带裂纹三点弯曲试样的动态应力强度因子分析

提出了计算带单边裂纹三点弯曲试样动态应力强度因子的新方法．首先由权函数的普遍形式和两种参考载荷下的应力强度因子，得到了带单边裂纹三点弯曲试样的权函数，然后考虑试样的转动惯性和剪切变形，根据振动理论推导出无裂纹梁内的动应力响应和分布，最后由权函数的思想推导出了带裂纹三点弯曲试样动态应力强度因子公式．通过有限元数值计算，验证了该方法的正确性，结果比较表明公式具有较高的精度．另外，还研究了冲击载荷下三点弯曲试样的动态应力强度因子随裂纹长度和加载速率的变化规律．

Analysis of Dynamic Stress Intensity Factors of Three-Point Bend Specimen Containing Crack

A new formula was produced to calculate dynamic stress intensity factors of three-point bend specimen containing a single edge crack. Firstly,the weight function for three-point bend specimen containing a single edge crack was derived from a general weight function form and two reference stress intensity factors. The coefficients of the weight function were given. Secondly,the history and distribution of dynamic stresses in unflawed three-point bend specimen which takes account of the effects of rotator inertia and shear deformation were inferred according to vibration theory. Finally,the dynamic stress intensity factor equations for three-point bend specimen with a single edge crack subjected to impact loadings were obtained by weight function method. The new formula was verified by the comparison with the numerical results of FEM(finite element method). Good agreement was achieved. And the law of dynamic stress intensity factors of three-point bend specimen under impact loadings changing with crack depths and loading rates was studied.