中文说明：利用ansys计算的应力结果，求出截面内力，再利用材料力学公式求等效应力（此例是求坝基面的等效应力）
English Description：
According to the stress results calculated by ANSYS, the internal force of the section is calculated, and then the equivalent stress is calculated by using the material mechanics formula (this example is to calculate the equivalent stress of the dam foundation surface)