【作者】 齐会文；

【导师】 徐吉生； 孙惠学；

【作者基本信息】 燕山大学 ， 工程力学， 2005， 硕士

【摘要】 本文利用理论解析的研究手段,分析了盒形件法兰变形区和悬空侧壁区的应力场。在假设盒形件圆角区剪应力零线上质点的变形规律与相应的轴对称拉深件相同的前提下,引用盒形件法兰变形区和悬空侧壁区应力的理论解析,为拉深成形中的起皱、破裂预测等问题提供了理论依据。并以此为基础分析了起皱和破裂产生的原因、特点、影响因素、以及如何控制等。 以有限元分析软件 ANSYS/LS-DYNA 为研究手段,通过数值模拟的方法,研究了方盒形件的拉深成形过程。根据方盒形件的特点,本文建立了包括板料、凸模、凹模以及压边圈在内的三维有限元分析模型。考虑到对称性,取四分之一模型进行有限元模拟,由于凸模、凹模以及压边圈变形都很小,故将其视为刚体。通过对方盒形件拉深成形过程的模拟,得出了拉深不同深度的应力场、应变场分布以及厚度变化、节点位移矢量图;通过模拟分析不同压边力、不同冲压速度、不同摩擦系数、不同凹模圆角半径、不同凸模圆角半径、不同转角半径等各种参数,得出了比较合理的方盒形件拉深过程中的工艺参数和力能参数。 模拟结果表明,有限元数值模拟方法可以节省大量的费用和时间,能够为拉深工艺设计及模具设计提供重要的参考依据,不失为工程分析的一种有效数值模拟工具。更多还原

【Abstract】 In this paper, the stress field of square box part is studied by theoretical analysis. The stress of flange and hanging side wall has been derived based on assumption that the deformation rule of shear stress zero-line of rectangular box part is assumed to be identical to that of corresponding axisymmetry part. That lays the foundation of the prediction on wrinkling and fracture of the rectangular box part during drawing. The numerical simulation of forming process of the square box part is carried out using the explicit non-linear finite-element code ANSYS/LS-DYNA3D. A three-dimensional finite-element model, which includes plate, punch, die and holder pad, is established to simulate the drawing process based on the characteristics of the square box part. A quarter model is used to simulate for the reason of symmetry. Punch, die and holder pad are regarded as rigid body because of little deformation. Stress field, strain field and the variation of thickness at different depth of drawing are obtained. Also the vectograph of node displacement is gotten. Reasonable technology parameters are acquired by simulating with different blank holder force, different velocity of punch, different coefficient of friction, and different round-cornered of die. The numerical simulation result is competent, and can provide important reference for the design of die and drawing technology. It is showed that finite-element method can save much time and cost. It is a useful tool for engineering analysis.更多还原