ASTM C365/C365M-16
Standard Test Method for Flatwise Compressive Properties of Sandwich Cores

Standard No.

ASTM C365/C365M-16

Release Date

2016

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM C365/C365M-22

Latest

ASTM C365/C365M-22

Scope

5.1 Flatwise compressive strength and modulus are fundamental mechanical properties of sandwich cores that are used in designing sandwich panels. Deformation data can be obtained, and from a complete force versus deformation curve, it is possible to compute the compressive stress at any applied force (such as compressive stress at proportional limit force or compressive strength at the maximum force) and to compute the effective modulus of the core.

5.2 This test method provides a standard method of obtaining the flatwise compressive strength and modulus for sandwich core structural design properties, material specifications, research and development applications, and quality assurance.

5.3 In order to prevent local crushing of some honeycomb cores, it is often desirable to stabilize the facing plane surfaces with a suitable material, such as a thin layer of resin or thin facings. Flatwise compressive strength data may be generated using either stabilized specimens (reported as stabilized compression strength) or non-stabilized specimens (reported as bare compression strength). It is customary aerospace industry practice to determine compression modulus only when using stabilized specimens.

5.4 Factors that influence the flatwise compressive strength and shall therefore be reported include the following: core material, methods of material fabrication, core geometry (cell size), core density, specimen geometry, specimen preparation, specimen conditioning, environment of testing, specimen alignment, loading procedure, and speed of testing.

1.1 This test method covers the determination of compressive strength and modulus of sandwich cores. These properties are usually determined for design purposes in a direction normal to the plane of facings as the core would be placed in a structural sandwich construction. The test procedures pertain to compression in this direction in particular, but also can be applied with possible minor variations to determining compressive properties in other directions. 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 This test method does not cover the determination of compressive core crush properties. Reference Test Method D7336/D7336M for determination of static energy absorption properties of honeycomb sandwich core materials.

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 determ......

ASTM C365/C365M-16 Referenced Document

• ASTM C271/C271M Standard Test Method for Density of Sandwich Core Materials
• ASTM D3878 Standard Terminology Composite Materials
• ASTM D5229/D5229M Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• ASTM D7336/D7336M Standard Test Method for Static Energy Absorption Properties of Honeycomb Sandwich Core Materials
• ASTM D883 Standard Terminology Relating to Plastics
• ASTM E122 Standard Practice for Calculating Sample Size to Estimate, With a Specified Tolerable Error, the Average for Characteristic of a Lot or Process
• ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E4 Standard Practices for Force Verification of Testing Machines
• ASTM E456 Standard Terminology for Relating to Quality and Statistics
• ASTM E6 Standard Terminology Relating to Methods of Mechanical Testing

ASTM C365/C365M-16 history

• 2022 ASTM C365/C365M-22 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores
• 2016 ASTM C365/C365M-16 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores
• 2011 ASTM C365/C365M-11a Standard Test Method for Flatwise Compressive Properties of Sandwich Cores
• 2011 ASTM C365/C365M-11 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores
• 2005 ASTM C365/C365M-05 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores
• 2003 ASTM C365-03 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores
• 2000 ASTM C365-00 Standard Test Method for Flatwise Compressive Properties of Sandwich Cores