深拉成形液氮生物容器残余应力数值模拟研究

NUMERICAL SIMULATION OF RESIDUAL STRESS IN DEEP DRAWN LIQUID NITROGEN BIOLOGICAL CONTAINERS

深拉成形具有制造工艺简单、制造效率高等优点,在压力容器制造中得到了广泛应用,但是经过该方法成形的不锈钢圆筒件容易产生残余应力,影响液氮生物容器质量。文中为了研究压边力、摩擦系数、凹模圆角半径三个主要深拉成形工艺参数对残余应力的影响,建立了液氮生物容器圆筒件数值模型,通过Box-Benhnken响应面法设计试验方案,采用Abaqus软件进行数值模拟计算。结果表明:试验工况下圆筒件最大残余应力均发生在直筒上端部位和直筒与封头连接处,封头上残余应力分布及大小基本相同;压边力越小时,残余应力越大,也越容易出现褶皱,而凹模圆角半径越大时,残余应力越大,但是越不容易出现褶皱,摩擦系数对残余应力影响不大。

Deep drawing has been widely used in the manufacture of pressure vessels for its advantages of simple manufacturing process and high manufacturing efficiency,but the stainless steel cylinder formed by this method is easy to produce residual stress,which affects the quality of liquid nitrogen biological containers.In this paper,in order to study the influence of three main deep drawing process parameters such as blank holder force,friction coefficient and die fillet radius on residual stress,a numerical model of liquid nitrogen biological container cylinder is established.The test scheme is designed by Box-Benhnken response surface method,and numerical simulation calculation is carried out by Abaqus software.The results show that the maximum residual stress of the cylinder occurs at the upper end of the cylinder and at the junction between the cylinder and the head,and the distribution and magnitude of residual stress on the head are basically the same.The smaller the blank holder force,the greater the residual stress and the easier it is to wrinkle.The larger the die fillet radius,the greater the residual stress but the harder it is to wrinkle.Friction coefficient has little effect on residual stress.