The formulas of the load and displacement of bellow are expanded in Fourier series along circumferential angel. The computation time can be decreased.

• 将波纹管离散为锥壳单元，单元之间用节点圆相连结，载荷和位移沿环向展开成傅立叶级数，这样降低了计算维数，减少了计算工作量。