共查询到19条相似文献,搜索用时 453 毫秒
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针对采用有限元模拟方法对连续拉深成形模拟过程中,"后续模拟过程不能继承上一步模拟结果,每次模拟均为独立流程,与连续拉深成形实际过程不符"的问题,对有限元连续拉深模拟过程、参数设置、前后处理等方面进行了研究,提出了基于ANSYS LS_DYNA的连续正反拉深的成形模拟方法和分析流程,通过采用APDL语句控制分析过程及相关参数设置,做到了参数化和通用化。提出并总结了模拟连续成形的技术关键点(该方法可应用于连续冲压成形有限元数值模拟,使连续成形可继承前步模拟结果),并在此基础上进行了后续的反拉深成形有限元模拟分析,做到了分析模拟的连续性。基于这种方法对典型正反拉深筒形制件进行了成形模拟。研究结果表明,该数值分析思路和方法可以实现多次连续冲压成形分析模拟,结果与实际情况较为符合。 相似文献
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对汽车桥壳本体内高压成形工艺进行有限元模拟研究,基于弹塑性有限元法建立了数学模型并进行了动力显式有限元分析求解,对成形工艺进行分析,研究了内压和轴向进给等主要工艺参数对形成量的影响。 相似文献
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Prediction and prevention of side-wall wrinkling are extremely important in the design of tooling and process parameters in sheet metal forming processes. The prediction methods can be broadly divided into two categories: an analytical approach and a numerical simulation using finite element method (FEM). In this paper, a modified energy approach utilizing energy equality and the effective dimensions of the region undergoing circumferential compression is proposed based on simplified flat or curved sheet models with approximate boundary conditions. The analytical model calculates the critical buckling stress as a function of material properties, geometry parameters and current in-plane stress ratio. Meanwhile, the sensitivities of various input parameters and integration methods of FEM models on the prediction of wrinkling phenomena are investigated. To validate our proposed method and to illustrate the sensitivity issue in the FEM simulation, comparisons with experimental results of the Yoshida buckling test, aluminum square cup forming and aluminum conical cup forming are presented. The results demonstrate excellent agreements between the proposed method and experiments. Our model provides a reliable and effective predictor for the onset of side-wall wrinkling in sheet metal forming processes. 相似文献
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固体颗粒介质板材成形工艺是采用固体颗粒微珠代替刚性凸(凹)模(或弹性体、液体)的作用对板材拉深成形的新工艺。选用非金属固体颗粒介质——GM颗粒作为研究对象,以固体颗粒介质在高应力水平下的体积压缩试验和摩擦强度试验为基础,应用散体力学理论中扩展的Drucker-Prager线性模型构建固体颗粒介质有限元材料模型。以具有非轴对称性的方盒形件为代表,进行固体颗粒介质成形工艺的有限元模拟,研究成形过程中板材的流动特征和壁厚分布规律。工艺试验成功得到方盒形零件,将加载曲线、成形过程变形特征和壁厚分布曲线与数值模拟结果比对较为吻合。分析表明,采用以散体力学为基础建立的固体颗粒介质材料模型进行工艺模拟,能够得到与试验较为接近的变形特征和力能参数,可以应用于制定工艺方案的依据,为该技术在板材成形中的应用起到指导和借鉴作用。 相似文献
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Jianjun Wu Xin Wu Liangcai Deng Hakim Naceur 《The International Journal of Advanced Manufacturing Technology》2014,71(5-8):843-855
For some shortcomings in the use of standard radial length development in the blank development for forming sheet metal parts, an improved radial length normal spreading approach considering outside normal direction is developed to resolve blank development in sheet metal forming. Moreover, a comprehensive spreading method, which combines radial length normal spreading and orthogonal length development method, is presented in this paper to avoid the overlapping problem which happens sometime in the spreading process related to severely curved sheet parts. To deal with holes and gaps which exist in some sheet metal parts, dummy elements are used to calculate the intercepting line’s length precisely. Finally, a multistep spreading and merging strategy is adopted to handle some special sheet metal parts with vertical free edges that should be jointed or not. Through practical applications, the effectiveness and the usefulness of this approach are evaluated, and the unfolded result is more reasonable; meanwhile, the obtained blank shape should be a better initial guess in the application of the so-called one-step quick analysis for sheet metal forming simulation. 相似文献
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Wanjin Chung Bongsu Kim Seongwon Lee Hoyeun Ryu Mansoo Joun 《Journal of Mechanical Science and Technology》2014,28(1):237-243
In this paper, finite element prediction of sheet metal forming process is investigated using solid elements. A three-dimensional rigidviscoplastic finite element method with linear tetrahedral MINI-elements is employed. This technique has traditionally been used for bulk metal forming simulations. The solid element approach with remeshing capability is applied to simulating a plate metal forming process to reveal its possible problems. The similar approach is also applied to a typical sheet forming process. Both single- and double-layer finite element mesh systems are studied, with particular attention to their effect on the deformed shape of the workpiece and thickness variation of a cold sheet forming process. The procedure is applied to the well-known problem of the NUMISHEET93 international benchmark. The resulting predictions are compared with experimental observations found in the literature, and good agreement is noted. 相似文献
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Zemin Fu Jianhua Mo Wenxian Zhang 《The International Journal of Advanced Manufacturing Technology》2009,45(5-6):448-458
A mathematical model of springback radius was developed with dimensional analysis and orthogonal test. With this model, the punch radius could be solved for forming high-precision semiellipse-shaped workpieces. With the punch radius and other geometrical parameters of a tool, a 2D ABAQUS finite-element model (FEM) was established. Then, the forming process of sheet metal multiple-step incremental air bending was simulated with the FEM. The result showed that average errors of the simulated workpiece were +0.68/?0.65 mm, and provided the process data consisting of sheet feed rate, punch displacement and springback angle in each step. A semiellipse-shaped workpiece, whose average errors are +0.68/?0.69 mm, was made with the simulation data. These results indicate that the punch design method is feasible with the mathematical model, and the means of FEM simulation is effective. It can be taken as a new approach for sheet metal multiple-step incremental air-bending forming and tool design. 相似文献
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针对大型板材的冲压成形问题,提出了一种离散多点成形工艺。介绍了此工艺中模具及柔性杆的结构。与已有的多点成形工艺——杆系柔性成形和活络方形压头非对压技术相比,离散多点成形工艺在大型板材成形过程中有其自身的优势。 相似文献
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基于有限元逆算法的板料成形模拟拉深筋的灵敏度优化 总被引:3,自引:0,他引:3
基于有限元逆算法和灵敏度优化的BFGS (Broyden-Fletcher-Goldfarb-Shanno)算法,提出一种以成形极限曲线和起皱极限曲线作为目标函数,优化拉深成形中的拉深筋位置和大小的拉深筋灵敏度优化算法。优化算法综合考虑冲压件成形过程中起皱和破裂对成形性的影响因素,比只考虑板厚变化更能准确地反映板料的成形性,而且基于逆算法的灵敏度优化算法计算速度很快,可以应用于大型复杂冲压件的工艺参数优化过程模拟。通过两个典型的零件验证了该算法的优化结果符合实际工艺。 相似文献