Escauriza E M, Duarte J P, Chapman D J, Rutherford M E, Farbaniec L, Jonsson J C, Smith L C, Olbinado M P, Skidmore J, Foster P, Ringrose T, Rack A, Eakins D E
Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK.
ESRF - The European Synchrotron, CS40220, F-38043, Grenoble, France.
Sci Rep. 2020 May 21;10(1):8455. doi: 10.1038/s41598-020-64669-y.
Extraordinary states of highly localised pressure and temperature can be generated upon the collapse of impulsively driven cavities. Direct observation of this phenomenon in solids has proved challenging, but recent advances in high-speed synchrotron radiography now permit the study of highly transient, subsurface events in real time. We present a study on the shock-induced collapse of spherical cavities in a solid polymethyl methacrylate medium, driven to shock states between 0.49 and 16.60 GPa. Utilising multi-MHz phase contrast radiography, extended sequences of the collapse process have been captured, revealing new details of interface motion, material failure and jet instability formation. Results reveal a rich array of collapse characteristics dominated by strength effects at low shock pressures and leading to a hydrodynamic response at the highest loading conditions.
在脉冲驱动的空穴坍塌时，可产生高度局部化的压力和温度的异常状态。在固体中直接观察这一现象已被证明具有挑战性，但高速同步辐射成像技术的最新进展现在允许实时研究高度瞬态的地下事件。我们展示了一项关于在固体聚甲基丙烯酸甲酯介质中，由冲击驱动的球形空穴坍塌的研究，该介质被驱动至0.49至16.60吉帕的冲击状态。利用多兆赫相衬成像技术，捕捉到了坍塌过程的扩展序列，揭示了界面运动、材料破坏和射流不稳定性形成的新细节。结果显示，在低冲击压力下，坍塌特征以强度效应为主，在最高加载条件下则导致流体动力学响应，呈现出丰富多样的坍塌特性。
