Direct calculation of sound speed of materials under ramp wave compression

Accurate loading-unloading sound speed of materials is indispensable for material equation of states and strength calculation at high pressure. In this paper, we propose an approach to calculate the loading-unloading sound speed of materials under ramp wave compression directly based on the characteristic theory. The feasibility of this method is validated numerically, and it is applied to the loading-unloading sound speed calculation of copper and tantalum under ramp wave compression. Calculated sound speeds agree well with the results of other methods reported in literatures, and the comparison show that this method is concise and efficient.