Abstract
In this paper, we obtained experimentally the elasticity modulus and tensile strength, for four types of composite materials made of epoxy resin reinforced with wheat straw, with different spatial orientation for reinforced. Using experimental results, we have obtained the original formulas, for the calculus of tensile strength and elasticity modulus, for the types of specified materials. These relationships are dependent on the percentage of fibers oriented in the direction of request, and which have the length equal with the test sample. In the case in which the percentage is equal to unit, the relations coincide with the ones from unidirectional composite materials. We determined experimentally the coefficient of internal damping and eigen frequencies, for bars embedded at one end and free at the other, made from epoxy resin reinforced with wheat straw, targeted unidirectional, bidirectional and random. Keywords: composite materials, elasticity modulus, tensile strength, damping coefficient, wheat straw