ASTM D6415/D6415M-06 - 1.1.2006
 
1. 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.

 
2. Referenced Documents

E6-25

Standard Terminology Relating to Methods of Mechanical Testing

D792-20

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

D883-26a

Standard Terminology Relating to Plastics (Includes all amendments and changes 6/15/2026).

D3171-22

Standard Test Methods for Constituent Content of Composite Materials

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

E122-17(2022)

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

E4-24

Standard Practices for Force Calibration and Verification of Testing Machines

E177-26a

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

E456-13a(2022)e1

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

E1309-00

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

E1434-00

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

E1471-92(1998)

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

D5687/D5687M-20

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