Through multiple generation calculation, the minimum point of penalty function value was obtained, then the optimalc reduction distribution was found. 通过粒子群多代运算，求出罚函数值最小点，得到压下负荷最佳分配点。
The modified penalty method is used to treat incompressible constraints, so that volumetric locking is avoided. 采用修正的罚函数法约束体积不变条件，避免体积闭锁现象的产生。
