液压膨胀环动态拉伸碎裂的有限元模拟

FEM Simulation of Dynamic Fragmentation of Liquid-driving Expanding Ring

液压冲击膨胀环实验平台能有效地实现韧性金属圆环在高应变率拉伸载荷作用下的动态断(碎)裂.论文采用流固耦合的有限元数值计算方法,模拟了实验过程中金属圆环在高压液体作用下的运动、变形和断裂现象.分析了装置和试件的接触应力对试件碎裂过程的影响并讨论了如何实现液压对试件的有效加载.计算结果表明,实验中的初始接触应力和液体的较长时间加载对试件的碎裂过程没有显著影响;在合理的加载条件下,液压膨胀环实验技术是研究固体动态拉伸碎裂的有效手段.

The experimental platform of liquid-driving expanding ring has been an effective technique for investigating the dynamic fragmentation of ductile metal ring under high-strain-rate tensile loading.In this work,the finite element method for fluid-structure interaction is used to simulate the expansion and fracture process of ductile metal ring under the action of high-pressure liquid observed in the experiment.First,the problem of how to simulate the effective hydraulic pressure loading on the specimen is discussed,and the simulation results are compared with those subjected to an initial velocity.Second,the influence of the contact stress between the device and the specimen on the fragmentation process is analyzed.Based on the simulation results,the movement,deformation and fracture of metal rings are clearly observed,and the entire process is analyzed in detail.It is found that the duration of loading process does not significantly affect the size of debris produced during the tensile fragmentation under high strain rates.And to some extent,the initial contact pressure and the friction force between the specimen and the device have little influence on the expansion process of the specimen and the size of debris.Verified by both numerical simulation and experimental results,it is shown that under proper loading conditions,the one-dimensional stress condition and free expansion of specimens can be satisfied with the liquid-driving expanding ring,which is an effective and reliable experimental method to study the problem of solid fragmentation.