STRESS WAVE VELOCITY PROPAGATING IN COMPOSITES AND ITS APPLICATION TO SOUNDNESS EVALUATION OF STRUCTURES

Stress wave velocities propagating in the laminated composites and the cylindrical composites, which are reinforced by the fibers oriented in the cylindrical array. over the cross section, are investigated using the dynamic laminated element method and finite prism method. The dispersion characteristics, which is caused by the orientation of the fibers as well as the shape of the cross section, of the wave velocity as a function of wave number are numerically obtained. Several cases involving various ratios of elastic constants of the fiber and the matrix were investigated. In order to apply above results the stress wave velocities propagating in the damaged cylinder model, just like the cylinder with surface cracks and the cylinder deteriorated from the surface , are obtained numerically