Shock Wave Propagation Characteristics and Material Hydrodynamic Response under Non-Uniform Converging Loading

The application of converging shock waves to compress solid materials can generate high-temperature and high-pressure environments, achieving a high compression ratio and high-density state, which is of significant importance for industrial applications. However, due to loading methods and material defects, converging shock waves often exhibit spatiotemporal non-uniform characteristics, leading to complex wave structures that reduce the compression performance of the converging shock waves. Therefore, it is crucial to study the propagation and evolution characteristics of non-uniform converging shock waves in solid media for achieving high-density and high-compression states in materials. Based on magnetically driven loading device, this study uses uniform cylindrical flyers to impact preabricated cylindrical targets with different amplitudes, generating non-uniform converging shock waves propagating inward. By employing 24-channel integrated laser velocimeter probes arranged in an offset pattern, the free-surface jump time and velocity are measured. Combined with numerical simulations, the study investigates the propagation characteristics of non-uniform converging shock waves and reveals the dynamic response characteristics of the interaction between non-uniform converging shock waves and materials. The research findings indicate that the intersection region of non-uniform converging shock waves exhibits an intersection enhancement effect, leading to a reverse growth characteristic of the free-surface spike amplitude. Unlike converging shock waves in gas, under the action of non-uniform converging shock waves and their derivative wave systems (free-surface reflection waves), the free surface exhibits spallation. Additionally, under the combined effects of convergence and shock wave intersection, the spallation and ejection of the working layer are more dispersed, the velocity of ejection are higher. Furthermore, shock wave intersections cause the free surface to accelerate, resulting in high-velocity points. Under the action of the derivative wave system of non-uniform converging shock waves, the free surface also exhibits secondary loading phenomena. These findings provide a certain foundation for the dynamic propagation study of non-uniform converging shock waves and hold theoretical significance for the development of compression science.