论文部分内容阅读
我们用旋转和速度这样两个场矢量代替了传统的位移矢量,来描述弹性介质的状态变化.利用新的场变量可以获得一组弹性介质的动力学关系或场方程.现在作为场源的是用平均应力定义的应力变化率和应力集中,显然这对于讨论介质中存在裂纹和裂纹扩展这样一类动力学问题无疑是方便的.由场的能量动量张量和动量守恒定律,我们得到了旋转和应力集中相互作用的重要概念.最后我们讨论了型Ⅰ和Ⅱ型裂纹端部这种相互作用的图象,计算了相互作用的大小和方向.
We replace the traditional displacement vector with the two field vectors, such as rotation and velocity, to describe the state change of elastic media, and use a new field variable to get a set of dynamic relationships or field equations for elastic media. Now as a field source, The rate of stress change and the stress concentration, defined by mean stress, are obviously convenient for discussing the dynamical problems of existence of cracks and crack propagation in the medium. From the field of momentum momentum tensor and momentum conservation law, we obtain the rotation And stress concentration interaction.Finally, we discuss the interaction between type I and type II crack ends and calculate the size and direction of the interaction.