存在内表面轴向裂纹压力容器的模态分析

Modal Analysis of Pressure Vessel with Inner Surface Axial Crack

压力容器在制造和焊接过程中及服役期间都无法避免裂纹的产生。裂纹会使压力容器的强度和刚度明显降低,还会在高温、高压、强腐蚀等极端服役环境下扩展,使压力容器结构断裂的概率增大,容易导致安全事故的发生。采用有限元软件ANSYS Workbench建立有无内表面轴向裂纹的压力容器圆筒模型,计算出不同裂纹深度和位置条件下压力容器的自振频率,分析裂纹深度和位置对压力容器安全性的影响规律。研究结果表明,压力容器的自振频率随着裂纹相对深度的增加而减小,裂纹所处的位置越靠近筒体中间时越危险。

It is inevitable to occurrence of cracks when pressure vessel during the fabrication,welding and service.Cracks not only significantly reduce the strength and rigidity of the pressure vessel,but also expand in extreme service environments such as high temperature,high pressure,and strong corrosion.The increased probability of fracture of the pressure vessel structure can easily lead to safety accidents.The cylinder model was established by using the finite element software ANSYS Workbench,the natural frequency of the pressure vessel under different crack depths and positions was calculated,the influence of crack depth and position on the safety of the pressure vessel was analyzed.The research results show that the natural frequency of the pressure vessel decreases with the increase of the relative depth of the crack,and the most dangerous position located closer to the middle of the crack barrel.