The in-plane tensile properties of polymer matrix composite materials reinforced by high-modulus fibers may be determined using the test procedures detailed in ASTM D3039. These test methods cover a wide range of specimen dimensions as well as many different testing configurations as well as provisions for testing at high and low tempera The composite material forms are limited to continuous fiber or discontinuous fiber-reinforced composites in which the laminate is balanced and symmetric with respect to the test direction. Properties, in the test direction, which may be obtained from this test method, include the following: ultimate tensile strength, ultimate tensile strain, tensile chord modulus of elasticity, Poisson's ratio, and transition strain.