80MN快锻液压机结构动态特性分析

Dynamic characteristic analysis of a high speed hydraulic press

针对高频次锻造工况下作业的80MN快锻液压机结构动态特性要求高等问题,基于ANSYS动力学分析的原理,并考虑到动力学分析需要占用的计算机资源大,简化了活动横梁装配,忽略了导向架,对活动横梁与立柱接触结合部x方向采用耦合连接,活动横梁底面覆盖一层目标单元,锻件顶面覆盖一层接触单元,形成接触对;活动横梁的初始速度设置为15 mm/s,加速度设置为537 mm/s2,加速度的加载采用阶梯加载方式,同时考虑结构预紧力对结构分析的影响,建立了其结构动力学分析的有限元模型,进行了结构在动载荷作用下的动力学响应分析计算,获得了液压机结构的动应力分布规律和变形分布规律。研究结果表明,结构动态最大位移值约为最大静态位移值的2倍,结构在动态载荷下的应力也约为静态的2倍,发现了结构刚度薄弱环节,为在设计过程中更加合理地布置结构刚度,提供了理论依据。

Aiming at the dynamic characteristics of 80MN hydraulic press structure under very high working frequency,the finite element model for the dynamic analysis of 80MN hydraulic press structure was established,based on the principle of the ANSYS dynamics analysis and considering large computer resources needed for structure dynamic analysis.In this FEM model,the movable beam assembly was simplified,the leading truck was ignored,the joint between the movable beam assembly and the column was coupled in x-direction,the bottom of the movable beam was covered by object elements,the top surface of forging was covered by contact elements,the initial speed of the movable beam was set 15 mm/s,and the initial acceleration of it was set 537 mm/s^2,the acceleration was loaded in step.The structure pre-tightening force was considered in the FEM model.The structural response under the dynamic load was successfully calculated.The stress distribution of the hydraulic machine under dynamic loads and deformation distribution was obtained.Simulation results show that the stress under dynamic loads is about twice of the static stress value and the maximum dynamic displacement is also about the maximum static displacement,and the weak stiffness location is also found.This provides a theory basis for more reasonable stiffness arrangement of the structure in design stage.