摘要
为了得到陶瓷材料有效的实验结果,必须采用多种改进措施(PulseShaper、高强度和高刚度垫块、直接测试试样应变以及使用较大长径比的试样)来满足SHPB装置所要求的基本假设条件。研究以A95陶瓷的测试为例,通过数值模拟分析证明:针对陶瓷材料改进的SHPB装置,可以得到陶瓷材料的有效压缩应力 应变曲线和压缩破坏强度。但是在分析材料的压缩破坏强度时,必须排除劈开破坏的干扰。数值模拟研究发现,压缩测试中出现的劈开破坏是由卸载过程中出现的局部横向(沿直径)拉伸造成的拉伸破坏。在修正了弥散对压缩破坏强度的影响后,研究得到了A95陶瓷的压缩破坏强度为3.5GPa。A95陶瓷的高应变率压缩应力 应变曲线显示了良好的线弹性,并且曲线的斜率与杨氏模量相同。
The characteristics of ceramics - high strength, high Young's Modulus and brittleness challenge the validity of basic assumptions for the SHPB experiments. Some modifications on the test configuration have been done such as pulse shaper, high strength pads, direct measurement of the specimen strain and so on. This research shows that a valid compression stress-strain curve and compression strength of A95 ceramic can be obtained with the modified SHPB technique, which is verified by the numerical simulation of the test. A95 ceramic shows a good linear elastic stress-strain curve. The split failure of A95 ceramic would be caused by the localized tension during unloading according to the numerical simulation. Therefore, the compression strength measurements are not valid for the split specimens. After related correction of dispersion in the failure strength data under compression, the failure strength of A95 ceramic is determined as 3.5 GPa.
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
2004年第3期233-239,共7页
Explosion and Shock Waves
关键词
固体力学
压缩
SHPB
陶瓷
应力一应变曲线
破坏强度
Compressive strength
Computer simulation
Dynamics
Failure (mechanical)
Strain rate
Unloading
