液压蓄能器隔膜在动荷载下应力响应研究

Study of stress response of hydraulic accumulator′s diaphragm under dynamic load

应用有限元方法建立了液压蓄能器橡胶隔膜动荷载作用下的有限元模型.将蓄能器隔膜与钢壁封闭的曲面作为控制面,通过坐标在控制面内积分得到氮气腔的控制体积.控制体积内根据理想气体热力学方程可得氮气压力.假定橡胶为不可压缩、各向同性材料,选用Ogden超弹本构模型作为橡胶材料模型,并通过单轴拉伸试验确定了材料模型的参数.通过计算得出了蓄能器橡胶隔膜在氮气压力及油压的动荷载冲击下的变形和应力响应.从结果中分析出导致橡胶隔膜发生破坏的原因,对原橡胶隔膜的形状和尺寸进行了修改,并通过计算验证得出了满足材料强度的橡胶隔膜模型.

The finite element （FE ） method is applied to build the FE model of hydraulic accumulator＇s rubber diaphragm under dynamic load.Taking the surface closed by the accumulator＇s diaphragm and the steel cover as the control surface,the control volume of the nitrogen chamber can be got by integrating on the control surface.Inside the control volume,the nitrogen pressure can be obtained according to the thermodynamics equation of ideal gas. Assuming that the rubber is incompressible and isotropic material,Ogden＇s hyperelastic constitutive model is applied to the rubber material.The material parameters are determined by fitting the uniaxial tension test data.The deformation and stress response of the accumulator＇s rubber diaphragm under dynamic load caused by the nitrogen and oil pressure are given.The rubber diaphragm＇s rupture reasons are analyzed based on the experimental results.The new modified models with different shapes and section sizes are built, and the optimal rubber diaphragm model which satisfies the strength of material is determined by validation.