共查询到19条相似文献,搜索用时 171 毫秒
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首先阐述了弯曲成形回弹模拟的方法及其一步逆成形法的基本原理。通过采用一步逆成形法来获得弯曲成形后的应力分布,然后利用LS~DYNA隐式求解器对卸载回弹过程进行了模拟。最后将该方法分别应用到无约束圆柱弯曲成形和卡车纵梁弯曲成形的回弹模拟中,并将模拟结果与实验结果进行了比较,比较的结果表明,该方法可以有效地预示出弯曲成形的回弹量。 相似文献
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首先阐述了弯曲成形回弹模拟的方法及其一步逆成形法的基本原理.通过采用一步逆成形法来获得弯曲成形后的应力分布,然后利用LS-DYNA隐式求解器对卸载回弹过程进行了模拟.最后将该方法分别应用到无约束圆柱弯曲成形和卡车纵梁弯曲成形的回弹模拟中,并将模拟结果与实验结果进行了比较,比较的结果表明,该方法可以有效地预示出弯曲成形的回弹量. 相似文献
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对挤压弯曲成形大口径弯头的变形过程进行了有限元模拟分析.对压扁工序和弯头成形工序分别进行建模和模拟,并对模拟结果进行了应力、应变分析和成形过程载荷分析.对影响弯头成形的关键区域--内弧和外弧区域进行了速度场分析.将模拟成形后的弯头与工厂实际生产的弯头相对比,成形情况良好. 相似文献
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考虑热物性能参数随温度变化的因素,以硅为对象进行激光弯曲模拟和试验,借助APDL语言编写激光弯曲成形的仿真程序,对单脉冲作用过程进行模拟,以得到单点脉冲周期内的温度分布;并采用NiCr/NiSi合金薄膜热电偶对单脉冲作用过程中的温度分布进行测量,对比上述的温度模拟与测量结果,修正硅材料的激光综合吸收系数。采用有限元分析软件实现了硅片的脉冲激光弯曲成形的仿真和模拟,并对多次连续扫描的模拟结果与硅片弯曲试验结果进行对比,验证了仿真程序的有效性,为硅片的激光弯曲成形提供了理论与试验依据。 相似文献
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《机械工程与自动化》2020,(5)
弯曲成形是材料弹塑性变形的结果,这一过程中存在着高度的非线性。基于大变形的弹塑性变形理论,借助于ABAQUS软件处理非线性问题的优势,对U形件弯曲成形过程进行模拟分析,在实际生产中具有一定的应用价值。 相似文献
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鉴于零件对材料增厚及表面质量没有严格要求,采用无压边拉深来完成零件螺旋台阶面的成形,不仅模具结构简单,而且材料利用率高.围绕零件成形难点部位,以特征点的形式详细分析了拉深成形过程中特征区域的应力、应变、厚度和成形极限等模拟结果.在分析拉深工序的基础上,进一步对零件进行多工步模拟分析.结合等效塑性应变、厚度分布及成形极限等信息分析了其它工步作用过程中的变形特点.通过数值模拟结果与实际冲压结果的对比,验证了多工步数值模拟结果的有效性. 相似文献
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DIRECT AND ADAPTIVE SLICING ON CAD MODEL OF IDEAL FUNCTIONAL MATERIAL COMPONENTS (IFMC) 总被引:3,自引:0,他引:3
Xu Daoming Jia Zhenyuan Guo Dongming Key Laboratory for Precision Non-traditional Machining Technology of Ministry of Education Dalian University of Technology Dalian China 《机械工程学报(英文版)》2005,18(1):139-144
A brand new direct and adaptive slicing approach is proposed, which can apparently improve the part accuracy and reduce the building time. At least two stages are included in this operation: getting the crossing contour of the cutting plane with the solid part and determining the layer thickness. Apart from usual SPI algorithm, slicing of the solid model has its special requirements. Enabling the contour line segments of the cross-section as long as possible is one of them, which is for improving manufacturing efficiency and is reached by adaptively adjusting the step direction and the step size at every crossing point to obtain optimized secant height. The layer thickness determination can be divided into two phases: the geometry-based thickness estimation and the material-based thickness verifying. During the former phase, the geometry tolerance is divided into two parts: a variety of curves are approximated by a circular arc, which introduces the first part, and the deviation error between the contour 相似文献
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借鉴自由曲面逆向工程中扫描步长自适应优化的思想,提出了基于CAD信息的线扫描步长自适应优化方法。基于曲线拟合容差开发了圆弧图元线扫描步长自适应优化算法;基于等线段长开发了直线图元线扫描步长自适应优化算法;基于图元间的拓扑结构归纳了区域线扫描步长自适应选取准则。用弹性臂薄片零件的尺寸检测实验对基于CAD信息的线扫描步长自适应优化方法的检测精度和扫描数据量进行了分析。实验结果表明,该方法能提高检测系统的检测精度,提高线扫描的扫描效率,减少扫描数据量。 相似文献
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冲压成形CAE技术中接触摩擦计算的新方法 总被引:14,自引:2,他引:12
以显式有限元仿真技术为背景 ,讨论冲压成形中模具与工件接触摩擦界面的计算问题 ,提出了一种新的接触界面计算方法 ,并应用非线性摩擦定律来计算作用在工件上的摩擦力。为避免用于计算接触力的罚函数法中的罚因子影响显式仿真算法的稳定性 ,采用了局部质量密度因子来抵消罚因子的负面影响。仿真计算实例结果验证了本方法的正确性以及在可靠性和计算速度方面的明显提高。 相似文献
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自由曲面工件多点连续成形方法 总被引:7,自引:1,他引:6
为了实现自由曲面工件的高效率、低成本制造,分析与比较常用的柔性成形方法;从成形过程的连续性考虑,将柔性成形分为分段成形与连续成形;从变形区大小考虑,又划分为点成形、面成形与线成形等不同类型。比较不同成形方式的优点与缺点,指出自由曲面工件的高质量、高效率成形是亟待解决的技术难题。提出基于连续线成形方法的自由曲面工件高效、柔性成形思路;并提出采用多点调整式柔性辊的多点连续成形技术方案;探讨多点连续成形技术的基本原理、关键技术及主要特点。运用具有多个控制点的挠性轴设计出可弯曲、可调整的柔性辊,开发出多点卷板成形试验装置。多种三维曲面板类件的连续成形试验结果表明,多点连续成形技术能够解决自由曲面工件的高效加工难题。 相似文献
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板材软模成形是板材和柔性传力介质耦合变形过程,存在板材和刚性模具及板材和柔性传力介质两种类型的界面接触。采用罚函数法计算接触力,推导了Mindlin轴对称壳单元和实体单元两种不同单元类型之间接触摩擦的有限元列式。采用静力显式的时间积分方法,通过控制载荷步长保持接触状态稳定。粘弹塑性软模材料的板材变形数值算例表明该算法是有效的。该算法也适用于其他类型软模材料的板材变形接触摩擦问题的处理。 相似文献
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In one step inverse finite element approach, an initial blank shape is normally predicted from the final deformed shape. The final deformed shape needs to be trimmed into a final part after stamping, the trimmed area, therefore, needs to be compensated manually before using one step inverse approach, which causes low efficiency and in consistency with the real situation. To solve this problem, one step positive approach is proposed to simulate the sheet metal stamping process. Firstly the spatial initial solution of one step positive method is preliminarily obtained by using the mapping relationship and area coordinates, then based on the deformation theory the iterative solving is carried out in three-dimensional coordinate system by using quasi-conjugate-gradient method. During iterative process the contact judgment method is introduced to ensure that the nodes on the spatial initial solution are not separated from die surface. The predicted results of sheet metal forming process that include the shape and thickness of the stamped part can be obtained after the iterative solving process. The validity of the proposed approach is verified by comparing the predicted results obtained through the proposed approach with those obtained through the module of one step inverse approach in Autoform and the real stamped part. In one step positive method, the stamped shape of regular sheet can be calculated fast and effectively. During the iterative solution, the quasi-conjugate-gradient method is proposed to take the place of solving system of equations, and it can improve the stability and precision of the algorithm. 相似文献