文档介绍：湘潭大学毕业论文
摘要
综述了国内外在板料数值模拟方面的发展和现状,分析了板料成形研究的技
术特点,指出了应用研究中尚待解决的一些关键技术问题。
对板料成形中动力显式计算方法进行了全面系统的分析。对动力显、隐式算
法作了技术上的比较,分析了动力显式方法在板料成形模拟上的优势。分析论述
了板料成形非线性问题的显式求解方法,对动力显式计算中的相关理论和技术问
题作了较深入的研究和讨论。从能量分析角度讨论了动力显式算法中的质量放大
和速度放大问题。推导了具有一般屈服函数形式的弹塑性速率的本构关系,给出
了板料在 Hill 塑性各向异性屈服模型下本构关系的具体形式,导出了以Lankfor d
试验参数形式表达的平面应力形式下的弹塑性本构方程显式表达,讨论了塑性各
向异性对成形的影响。
根据实际加工工艺过程的特点,建立了抛物面零件成形分析的有限元计算模
型,利用通用的动力显式计算软件实现了这种加工方式的计算机模拟,有效地解
决了加工中这类非连续的准静态问题。就模型的建立、成形工艺的编排、单元划
分、压边的模拟、冲压速度的选择、接触的定义进行了详细的阐述和数值实验。
研究了如何利用有限元软件 DYNAFORM 对抛物面零件进行板料冲压成形
过程分析的计算机模拟技术,模具的形状特别是圆角半径能被修改以达到生产外
形和精度符合需要的零件,并且合理选择机械力学适合的材料。比较全面的探讨
了动力显式算法程序在预测应力、应变,判断拉裂与起皱现象。通过有限元数值
模拟选择选择合理模具几何参数和合适的力学性能材料,本文所做的工作对工程
实践有很好的指导意义和实用。
关键词:DYNAFORM; 有限元; 数值模拟;
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湘潭大学毕业论文
ABSTRACT
The state of arts on numerical simulation Of sheet forming processes is
summarized . The techniques related in sheet forming simulation is systematically
analyzed and some key problems which are not yet solved well in the current
applications are point out.
Dynamic explicit approach in sheet forming simulation is presented . Technical
differences between implicit and explicit approach pared and advantages of
explicit method over implicit one are discussed. Nonlinear explicit algorithms for
sheet forming simulation are discussed in detail and also the punch velocity scaling
and mass scaling techniques are studied from view point energy.
A rate form elastic-plastic constitutive equation with arbitrary yield function and
its specific form under Hill’s plastic anisotropy yield criterion are developed . The
explicit express of constitutive matrix in term of Lankford parameters in plane stress
form is also given . The effects of plastic anisotropy on formability and earring are
examined.
A Finite element analysis model has been established to simulate the deep
drawing processes and dynamic explicit FEA code-DYNAFOM is employed to
analyze this discontinuous quasi-static process essfully . Practice experiment