ASTM D790 Flexural Test – Specimen Size

Flexural properties testing by ASTM D790, a commonly used test in the plastics industry, measures the flexural modulus and flexural strength of reinforced and unreinforced plastic materials. The results obtained indicate the stiffness of the test material, enabling the choice of materials that do not bend when supporting the loads needed for a required application.

ASTM D790 Flexural Test – Specimen Size

• Test specimens of the rectangular cross-section are injection molded, cut from molded or extruded sheets or plates, or cut from molded or extruded shapes. Specimens must be solid and uniformly rectangular. The specimen rests on two supports and is loaded utilizing a loading nose midway between the supports.
• A wide variety of shapes are allowed in this test; however, the general specimen size for ASTM D790 is 3.2 mm × 12.7 mm × 125 mm (approx. 0.125-inch × 0.5 inch × 5.0 inch), and for ISO 178 is 10 mm × 4 mm × 80 mm.

Common Uses

As determined by this ASTM D790 test method, flexural properties are especially useful for quality control and specification purposes. They include:

• Flexural stress
• Flexural stress for beams tested at large support spans
• Flexural strength
• Flexural offset yield strength
• Flexural stress at break
• Stress at a given strain
• Flexural strain
• Modulus of elasticity

Industrial Applications

• Determination of flexure strength and flexural modulus help product designers in choosing the most appropriate plastic or composites for their application.
• Products designed with low flexural strength materials, like sporting equipment, may not survive long-term use. This is why the ASTM D790 test is carried out in manufacturing industries that manufacture sports equipment, automotive parts, and construction materials.