板料冲压成形及回弹有限元数值模拟分析研究

【作者】 江煜煌；

【导师】 樊黎霞；

【作者基本信息】 南京理工大学 ， 机械设计及理论， 2007， 硕士

【摘要】 板料冲压成形是一种先进、优质、高产、低消耗、低成本的加工工艺方法，在众多生产领域中得到广泛的应用。同时，板料冲压成形是一个同时包括几何非线性、材料非线性和边界条件非线性等问题的复杂的弹塑性大变形力学过程。因此对于复杂的冲压成形件，仅靠工程师的经验公式设计出来的模具往往不能满足产品的技术要求。随着计算机技术的迅速发展，设计师开始采用计算机模拟技术来指导模具的设计。大量实践证明，有限元法是进行冲压成形过程计算机仿真最合适的数值模拟方法，合理的使用有限元数值模拟技术可以显著地提高模具设计质量，缩短模具设计周期。本文即是通过有限元数值模拟方法对某汽车冲压成形件进行冲压成形及回弹过程的数值模拟试验，研究一些关键参数对成形过程及回弹结果的影响规律。在冲压成形数值模拟部分主要研究了拉延筋形状及布置形式、坯料初始形状、网格单元属性、坯料与模具及压边圈之间摩擦系数、网格自适应技术对成形结果的影响，并得出这些关键因素对成形结果的影响规律。回弹是在实际生产中引起冲压件尺寸不合格的主要因素之一，回弹计算结果的准确性和收敛性也一直是回弹数值模拟的难点。本文详细介绍了运用LS-DYNA软件进行回弹模拟的全部过程，通过数值模拟试验分析了模具间隙、板料厚度及坯料初始网格数量对回弹量大小的影响，得到了这三个因素对最终回弹结果的影响规律。更多还原

【Abstract】 The sheet metal forming is an advanced, high quality, efficient, lowconsumption and low cost manufacture technology. It has been widely appliedin all kinds of mechanical industry. At the same time, sheet metal formingis a complicated elastic and plastic mechanical process which includesnon-liner problem of material models, boundary condition, element algorithmand contact handling methods etc. So when faced complicated accessories, thedie designed by the engineer only through traditional experience and formulassometimes can not reach the technical demand of products.With the development of computer technology, engineers begin to usecomputer simulation technology to aid the tool’s design. Lots of practicesprove that finite element method is the best way to simulate the process ofsheet metal forming. Using the technology of CAE can remarkably improves thequality and shortens the cycle of die design. In this paper, numericalsimulations of sheet metal stamping and springback process about an automobilepanel are investigated and the rules of some selected processing parametersare found through comparatively deep study.On the section of stamping simulation, the infection to the result aboutthe distribution of drawbead, the original sharp of the blank, the attributeof the meshing element, the friction coefficient between the blank and thedie, the techno]ogy of adaptive meshing are mainly investigated. The effectingrules of these processing parameters above are found.The phenomenon of Springback is one of the main effects for the geometryof the stamping parts. The accuracy and the convergence of the simulation arealso the key points for the springback. In this paper, the whole process abouthow to deal with springback problem using the software of LS-DYNA is introducedin detail. And the infection to springback result about the clearance betweenthe up-die and the low-die, the thickness of the blank and the demand amountof the meshing element for the blank are analyzed through computer simulationtest. At last, the effecting rules of these processing factors to thespringback result are found.更多还原