ASME应变强化本构模型及压力容器安全裕度分析

Analysis of the ASME Constitutive Mode with Strain Effect and Safety Margin for Pressure Vessels

弹塑性有限元分析需要材料的真实应力—应变曲线,但利用ASME中的应变强化本构模型,按标准保证值和实测值分别建立的ASME真实应力—应变曲线存在较大的差异。运用ANSYS有限元软件模拟同一个1.4301奥氏体不锈钢压力容器模型在这两种材料参数下筒体应力、应变以及爆破压力的差异,并将模拟结果与试验结果对比。同时利用有限元模拟和爆破试验的爆破压力结果,分析奥氏体不锈钢应变强化压力容器在不同预应变下的安全裕度和实际安全裕度。结果表明:按保证值材料参数设计的压力容器,容器的实际塑性应变要比理论值小很多,用实测值材料参数设计大变形压力容器时应严格控制实际的应变值;应变强化压力容器的理论设计应变可达10%,但实际应变应在5%左右,容器才具有足够的安全裕度。

The elastic-plastic analysis method need true strain-stress relationship.The true stress-strain curves can be established with the ASME constitutive mode.But there are big differences between the two true ASME stress-strain curves established independently by standard material values and measured material values.Obtain stress,strain and burst pressure differences on the 1.4301 austenitic stainless steel cylinder from the results of finite element analysis with the two material parameters,and then compare the simulation results with the bursting test data.Analyze the pre-strain safety margins of strain hardening pressure vessels of austenitic stainless steel by the simulation results and bursting test data.The results show that the actual plastic strain is much smaller than the theoretical value for the pressure vessels designed with standard material values and it is unreasonable to design the large-deformation pressure vessels with measured material values.For the strain hardening pressure vessels,its theoretical plastic can be up to 10%,but its actual plastic should be about 5% in order to ensure the pressure vessels have sufficient safety margin.