ASTM D7291/D7291M-22 - 15.10.2022
 
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.

 
1. 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?UnitsThe 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.

 
2. Referenced Documents

D883-26

Standard Terminology Relating to Plastics

E1434-00

Standard Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in Databases

D3878-26

Standard Terminology for Composite Materials

D5229/D5229M-20

Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials

D5687/D5687M-20

Standard Guide for Preparation of Flat Composite Panels with Processing Guidelines for Specimen Preparation

D6415-99e1

Standard Test Method for Measuring the Curved Beam Stength of a Fiber-Reinforced Polymer-Matrix Composite

E4-24

Standard Practices for Force Calibration and Verification of Testing Machines

E6-25

Standard Terminology Relating to Methods of Mechanical Testing

E122-17(2022)

Standard Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process

E177-26a

Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods (Includes all amendments and changes 5/14/2026).

E251-20a

Standard Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages (Includes all amendments and changes 8/7/2020).

D792-20

Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement

E1471-92(1998)

Standard Guide for Identification of Fibers, Fillers, and Core Materials in Computerized Material Property Databases

E1309-00

Standard Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in Databases

E691-23

Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

E456-13a(2022)e1

Standard Terminology Relating to Quality and Statistics (Includes all amendments and changes 4/16/2024).

E1012-19

Standard Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application

D3171-22

Standard Test Methods for Constituent Content of Composite Materials