1.1 These test methods cover the determnation of flexural
properties of unreinforced and reinforced plastics, including
high-modulus composites and electrical insulating materials in
the form of rectangular bars molded directly or cut from sheets,
plates, or molded shapes. These test methods are generally
applicable to both rigid and semigid materials. However
flexural strength cannot be determined for those materials that
do not break or that do not fail in the outer surface of the test
specimen within the 5.0 % strain limit of these test methods.
These test methods utilize a thee-point loading system applied
to a simply supported beam. A four-point loading system
method can be found in Test Method D 6272.