of fabric or layers of unidirectional fibers.
FIG. 1 Test Specimen Geometry (SI units)  
FIG. 2 Test Specimen Geometry (inch-pound)  
1.2 This test method may also be used to measure the interlaminar tensile strength if a unidirectional specimen is used where the fibers run continuously along the legs and around the bend.  
1.3 This test method is limited to use with composites consisting of layers of fabric or layers of unidirectional fibers.  
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.4.1 Within the text, the inch-pound units are shown in brackets.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major design concerns for many advanced laminated composite structures. Knowledge of a laminated composite material's resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the mode I interlaminar fracture toughness that is independent of specimen geometry or method of force introduction is useful for establishing design allowables used in damage tolerance analyses of composite structures. Knowledge of both the non-precracked and precracked toughness allows the appropriate value to be used for the application of interest.  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIc of a particular composite material;  
5.2.2 To compare quantitatively the relative values of GIc for composite materials with different constituents;  
5.2.3 To compare quantitatively the values of GIc obtained from different batches of a specific composite material, for example, to use as a material screening criterion or to develop a design allowable; and  
5.2.4 To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the opening mode-I interlaminar fracture toughness,  GIc, of unidirectional fiber-reinforced polymer matrix composite laminates using the double cantilever beam (DCB) specimen (Fig. 1).  
FIG. 1 Double Cantilever Beam Specimen  
1.2 This test method is limited to use with composites consisting of unidirectional carbon-fiber and glass-fiber-reinforced laminates with brittle or tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.6).  
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3.1 Within the text, the inch-pound units are shown in brackets.  
1.4 This standard may involve hazardous materials, operations, and equipment.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major design concerns for many advanced laminated composite structures. Knowledge of a laminated composite material’s resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the mode II interlaminar fracture toughness that is independent of specimen geometry or method of force introduction is useful for establishing design allowables used in damage tolerance analyses of composite structures. Knowledge of both the non-precracked and precracked toughnesses allows the appropriate value to be used for the application of interest.  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIIc of a particular composite material;  
5.2.2 To compare quantitatively the relative values of GIIc for composite materials with different constituents;  
5.2.3 To compare quantitatively the values of GIIc obtained from different batches of a specific composite material, for example, to use as a material screening criterion or to develop a design allowable; and  
5.2.4 To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method covers the determination of the mode II interlaminar fracture toughness, GIIc, of unidirectional fiber-reinforced polymer matrix composite laminates under mode II shear loading using the end-notched flexure (ENF) test (Fig. 1).
FIG. 1 ENF Test Fixture and Specimen Nomenclature  
1.2 This method is limited to use with composites consisting of unidirectional carbon-fiber- and glass-fiber-reinforced laminates. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see Section 6).  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3.1 Within the text the inch-pound units are shown in brackets.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material's resistance to interlaminar fracture under fatigue loads is useful for product development and material selection. Furthermore, a measurement of the relationship of the mode I cyclic strain energy release rate and the number of cycles to delamination growth onset, G–N, that is independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on G–N  of a particular composite material.  
5.2.2 To compare quantitatively the relative values of G–N  for composite materials with different constituents.  
5.2.3 To develop criteria for avoiding the onset of delamination growth under fatigue loading for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method determines the number of cycles (N) for the onset of delamination growth based on the opening mode I cyclic strain energy release rate (G), using the Double Cantilever Beam (DCB) specimen shown in Fig. 1. This test method applies to constant amplitude, tension-tension fatigue loading of continuous fiber-reinforced composite materials. When this test method is applied to multiple specimens at various G-levels, the results may be shown as a G–N  curve, as illustrated in Fig. 2.
FIG. 1 DCB Specimen with Piano Hinges  
FIG. 2  G–N Curve  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with single-phase polymer matrices. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials, however, certain interferences have been noted (see Section 6.5 of Test Method D5528).  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3.1 Exception—The values provided in parentheses are for information only.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of the interlaminar fracture resistance of composites is useful for product development and material selection. Since delaminations can be subjected to and extended by loadings with a wide range of mode mixtures, it is important that the composite toughness be measured at various mode mixtures. The toughness contour, in which fracture toughness is plotted as a function of mode mixtures (see Fig. 3), is useful for establishing failure criterion used in damage tolerance analyses of composite structures made from these materials.
FIG. 3 Mixed-Mode Summary Graph  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on Gc of a particular composite material at various mode mixtures,  
5.2.2 To compare quantitatively the relative values of Gc versus mode mixture for composite materials with different constituents, and  
5.2.3 To develop delamination failure criteria for composite damage tolerance and durability analyses.  
5.3 This method can be used to determine the following delamination toughness values:  
5.3.1 Delamination Initiation—Two values of delamination initiation shall be reported: (1) at the point of deviation from linearity in the load-displacement curve (NL) and (2) at the point at which the compliance has increased by 5 % or the load has reached a maximum value (5%/max) depending on which occurs first along the load deflection curve (see Fig. 4). Each definition of delamination initiation is associated with its own value of Gc and  GII/G calculated from the load at the corresponding critical point. The 5%/Max  Gc value is typically the most reproducible of the three Gc values. The NL value is, however, the more conservative number. When the option of collecting ...
SCOPE
1.1 This test method covers the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section 6). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major design concerns for many advanced laminated composite structures. Knowledge of a laminated composite material’s resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the mode II interlaminar fracture toughness that is independent of specimen geometry or method of force introduction is useful for establishing design allowables used in damage tolerance analyses of composite structures. Knowledge of both the non-precracked and precracked toughnesses allows the appropriate value to be used for the application of interest.  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIIc of a particular composite material;  
5.2.2 To compare quantitatively the relative values of GIIc for composite materials with different constituents;  
5.2.3 To compare quantitatively the values of GIIc obtained from different batches of a specific composite material, for example, to use as a material screening criterion or to develop a design allowable; and  
5.2.4 To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method covers the determination of the mode II interlaminar fracture toughness, GIIc, of unidirectional fiber-reinforced polymer matrix composite laminates under mode II shear loading using the end-notched flexure (ENF) test (Fig. 1).
FIG. 1 ENF Test Fixture and Specimen Nomenclature  
1.2 This method is limited to use with composites consisting of unidirectional carbon-fiber- and glass-fiber-reinforced laminates. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see Section 6).  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3.1 Within the text the inch-pound units are shown in brackets.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is designed to produce through-thickness failure data for structural design and analysis, quality assurance, and research and development. Factors that influence the through-thickness tensile strength, and should therefore be reported, include the following: material and fabric reinforcement, methods of material and fabric preparation, methods of processing and specimen fabrication, specimen stacking sequence, specimen conditioning, environment of testing, specimen alignment, speed of testing, time at temperature, void content, and volume reinforcement content.
SCOPE
1.1 This test method determines the through-thickness “flatwise” tension strength and elastic modulus of fiber reinforced polymer matrix composite materials. A tensile force is applied normal to the plane of the composite laminate using adhesively bonded thick metal end-tabs. The composite material forms are limited to continuous-fiber or discontinuous fiber (tape or 2-dimensional fabric, or both) reinforced composites.  
1.2 The through-thickness strength results using this test method will in general not be comparable to Test Method D6415 since this method subjects a relatively large volume of material to an almost uniform stress field while Test Method D6415 subjects a small volume of material to a non-uniform stress field.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.  
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major design concerns for many advanced laminated composite structures. Knowledge of a laminated composite material’s resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the mode II interlaminar fracture toughness that is independent of specimen geometry or method of force introduction is useful for establishing design allowables used in damage tolerance analyses of composite structures. Knowledge of both the non-precracked and precracked toughnesses allows the appropriate value to be used for the application of interest.  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIIc of a particular composite material;  
5.2.2 To compare quantitatively the relative values of GIIc for composite materials with different constituents;  
5.2.3 To compare quantitatively the values of GIIc obtained from different batches of a specific composite material, for example, to use as a material screening criterion or to develop a design allowable; and  
5.2.4 To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the mode II interlaminar fracture toughness, GIIc, of unidirectional fiber-reinforced polymer matrix composite laminates under mode II shear loading using the end-notched flexure (ENF) test (Fig. 1).  
1.2 This method is limited to use with composites consisting of unidirectional carbon-fiber- and glass-fiber-reinforced laminates. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see Section 6).  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3.1 Within the text the inch-pound units are shown in brackets.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of the interlaminar fracture resistance of composites is useful for product development and material selection. Since delaminations can be subjected to and extended by loadings with a wide range of mode mixtures, it is important that the composite toughness be measured at various mode mixtures. The toughness contour, in which fracture toughness is plotted as a function of mode mixtures (see Fig. 3), is useful for establishing failure criterion used in damage tolerance analyses of composite structures made from these materials.  
5.3.2 Propagation Option—In the MMB test, the delamination will grow from the insert in either a stable or an unstable manner depending on the mode mixture being tested. As an option, propagation toughness values may be collected when delaminations grow in a stable manner. Propagation toughness values are not attainable when the delamination grows in an unstable manner. Propagation toughness values may be heavily influenced by fiber bridging which is an artifact of the zero-degree-type test specimen (3-5). Since they are often believed to be artificial, propagation values must be clearly marked as such when they are reported. One use of propagation values is to check for problems with the delamination insert. Normally, delamination toughness values rise from the initiation values as the delamination propagates and fiber bridging develops. When toughness values decrease as the delamination grows, a poor delamination insert is often the cause. The delamination may be too thick or deformed in such a way that a resin pocket forms at the end of the insert. For accurate initiation values, a properly implanted and inspected delamination insert is critical (see 8.2).  
5.3.3 Precracked Toughness—Under rare circumstances, toughness may decrease from the initiation values as the delamination propagates (see 5.3.2). If this oc...
SCOPE
1.1 This test method describes the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section 6). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Out-of-plane stress analyses are not easily performed. Failure criteria are varied and poorly validated. Interlaminar allowables are not readily available. However, stress analysts routinely encounter structural details in which they cannot ignore the out-of-plane loads. This test method is designed to produce out-of-plane structural failure data for structural design and analysis, quality assurance, and research and development. For unidirectional specimens, this test method is designed to produce interlaminar tensile strength data. Factors that influence the curved beam strength and should therefore be reported include the following: material, methods of material preparation, methods of processing and specimen fabrication, specimen preparation, specimen conditioning, environment of testing, speed of testing, time at temperature, void content, and volume percent reinforcement.
SCOPE
1.1 This test method determines the curved beam strength of a continuous fiber-reinforced composite material using a 90° curved beam specimen (Fig. 1 and Fig. 2). The curved beam consists of two straight legs connected by a 90° bend with a 6.4-mm [0.25 in.] inner radius. An out-of-plane (through-the-thickness) tensile stress is produced in the curved region of the specimen when force is applied. This test method is limited to use with composites consisting of layers of fabric or layers of unidirectional fibers.
1.2 This test method may also be used to measure the interlaminar tensile strength if a unidirectional specimen is used where the fibers run continuously along the legs and around the bend.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material's resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the Mode I interlaminar fracture toughness, independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.  
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on G Ic of a particular composite material.  
5.2.2 To compare quantitatively the relative values of GIc for composite materials with different constituents.  
5.2.3 To compare quantitatively the values of GIc obtained from different batches of a specific composite material, for example, to use as a material screening criterion or to develop a design allowable.  
5.2.4 To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness,  GIc, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig. 1).  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 This standard may involve hazardous materials, operations, and equipment.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of the interlaminar fracture resistance of composites is useful for product development and material selection. Since delaminations can be subjected to and extended by loadings with a wide range of mode mixtures, it is important that the composite toughness be measured at various mode mixtures. The toughness contour, in which fracture toughness is plotted as a function of mode mixtures (see Fig. 3), is useful for establishing failure criterion used in damage tolerance analyses of composite structures made from these materials.
5.2 This test method can serve the following purposes:  
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on Gc of a particular composite material at various mode mixtures,  
5.2.2 To compare quantitatively the relative values of Gc versus mode mixture for composite materials with different constituents, and  
5.2.3 To develop delamination failure criteria for composite damage tolerance and durability analyses.  
5.3 This method can be used to determine the following delamination toughness values:  
5.3.1 Delamination Initiation—Two values of delamination initiation shall be reported: (1) at the point of deviation from linearity in the load-displacement curve (NL) and (2) at the point at which the compliance has increased by 5 % or the load has reached a maximum value (5 %/max) depending on which occurs first along the load deflection curve (see Fig. 4). Each definition of delamination initiation is associated with its own value of Gc and  GII/G calculated from the load at the corresponding critical point. The 5 %/Max  Gc value is typically the most reproducible of the three Gc values. The NL value is, however, the more conservative number. When the option of collecting propagation values is taken (see 5...
SCOPE
1.1 This test method describes the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section 6). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material’resistance to interlaminar fracture under fatigue loads is useful for product development and material selection. Furthermore, a measurement of the relationship of the mode I cyclic strain energy release rate and the number of cycles to delamination growth onset, G–N, that is independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on G–N  of a particular composite material.
5.2.2 To compare quantitatively the relative values of G–N  for composite materials with different constituents.
5.2.3 To develop criteria for avoiding the onset of delamination growth under fatigue loading for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method determines the number of cycles (N) for the onset of delamination growth based on the opening mode I cyclic strain energy release rate (G), using the Double Cantilever Beam (DCB) specimen shown in . This test method applies to constant amplitude, tension-tension fatigue loading of continuous fiber-reinforced composite materials. When this test method is applied to multiple specimens at various G-levels, the results may be shown as a G-N  curve, as illustrated in Fig 2.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with single-phase polymer matrices. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials, however, certain interferences have been noted (see Section 6.5 of Test Method D 5528).
1.3 The values stated in SI units are to be regarded as standard. The values provided in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material's resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the Mode I interlaminar fracture toughness, independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIc of a particular composite material.
To compare quantitatively the relative values of GIc for composite materials with different constituents.
To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness, GIc, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig. 1).  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 This standard may involve hazardous materials, operations, and equipment.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material’resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the Mode I interlaminar fracture toughness, independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
5.2.1 To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIc of a particular composite material.
5.2.2 To compare quantitatively the relative values of GIc for composite materials with different constituents.
5.2.3 To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness, G Ic, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig 1).
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard may involve hazardous materials, operations, and equipment.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material's resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the Mode I interlaminar fracture toughness, independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIc of a particular composite material.
To compare quantitatively the relative values of GIc for composite materials with different constituents.
To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness, GIc, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig. 1).  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 This standard may involve hazardous materials, operations, and equipment.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material's resistance to interlaminar fracture is useful for product development and material selection. Furthermore, a measurement of the Mode I interlaminar fracture toughness, independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
To establish quantitatively the effect of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on GIc of a particular composite material.
To compare quantitatively the relative values of GIc for composite materials with different constituents.
To develop delamination failure criteria for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness, GIc, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig. 1).  
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 This standard may involve hazardous materials, operations, and equipment.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
(a) with piano hinges (b) with loading blocksFIG. 1 Double Cantilever Beam Specimen

SIGNIFICANCE AND USE
This test method is designed to produce through-thickness failure data for structural design and analysis, quality assurance, and research and development. Factors that influence the through-thickness tensile strength, and should therefore be reported, include the following: material and fabric reinforcement, methods of material and fabric preparation, methods of processing and specimen fabrication, specimen stacking sequence, specimen conditioning, environment of testing, specimen alignment, speed of testing, time at temperature, void content, and volume reinforcement content.
SCOPE
1.1 This test method determines the through-thickness "flatwise" tension strength and elastic modulus of fiber reinforced polymer matrix composite materials. A tensile force is applied normal to the plane of the composite laminate using adhesively bonded thick metal end-tabs. The composite material forms are limited to continuous-fiber or discontinuous fiber (tape or 2-dimensional fabric, or both) reinforced composites.
1.2 The through-thickness strength results using this test method will in general not be comparable to Test Method D 6415 since this method subjects a relatively large volume of material to an almost uniform stress field while Test Method D 6415 subjects a small volume of material to a non-uniform stress field.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

SIGNIFICANCE AND USE
Out-of-plane stress analyses are not easily performed. Failure criteria are varied and poorly validated. Interlaminar allowables are not readily available. However, stress analysts routinely encounter structural details in which they cannot ignore the out-of-plane loads. This test method is designed to produce out-of-plane structural failure data for structural design and analysis, quality assurance, and research and development. For unidirectional specimens, this test method is designed to produce interlaminar tensile strength data. Factors that influence the curved beam strength and should therefore be reported include the following: material, methods of material preparation, methods of processing and specimen fabrication, specimen preparation, specimen conditioning, environment of testing, speed of testing, time at temperature, void content, and volume percent reinforcement.
SCOPE
1.1 This test method determines the curved beam strength of a continuous fiber-reinforced composite material using a 90 curved beam specimen (Fig. 1 and Fig. 2). The curved beam consists of two straight legs connected by a 90 bend with a 6.4-mm [0.25 in.] inner radius. An out-of-plane (through-the-thickness) tensile stress is produced in the curved region of the specimen when force is applied. This test method is limited to use with composites consisting of layers of fabric or layers of unidirectional fibers.
1.2 This test method may also be used to measure the interlaminar tensile strength if a unidirectional specimen is used where the fibers run continuously along the legs and around the bend.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

SCOPE
1.1 This test method describes the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section ). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SCOPE
1.1 This test method determines the curved beam strength of a continuous fiber-reinforced composite material using a 90 curved beam specimen (Fig 1 and Fig 2). The curved beam consists of two straight legs connected by a 90 bend with a 6.4-mm [0.25 mm] inner radius. An out-of-plane (through-the-thickness) tensile stress is produced in the curved region of the specimen when force is applied. This test method is limited to use with composites consisting of layers of fabric or layers of unidirectional fibers.
1.2 This test method may also be used to measure the interlaminar tensile strength if a unidirectional specimen is used where the fibers run continuously along the legs and around the bend.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

SCOPE
1.1 This test method describes the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section ). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of a laminated composite material’resistance to interlaminar fracture under fatigue loads is useful for product development and material selection. Furthermore, a measurement of the relationship of the mode I cyclic strain energy release rate and the number of cycles to delamination growth onset, G–N, that is independent of specimen geometry or method of load introduction, is useful for establishing design allowables used in damage tolerance analyses of composite structures made from these materials.
This test method can serve the following purposes:
5.2.1 To establish quantitatively the effects of fiber surface treatment, local variations in fiber volume fraction, and processing and environmental variables on G–N  of a particular composite material.
5.2.2 To compare quantitatively the relative values of G–N  for composite materials with different constituents.
5.2.3 To develop criteria for avoiding the onset of delamination growth under fatigue loading for composite damage tolerance and durability analyses.
SCOPE
1.1 This test method determines the number of cycles (N) for the onset of delamination growth based on the opening mode I cyclic strain energy release rate (G), using the Double Cantilever Beam (DCB) specimen shown in . This test method applies to constant amplitude, tension-tension fatigue loading of continuous fiber-reinforced composite materials. When this test method is applied to multiple specimens at various G-levels, the results may be shown as a G-N  curve, as illustrated in Fig 2.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with single-phase polymer matrices. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials, however, certain interferences have been noted (see Section 6.5 of Test Method D 5528).
1.3 The values stated in SI units are to be regarded as standard. The values provided in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness, G Ic, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig. 1).
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard may involve hazardous materials, operations, and equipment.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SCOPE
1.1 This test method describes the determination of the opening Mode I interlaminar fracture toughness, G Ic, of continuous fiber-reinforced composite materials using the double cantilever beam (DCB) specimen (Fig. 1).
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber and glass fiber tape laminates with brittle and tough single-phase polymer matrices. This limited scope reflects the experience gained in round-robin testing. This test method may prove useful for other types and classes of composite materials; however, certain interferences have been noted (see 6.5).
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard may involve hazardous materials, operations, and equipment.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SCOPE
1.1 This test method describes the determination of interlaminar fracture toughness, Gc, of continuous fiber-reinforced composite materials at various Mode I to Mode II loading ratios using the Mixed-Mode Bending (MMB) Test.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices. This test is further limited to the determination of fracture toughness as it initiates from a delamination insert. This limited scope reflects the experience gained in round robin testing. This method may prove useful for other types of toughness values and for other classes of composite materials; however, certain interferences have been noted (see Section 6). This test method has been successfully used to test the toughness of both glass fiber composites and adhesive joints.
1.3 The values stated in SI units are to be regarded as standard. The values provided in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SCOPE
1.1 This test method determines the curved beam strength of a continous fiber-reinforced composite material using a 90o curved beam specimen (Fig. 1). The curved beam consists of two straight legs connected by a 90o bend with a 6.4-mm inner radius. An out-of-plane (through-the-thickness) tensile stress is produced in the curved region of the specimen when load is applied. This test method is limited to use with composites consisting of layers of fabric or layers of unidirectional fibers.
1.2 This test method may also be used to measure the interlaminar tensile strength if a unidirectional specimen is used where the fibers run continuously along the legs and around the bend.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.4 The values stated in SI units are to be regarded standard. The values given in parentheses are provided for information purposes only.

SCOPE
1.1 This test method determines the number of cycles (N) for the onset of delamination growth based on the opening mode I cyclic strain energy release rate (G), using the Double Cantilever Beam specimen shown in Fig 1. This test method applies to constant amplitude, tension-tension fatigue loading of continuous fiber-reinforced composite materials. When this test method is applied to multiple specimens at various G-levels, the results may be shown as a G-N curve, as illustrated in Fig. 2.
1.2 This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with single-phase polymer matrices. This limited scope reflects the experience gained in round robin testing. This test method may prove useful for other types and classes of composite materials, however, certain interferences have been noted (see Section 6.5 of Test Method D 5528).
1.3 The values stated in SI units are to be regarded as standard. The values provided in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.