层裂试验的数值模拟

近年来,层裂试验被用于测量脆性材料的动态拉伸强度,学者们提出通过初始层裂位置以及自由表面速度来计算层裂强度的方法,这两种方法的计算精度需要进一步研究.本文通过有限元模拟研究了层裂试验,结果表明,采用层裂位置来计算层裂强度的方法可以获得较高的精度,但是对波形有一定的要求.不应该采用半正弦波,而应该采用上升沿和下降沿部队称的波形.采用自由表面速度来计算层裂强度的方法应该采用上升沿时长小于下降沿的波形,但是无论采用什么样的波形,此方法基于简单波理论,带来不可忽略的误差,还需要进一步的改进和研究.

Numerical Simulation of Spalling Test

Spalling test has been adopted recently for the dynamic tensile testing of brittle materials . Scholars have put forward the methods of measuring spall strength with initial spall location or the free surface ve -locity.The accuracy of these two methods needs to be studied .This paper mainly investigated spalling test using finite element simulation .The result shows that the method of calculating spall strength with initial spall location can achieve adequate accuracy but should be carefully taken to the influence of the waveform in which asymmet -ric waveform （ time of the rising and falling edge of the pulse are different ） should be adopted .The spall strength can also be measured from the free surface velocity of the specimen .The waveform , of which the rising time is less than the falling time , should be adopted .However , the free surface velocity measurement method is based on the simple wave theory which can bring non -negligible error , further research should be carried on .