ASTM D790 – Flexural Properties of Plastics and Electrical Insulating Materials

Standard: ASTM D790 Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials

Scope: Per ASTM D790: "These test methods are used to determine the flexural properties of unreinforced and reinforced plastics, including high modulus composites and electrical insulating materials utilizing a three-point loading system to apply a load to a simply supported beam (specimen). The method is generally applicable to both rigid and semi-rigid materials, but flexural strength cannot be determined for those materials that do not break or yield in the outer surface of the test specimen within the 5.0 % strain limit."

Products: Plastics (but many specifications have also adapted this standard for use with many product and material types)

Procedure: Per ASTM D790: "A test specimen of rectangular cross section rests on two supports in a flat-wise position and is loaded by means of a loading nose located midway between the supports. [Typically], a support span-to-depth (of specimen) ratio 16:1 shall be used. The specimen is deflected until rupture occurs in the outer surface of the test specimen or until a maximum strain…of 5.0 % is reached, whichever occurs first."

Result: Test results such as flexural stress/strain may be reported.