氧化铝陶瓷动态压缩强度的高压和高应变率效应

Effects of high pressure and high strain rate on dynamic compressive strength of alumina

平面冲击压缩下材料由弹性到非弹性变形转变的临界值对应着材料的动态压缩强度,高压和高应变率强烈影响材料的强度。采用粘塑性比拟法建立了材料发生非弹性变形的动态屈服条件,并引入Drucker-Prager静态屈服准则,可以联合考虑动态压缩强度的高压和高应变率效应,据此提出了新的Hugoniot弹性极限表征形式。利用轻气炮进行了氧化铝陶瓷平板冲击实验,VISAR测试了样品的自由面速度历程,讨论了氧化铝陶瓷动态压缩强度的测定和存在的不确定性问题。

Critical value which transforms from elastic deformation to inelastic deformation is corresponding with the compression strength of the material under the plane impact compression.Hydrostatic pressure and high strain-rate influenced material strength seriously.In this paper,we establish a non-elastic deformation of the dynamic yield condition based on the viscoplastic material law analogy,and introduce the Drucker-Prager static yield criterion to consider the effect of hydrostatic pressure and high strain-rate.We give a new representation of Hugoniot elastic limit.The shock compression experiments of alumina ceramics were carried out under 1D strain state one-stage gas gun and free surface velocity histories of particles in alumina were measured by VISAR.The experimental determination of the dynamic strength of alumina was discussed and open problems were clarified.