Standard Test Methods for Structural Panels in Flexure

Theory:

ASTM D3043 covers several procedures for testing the flexural properties of structural panels. These panels can be of different materials used to form plane structures such as floors, walls and ceilings. These materials can include plywood, particle board, strand board, veneer composites, and other wood type materials. 

 

There are several test methods including Test Method A which is a 3 point bend test with Center-Point Flexure. Method B is a 4 point test with Two-Point Flexure in the middle of the board. Method C is a Pure Moment Test also known as a two point bend test. Finally, Method D specifies a flexure test for QA/QC where the test board is not tested to failure. 

Geometry:

Test specimens are strips cut from panels that are up to 4' by 8'. The strips can be of varying sizes, however it is important that technicians record and use the same size specimen when comparing results. 

Solution:

A 3 or 4 point bend testing jig may be used to perform the respective test. There are many sizes available and they are usually specified by the customer. 

Analysis:

The modulus of elasticity is also referred to as the flexural modulus. This calculation is a function of the flexural strength and is tabulated according to ASTM D3043. Several factors including moisture content and specific gravity can affect the calculations. Modulus of Rupture can also be determined however it is subject to a notable degree of error based on the bottom span, loading points, and the total deflection at failure. 

ASTM D3043

Structural Panel Flex Test