外表面体积型缺陷对高压管件剩余强度的影响

应用ANSYS软件研究了高压管件在105 MPa内压作用下外表面体积型缺陷的类型、缺陷深度、轴向长度和缺陷宽度等形状参数对高压管件Mises应力的影响规律。研究结果表明,对于矩形缺陷,轴向长度对管件强度的影响较大,轴向长度与最大应力呈二次函数关系;Mises应力随着缺陷宽度的增加逐渐减小,当宽度达到一定值后应力趋于一稳定值,在缺陷深度小于2 mm时,缺陷宽度对缺陷处应力的影响很小,深度大于2 mm时,缺陷宽度对缺陷处应力的影响逐渐增大。缺陷深度是影响管件剩余强度的最重要因素,随着深度的增加,缺陷处Mises应力均明显增加;孔径对缺陷处最大应力的影响规律与孔的深度有关。通过计算给出了缺陷尺寸参数的临界值,为高压管件安全评价提供了参考依据。

Effects of External Surface Volumetric Defect on the Residual Strength of High Pressure Pipe

The ANSYS software was applied to analyze the high pressure fittings with external surface volumetric defects under the effect of internal pressure.The law of effects of the shape parameters,such as type,defect depth,axial length and defect width of external surface volumetric defects,on the Mises stress of high pressure pipe under the effect of 105 MPa internal pressure,was studied.The research findings show that as for rectangular defect,axial length has considerable effect on pipe strength.The axial length and maximum stress are of quadratic function relationship.The Mises stress gradually decreases with the increase of defect width.When the width reaches a certain value,the stress tends to be a stable value.When the defect depth is less than 2 mm,the defect width has relatively slight effect on the stress at the position of defect.It can be negligible.When the depth is greater than 2 mm,the defect width has gradually increasing effect on the defect stress.The effects of defect width on defect stress should be considered.The defect depth is the most important factor influencing the residual strength of fittings.Whether it is rectangular defect or hole defect,the Mises stress at the defect position increases remarkably with the increase of the depth.The law of effects of hole diameter on the maximum stress at the defect position is related to hole depth.The critical value of defect size parameters was given through calculation.The study can serve as a reference for the safety evaluation of high pressure pipe fittings.