ASTM D790

Because the flexural properties of plastics are critical in so many applications, ASTM D790 is one of the most commonly utilized test methods in the plastics industry. It measures the flexural strength and flexural modulus of both reinforced and unreinforced plastics, which also includes high-modulus composites and electrical insulating materials. Determining these mechanical characteristics will allow the proper selection and quality control of plastic materials that undergo bending forces when in operation. As usual, because these materials are sensitive to changes in temperature, testing at application temperature may be necessary.

 

In this procedure, a three- or four-point loading scheme is applied to a rectangular bar test specimen using a universal test machine and a three- or four-point bend fixture. The strain rate applied depends on the relative amount of specimen deflection, with a faster rate being applied to higher bending materials. The test continues until either the specimen breaks or it reaches 5% deflection. ASTM D790 is very similar to ISO 178, except that the ISO standard test continues until the specimen breaks.

 

Solutions for ASTM D790 typically include these types of components:

 

 

Both the premium MTS Criterion® and the economical MTS Exceed® universal testing machines are ideal for flexural testing of unreinforced and reinforced plastics and electrical insulating materials per ASTM D790. These test systems come in a variety of force capacities and frame styles, ranging from 1-column tabletops to larger 2-column floor-standing models. The 30kN and 100kN models also have dual zone test spaces to reduce set-up times if you frequently change test requirements. And as an alternative to a new load frame, you can modernize the software and controls of your old test system with an MTS ReNew™ Upgrade.

 

 

For other options related to this standard, please download the application test method tech note on this page.