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薄壁锥形件旋压成型中应力、应变场的有限元分析 总被引:1,自引:1,他引:0
应用大型有限元分析软件ANSYS10.0建立了薄壁锥形工件旋压成形的有限元模型,以显式动力学求解器LS-DYNA为基础模拟了其旋压成形过程,分析了工件成形过程中的变形和应力特点,研究了应力和应变等因素对工件成形质量的影响规律。结果表明:应力、应变图显示了成形过程中工件应变和应力的分布特点与规律,为解决工件旋压成形过程中的问题提供了依据;旋压数值模拟有助于发现旋压变形中存在的旋压成形中容易产生断裂、翻边、褶皱和失稳等缺陷问题及产生的原因;旋压力振荡和减薄率过大是工件旋压断裂的主要因素;在旋压工艺中可以通过优化减薄率、转速和进给量等工艺参数有效控制锥形工件旋压成形质量;分析结果对于旋压模具的优化设计和旋压工艺参数合理选择提供了可靠的理论基础。 相似文献
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板料变形三维数字散斑应变测量分析系统研究 总被引:2,自引:0,他引:2
针对板料变形中应变检测的常规方法和传统方法存在的不足,通过数字散斑相关方法、计算机双目视觉理论和材料力学理论分析了试件表面变形前后的散斑图像,来动态跟踪试件表面上几何点的运动并得到三维位移场,在此基础上计算得到试件的三维应变场.基于此原理开发了XJTUDIC三维数字散斑动态应变测量分析系统.应用带孔铝质制件进行了单向拉伸实验.测量结果表明,该系统能较好的反映板料变形过程中的三维应变状态,较好的测量试件表面的三维轮廓,直观再现工件表面的变形场、应变场和成形极限图(FLD),对于需要测量的关键点可以实现重点跟踪,动态测量出该点在任意时刻任意位移的应变.该系统可以应用到不同的力学测量现场. 相似文献
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基于立体视觉的坐标网格分析法 总被引:4,自引:0,他引:4
坐标网格分析法作为一种物理模拟技术 ,已在金属塑性成形的生产中被广泛应用 ,但传统的手工测量方法存在工作量大和精度低的缺点。该文针对板料成形中常用的三维圆形坐标网格系统 ,提出一种新的基于图像处理和立体视觉技术的网格应变自动测量分析方法 ,并开发了相应软件 ,成功地测绘出变形工件的应变等值线图和板料成形极限图。实验结果表明 ,该方法可以使板料应变的测量速度和精度均得到提高 相似文献
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基于ABAQUS/Explicit平台,建立了双旋轮筒形件流动旋压成形有限元数值模拟模型,分析了DP800高强钢筒形件流动旋压成形过程的应力应变分布规律,并研究了旋轮成形角、旋轮圆角半径、旋轮进给比和壁厚减薄率4个关键工艺参数对DP800钢筒形件流动旋压力的影响。结果表明:等效应力和等效应变的最大值出现在旋轮与坯料接触区,已成形区域的应力均匀;工件外表面的等效应变均大于工件内表面等效应变,并沿着厚度方向逐渐减小;各旋压分力大小顺序为:径向旋压力轴向旋压力切向旋压力;随着圆角半径、旋轮进给比、壁厚减薄率的增大,各向旋压分力和总旋压力都呈增大趋势;随着成形角的增大,轴向旋压力和切向旋压力呈增大趋势,但径向旋压力和总旋压力呈先减小后增大趋势。 相似文献
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汽车板冲压成形表面波纹度对零件涂装后的鲜映性有着重要的影响,而鲜映性直接反映汽车外观质量。为明确波纹度影响因素,测量准确可靠的试验数据,基于gom在线应变测量系统,通过BUP1000板材综合成形试验机对典型汽车外板进行马克杯冲压,分析了冲压后不同变形量、试样表面检测方向及试样冲压速度等因素对试样表面波纹度的影响。研究结果表明:随着冲压后试样表面变形量的提高,波纹度结果几乎呈线性增加。试样在0.5~3 mm/s的冲压速度下,表面波纹度变化无明显规律,因此冲压速度对表面波纹度影响不大。轧向与横向检测结果表明,纵向波纹度稍低于横向波纹度结果。 相似文献
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Numpon Mahayotsanun Sripati Sah Jian Cao Michael Peshkin Robert X. Gao Chuan-tao Wang 《International Journal of Machine Tools and Manufacture》2009,49(7-8):634-644
In-situ stamping process monitoring plays a critical role in enhancing productivity and ensuring part quality in sheet metal stamping. This paper investigates the realization of two sensing methods to create a tooling-integrated sensing system: mutual inductance-based displacement measurement for sheet draw-in, and distributed contact pressure measurement at the tool–workpiece interface. The two sensing systems are complementary in nature, and together, they significantly enhance the on-line observability of the stamping process. The performance of the draw-in sensor was evaluated using numerical simulations and experiments in a small-scale and a large-scale lab setup, and its effectiveness has been confirmed under the presence of wrinkled sheet. To study the spatial and temporal variations of the tool–workpiece contact pressure in a stamping operation, experiments were conducted on a customized panel stamping test-bed with an array of thin-film force sensors embedded below the die flange and die cavity. The force sensor data were then numerically interpolated to form the contact pressure distribution across the tool–workpiece interface, based on the thin plate spline (TPS) method. Comparison between the interpolated pressure obtained from the surface generation techniques and direct measurement using redundant sensors and a press mounted load cell confirms the validity of the new contact pressure sensing method. The integrated sensing technique provides insight into the stamping process by quantifying process variations and providing a reference base for process control to reduce product disparities. Additionally, new product and process designs can be created based on the quantified and referenced variations. 相似文献
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通过实例介绍了应用Pro/E的Mechanica模块完成冲压模具组件力学分析的方法,对模具组件的分析结果作了必要的评价,并将组件分析的结果与单件分析的结果进行了比较,分析了造成结果误差的主要原因在于约束和连接的设置。例如:组件中各模板之间设置为接触界面而非单件分析时的平面约束;各模板的连接设置为螺钉连接、销钉约束而非单件分析时的固定约束等。这为更准确地预测模具组件的应力和应变提供了一种方便、高效的方法。 相似文献
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接触热阻是影响热冲压过程中热能传导的一个重要因素,而零件不同区域的温差则直接影响热冲压的回弹,因此,获得准确的接触热阻数值对提高热冲压回弹仿真的精度具有重要意义。基于稳态法设计了22MnB5板件与Cr7V模具钢接触热阻的测量实验,推导出接触热阻的计算公式;并按照实验方法搭建了实验平台,获得了不同压强下两者的接触热阻值;最后拟合了接触热阻与压强的关系方程。将关系方程带入某B柱的热冲压回弹仿真中,与原始仿真对比发现,改进后的仿真结果与实际实验值较为接近,证明获得准确的接触热阻与压强的关系方程可提高硼钢板热冲压回弹的仿真精度。 相似文献
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汽车工业中大型覆盖件冲压生产对冲压设备提出了越来越高的要求,促进了大型压力机技术迅速发展。数控拉伸垫是大型压力机的关键部件。在压力机拉延工件时,依据板料成形工艺要求,通过拉伸垫实时控制压边力。本文在研究产生压边力的方案基础上,对应液气式数控拉伸垫的控制曲线,对其工作原理进行了分析,着重分析了预加速运动和压边力控制过程。对液压系统进行了静态计算以便主要元件选型,并对辅助动力系统和系统产生的热量进行了计算。 相似文献
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Comparison of different analysis models to measure plastic strains on sheet metal forming parts by digital image processing 总被引:2,自引:0,他引:2
The principal strains of sheet metals and their limitations while forming can be obtained by using a strain measurement system. A strain measurement may employ one of two different approaches: namely the total least square optimization method or the multiple regression analysis (MRA) method. With both methods plastic strains of deformed parts are calculated based on the non-deformed reference configuration designated by a circle and the deformed configuration, which is a curve-fitting ellipse. In the MRA method, the mathematical formula is simpler reducing the required computations than that of the total least square optimization method. While the formula has a greater margin of error, this margin proves less than significant in the practical application of the method’s results.Information from the results of a strain measurement system can be used to determine the sheet metal’s formability and strain path allowing engineers to determine at which point, the sheet metal will crack. They can then change the thickness and the material of the sheet metal, or modify its shape accordingly to maximize the metal’s efficiency. Strain measurement systems possess practical advantages in their actual application; they improve the quality of sheet metal being produced by minimizing defects in sheet metal during production. One industrial case study of fine stamping electronic part is discussed to demonstrate the proposed methodology. 相似文献
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