in general, there are two kinds of calculation method of corrugated pipe stress: EJMA stress calculation method for the numerical method and the United States. Metal corrugated pipe as an elastic sealing parts, the first to meet strength conditions, namely the maximum stress is less than allowable stress under the given conditions. Allowable stress can be obtained from limit stress divided by the safety factor. According to the working conditions of the corrugated pipe and its application requirements, can be the yield strength, ultimate stress can also be a bellows instability when the critical stress or fatigue strength. To compute bellows biggest

working stress must stress distribution analysis of corrugated pipe wall. Assume that whole corrugated corrugated pipe in the same condition, the study only in counting bellows corrugated single half wave. So, in the study do not consider the end corrugated, though the end corrugated boundary

a and middle corrugated is different. Lestat, rotary shell with variable wall thickness listed in axial symmetry deformation to solution of the nonlinear equations. Lestat, equation, generally assume that the application of thin shell theory, including: compared with the curvature radius of the main ring and shell thickness is small assumption; The material of the assumption of homogeneity and isotropy. Using the above assumptions will bring certain error calculation. Because in manufacturing corrugated pipe, pipe rolling, deep drawing and subsequent corrugated plastic forming causes material anisotropy on the mechanical properties and

inhomogeneity.