基于动态光弹性方法的冲击载荷作用下自由边界主应力研究

Research on Principal Stress on Free Boundary Subjected to Impact Loading Based on Dynamic Photoelastic Method

当物体在冲击载荷作用下,物体内部会产生应力波,研究应力波的传播过程及规律对研究物体受冲击载荷作用具有重大的意义。应力波在物体内传播时,在自由边界处产生的主应力状态对于理论求解和计算有着重要意义。采用动态光弹性方法,结合新型动光弹系统及相关实验设备采集物体在冲击载荷作用下的等倾线和等差线条纹图,通过分析等倾线的条纹,得出等倾线与自由边界相交所成角度不为0°或90°,得出在物体自由边界处两个主应力均存在且不为零的结论。针对上述结果,采用电测方法进行验证,两试验结果相符合,方案可行且准确。

When an object was subjected an impact loading, stress wave was produced in the object. Stud- ying the regularity of stress-wave propagation was significant to the study of objects subjected to impact loading. When stress wave travelled in the object, principal stress on free boundary was useful to theoretical analysis and calculation. A new kind of dynamic photoelastic apparatus was used. Isochromatic and isoclinic of the object subjected to impact loading could be obtained combining dynamic photoelastic ex- periment and related test equipment. By analyzing the isoclinic, a conclusion was obtained that the angle between the isoclinic and the free boundary was not 0 or 90 . So the two principal stresses on the bounda- ry exist and they were not 0. Electrometric method was used to prove the above-mentioned conclusion. Analysis showed the result of dynamic photoelastic method was compatible with the result of electrometric method. So the method in this article was feasible and accurate.