共查询到18条相似文献,搜索用时 109 毫秒
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薄层单元可有效地表征螺栓连接结合部,但要进行动力学分析及优化必须辨识出薄层单元参数。为此,在建立薄层单元参数与结合部动态特性关系的基础上,提出一种准确、高效辨识薄层单元参数的方法。通过分析薄层单元的刚度矩阵及本构方程,确定待辨识参数;采用拉丁超立方抽样方法选取参数样本,结合试验与有限元计算的模态参数建立目标函数,用响应面模型表征薄层单元参数与目标函数的关系,并评价模型精度;采用遗传算法在响应面模型基础上实现参数优化辨识。分别辨识均一材料和考虑结合面应力分布差异化材料的薄层单元参数,参数优化辨识后,试件的试验与有限元计算固有频率误差均不超过4%,证明了该辨识方法的有效性。 相似文献
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提出了一种基于反求理论的汽车碰撞安全性优化方法。为了提高有限元仿真在汽车安全性分析方面的准确性,通过有限元仿真与试验验证相结合的方法,利用反求技术求出材料的特性参数。将得到的特性参数应用于某种卡车驾驶室的相同材料,对驾驶室的结构参数进行优化。选取卡车翻滚时对驾驶员安全影响较大的参数作为优化目标,利用遗传算法对构造的多目标优化模型进行计算。通过计算结果可知,有限元仿真中默认的材料特性参数与试验结果有一定的差别,将试验得出的数据应用于优化中可以得到更准确的结果。 相似文献
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针对废铅酸蓄电池再利用的预处理过程,提出具有实际意义的振动式分选机的优化设计方法。首先,计算相关参数获得初始模型,借助ANSYS Workbench进行有限元分析,使其初步符合设计要求。其次,以减小质量、提高强度和提高第三阶固有频率为优化目标,选取关键尺寸参数为设计变量,通过中心复合试验设计方法选取合适的有限元分析样本点,利用最小二乘法拟合含交叉项的二次多项式,获得目标与变量的近似响应面数学模式,再运用遗传算法进行优化获得全局最优解。最后,对比有限元计算值与响应面计算值验证响应面法可行性。结果表明:减少质量5.9%,降低最大等效应力46.9%,提高第三阶固有频率30.1%,降低了优化计算量。 相似文献
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基于近似模型的拉延筋几何参数反求 总被引:16,自引:1,他引:16
引入响应面方法和遗传算法建立基于近似模型的拉延筋几何参数反求方法。首先以等效拉延阻力为设计变量,通过均匀拉丁方试验设计方法提取适当的设计参数样本构造响应面近似模型,并不断优化响应面模型,获取最优等效拉延阻力;然后以最优等效拉延阻力为约束条件,结合等效拉延阻力计算和小种群遗传算法反求拉延筋几何参数。整个反求过程采用等效拉延筋有限元模型进行仿真计算,避免有限元模型的网格重划分及由真实拉延筋模型引入的计算效率问题。数值算例表明,基于近似模型的拉延筋几何参数反求方法可在设计兴趣域内快速寻优,有助于加快模具设计进程,降低生产成本。 相似文献
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Blank shape design for a planar anisotropic sheet based on ideal forming design theory and FEM analysis 总被引:4,自引:0,他引:4
K. Chung F. Barlat J.C. Brem D.J. Lege O. Richmond 《International Journal of Mechanical Sciences》1997,39(1):105-120
A sequential design procedure to optimize sheet forming processes was developed utilizing ideal forming design theory, FEM analysis and experimental trials. For demonstration purposes, this procedure was used to design a blank shape for a highly anisotropic aluminum alloy sheet (2090-T3) that results in a deep-drawn, circular cup with minimal earing. All blank shape design methods require a certain number of iterations. However, the sequential procedure can be more effective than the other iterative methods based on FEM analysis in conjunction with experimental trials or on experimental trials alone. For this design demonstration, the anisotropic constitutive behavior of the 2090-T3 sheet was expressed using plastic potentials previously proposed by Barlat et al. The implementation of the anisotropic strain-rate potential in the ideal forming design code is also briefly summarized. 相似文献
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The deep drawing process, one of the sheet metal forming methods, is very useful in the industrial field because of its efficiency.
The limiting drawing ratio (LDR) is affected by many material and process parameters, such as the strain-hardening exponent,
the plastic strain ratio, friction and lubrication, the blank holder force, the presence of drawbeads, the profile radius
of the die and punch, etc. In order to verify the finite element method (FEM) simulation results of the LDR, the experimental
data are compared with the results of the current simulation. The influences of the process parameters such as the blank holder
force, the profile radius of the die, the clearance between the punch and the die, and the friction coefficient on the LDR
are also examined. The abductive network was then applied to synthesize the data sets obtained from the numerical simulation.
The predicted results of the LDR from the prediction model are in good agreement with the results obtained from the FEM simulation.
By employing the predictive model, it can provide valuable references to the prediction of the LDR under a suitable range
of process parameters. 相似文献
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MA Linwei MO Jianhua 《机械工程学报(英文版)》2008,21(1):31-35
Single-point incremental forming (SPIF) is an innovational sheet metal forming method without dedicated dies, which belongs to rapid prototyping technology. In generalizing the SPIF of sheet metal, the deformation analysis on forming process becomes an important and useful method for the planning of shell products, the choice of material, the design of the forming process and the planning of the forming tool. Using solid brick elements, the finite element method(FEM) model of truncated pyramid was established. Based on the theory of anisotropy and assumed strain formulation, the SPIF processes with different parameters were simulated. The resulted comparison between the simulations and the experiments shows that the FEM model is feasible and effective. Then, according to the simulated forming process, the deformation pattern of SPIF can be summarized as the combination of plane-stretching deformation and bending deformation. And the study about the process parameters' impact on deformation shows that the process parameter of interlayer spacing is a dominant factor on the deformation. Decreasing interlayer spacing, the strain of one step decreases and the formability of blank will be improved. With bigger interlayer spacing, the plastic deformation zone increases and the forming force will be bigger. 相似文献
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主要讨论了用有限元逆算法进行钣金展开计算的方法,并用方盒和叶片的展开设计算例验证了这种方法的有效性。同其它的展开算法相比,有限元逆算法是一种计算精度较高,计算时间短的数值模拟工具。 相似文献
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金属板料冲压成形的数值模拟 总被引:6,自引:0,他引:6
本文采用有限元动力显式算法模拟金属板料冲压成形的加工过程。四结点蜕化壳单元和刚体壳单元分别用来建立权和模具的有限元模型;更新Lagrange法和速率型本构关系被用来处理板料变形中的大应变和大转动;材料模型采用塑性各向异性屈服与等向强化模型;通过主从面模型定义板料和模具的接触,接触算法采用运动约束法,摩擦力用库仓定律计算;并利用动力松弛法对回弹过程进行了计算。模拟结果和实际零件比较,证明模型合理,算法稳定,结果可靠,具有良好的应用价值。 相似文献
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