共查询到19条相似文献,搜索用时 343 毫秒
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目的研究采用浮动凹模工艺温精密成形圆柱斜齿轮时,不同凹模运动速度下齿轮力能参数和各种场量变化规律。方法结合浮动凹模原理和圆柱斜齿轮结构特点,利用Defrom-3D软件建立变形-传热耦合有限元模型,模拟圆柱斜齿轮采用浮动凹模温精密成形过程,分析不同凹模运动速度下的变形规律。结果通过模拟分析,得到了凹模运动速度不同时的温成形斜齿轮成形载荷特点、坯料流动速度场分布、等效应力-应变分布、温度场分布等规律。结论采用浮动凹模工艺成形圆柱斜齿轮,可以减小成形力,当凹模运动速度大于凸模下行速度时,齿轮成形性更好。 相似文献
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本文主要针对小齿轮件的花键和齿轮成形问题,以及直齿轮模具成型问题做出了工艺分析,并选取了3种不同的固定凹模柱塞模式和固定凹模约束分流模式等模具方案进行了分析,主要分析了在这几种不同的模具方案设计下,直齿轮模具成型效果以及物理性能,得出最佳的模具方案。 相似文献
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冷挤压组合凹模的失效主要是凹模内腔疲劳裂纹的出现,在模具设计的前期较为准确的估算出组合凹模的疲劳寿命是模具优化设计的前提.通过对组合凹模的应力分析后,采用Mises屈服准则的方法把凹模所受的多轴应力转化成单轴应力,再利用局部应力应变法找到了估算冷挤压组合凹模寿命的途径. 相似文献
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为降低热冲压凹模的生产成本和使用成本,基于板料热冲压数值模拟对凹模结构进行了拓扑优化设计.运用有限元软件ABAQUS建立热力耦合有限元模型,对高强钢板U形件的热冲压成形和淬火过程进行了数值仿真.提取凹模与板料间关键工况下接触应力作为凹模拓扑优化的外在载荷,建立约束凹模结构关键区域节点位移的体积最小化拓扑模型,对热冲压凹模结构进行拓扑优化设计,最终实现结构减重20%,且优化后凹模的变形和应力与优化前的结果相差甚微.研究内容对热冲压过程数值模拟和模具结构拓扑优化研究具有一定参考价值. 相似文献
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张万喜 《高分子材料科学与工程》1996,12(6):135-138
从分维理论出发,讨论了聚合物在辐射交联反应中裂解度(P)与辐照剂量(R)间的关系。发现分维参数与聚合物内聚能密度密度(Ec)的表征分子链运动的参数分子链横截面积(Ap)之间有一一对应的关系。建议用方程Ap=(1/D-0.44)/0.009Ec计算聚合物的Ap值。用本方法计算出的Ap值与文献值较一致。 相似文献
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目的 在内高压成形过程中,合模力加载不合理不仅会导致模具寿命降低,而且容易引起管件截面精度超差,需探究合模力对管件截面尺寸的影响以改善这一缺陷。方法 以低碳钢和铝合金变径管为例,采用内高压成形实验与数值模拟的方法,在两种不同的加载条件下分析合模力对管件截面尺寸精度的影响规律。结果 变径管内高压成形时,模腔上、下侧的等效应力高于左、右侧,模腔顶部的径向位移最小,分型面附近的径向位移最大。模腔在合模力的作用下被压扁,导致卸载内压和合模力后管件截面竖直方向的直径始终小于水平方向,存在一定的不圆度。SAPH440低碳钢和6063铝合金变径管的截面最大不圆度分别为0.27%和0.26%。结论 在内高压成形过程中,合模力对截面精度的影响不可避免,需通过增大模具尺寸或采用可变合模力的加载方式以减小其影响。 相似文献
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Rong‐Tyai Wang 《中国工程学刊》2013,36(5):647-657
Abstract There are four passing bands in an infinite truss beam. For an incident bending wave from any branch of a cross‐type structure encountering the conjunction of these four branches of this structure, the induced wave modes in each branch can be predicted by using their dispersion of passing bands. The energy carried by this incident bending wave will be redistributed into these branches by the induced wave modes. The total energy value is conservative. Enlarging the cross‐sectional area or stiffening the material of horizontal members of all dissimilar cells around the outlets of this conjunction substructure enhances the power reduction in the two branches perpendicular to the incident direction. On the other hand, the induced power flow in the branch whose direction is the same as the incident direction can be reduced by stiffening the cross‐sectional area or stiffening the material of diagonal members of these three cells. 相似文献
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Investigating the benefits of using circular die springs instead of rectangular die springs
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D. Gonen A. Oral M. C. Cakir 《Fatigue & Fracture of Engineering Materials & Structures》2015,38(7):799-812
Die springs with rectangular cross section (rectangular die springs) are common in the industry. However, the production of rectangular die springs is difficult, and the cost of production is high. In this study, we examined the use of die springs with circular cross section (circular die springs), which are both easier to produce and less costly, in place of rectangular ones. To this aim, the fatigue life values of both die spring with equivalent specifications were compared experimentally. The results obtained were transferred to the finite element methods software to run the simulation of the fatigue test. From the experimental results obtained, it has been observed that using circular die springs in place of rectangular die springs is always possible, provided that the springs are guided with cast polyamide guides. 相似文献
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Stochastic seismic analysis of long-span bridges with Carbon fibre reinforced polymer (CFRP) cables are presented in this
study through combination of the advantages of the perturbation based stochastic finite element method (SFEM) and Monte Carlo
simulation (MCS) method. Jindo cable-stayed and Fatih Sultan Mehmet (Second Bosporus) suspension bridges are chosen as an
example. Carbon fibre reinforced polymer cable (CFRP) and steel cables are used separately, in which the cable’s cross sectional
area is determined by the principle equivalent axial stiffness. Geometric nonlinear effects are considered in the analysis.
Uncertainties in the material are taken into account and Kocaeli earthquake in 1999 is chosen as a ground motion. The efficiency
and accuracy of the proposed algorithm are validated by comparing with results of MCS method. It can be stated that using
of CFRP cables in long-span bridges subjected to earthquake forces is feasible. 相似文献
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The behavior of stochastically heterogeneous beams, composed of isotropic sub-elements of randomly distributed stiffness is studied. Cross sectional as well as longitudinal heterogeneity are included. Average displacements, reaction forces and their statistical variance are found analytically by a functional perturbation method. Ratio of sub-element to beam characteristic size is not negligible and the use of an equivalent homogeneous structure with the classical effective material properties is not sufficient. The major aim is to study the relation between various microstructure properties (grain size, shape, modulus, statistical correlation lengths etc.) and the overall behavior of linear elastic Bernoulli beams. For the statically determinate case, only cross sectional 2D microstructure statistics is found to affect the elastic response, so that an equal average displacement can be achieved by an equivalent, non-isotropic homogeneous beam. For the indeterminate case, the average values of macro properties are affected by the 3D morphological features. Therefore, the proper equivalent homogeneous beam has to include non-local elastic properties. A simple reciprocal relation, connecting two separate loading systems is found, relating their external forces and displacement statistical variances. Morphological parameters, like two point probability moments, used in the final results are derived analytically, and their physical interpretations are discussed. 相似文献