ASTM C297/C297M-04(2010) - 1.10.2010
 
Significance and Use

In a sandwich panel, core-to-facing bond integrity is necessary to maintain facing stability and permit load transfer between the facings and core. This test method can be used to provide information on the strength and quality of core-to-facing bonds. It can also be used to produce flatwise tensile strength data for the core material. While it is primarily used as a quality control test for bonded sandwich panels, it can also be used to produce flatwise tensile strength data for structural design properties, material specifications, and research and development applications.

Factors that influence the flatwise tensile strength and shall therefore be reported include the following: facing material, core material, adhesive material, methods of material fabrication, facing stacking sequence and overall thickness, core geometry (cell size), core density, adhesive thickness, specimen geometry, specimen preparation, specimen conditioning, environment of testing, specimen alignment, loading procedure, speed of testing, facing void content, adhesive void content, and facing volume percent reinforcement. Properties that may be derived from this test method include flatwise tensile strength.

 
1. Scope

1.1 This test method determines the flatwise tensile strength of the core, the core-to-facing bond, or the facing of an assembled sandwich panel. Permissible core material forms include those with continuous bonding surfaces (such as balsa wood and foams) as well as those with discontinuous bonding surfaces (such as honeycomb).

1.2 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.

1.3 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.

 
2. Referenced Documents

D792-20

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

D883-26b

Standard Terminology Relating to Plastics (Includes all amendments and changes 8/24/2026).

D3171-22

Standard Test Methods for Constituent Content of Composite Materials

D3878-26

Standard Terminology for Composite Materials

E4-24

Standard Practices for Force Calibration and Verification of Testing Machines

E6-25

Standard Terminology Relating to Methods of Mechanical Testing

D2734-23

Standard Test Methods for Void Content of Reinforced Plastics

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).

C271/C271M-16(2022)e1

Standard Test Method for Density of Sandwich Core Materials (Includes all amendments and changes 5/11/2022).

D3039/D3039M-17(2025)

Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials

D5229/D5229M-20

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

D2584-25

Standard Test Method for Ignition Loss of Cured Reinforced Resins

E122-17(2022)

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