This test method covers the determination 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 rigid and semirigid materials. However, flexural
strength cannot be determined for those materials that do not
break or that do not fail in the outer fibers. This test method
utilizes a four point loading system applied to a simply
supported beam