Experimental Researches Concerning the Properties of Composite Materials with Random Distribution of Reinforcement

In this paper we present the result of the experiments performed to obtain the characteristics curves for five composite materials with random distribution of reinforcement. From these curves we determined the elasticity modulus and the resistance to fracture. Using the modal identification method we determined the first eight eigenmodes for two bars from composite materials (Bar I phenolic fireproof resin reinforced with fiberglass; Bar 2 - ortophtalic polyesteric resin reinforced with fiberglass), embedded at one end and free at the other We determined the eigenpulsations for the modes considered and we used the first four modes for the calculus of elasticity modulus. The results obtained by traction testing compared with the one from Modal identification method certify the utilization of modal analysis in the determination of properties of composite structures.