基于有限元方法的圆筒接管壁厚设计

结合我国压力容器分析设计标准JB4732-1995,采用有限元方法(FEM)对圆筒形容器的开孔应力集中及满足强度要求的接管最小壁厚进行分析。分析结果表明,开孔造成的应力集中系数处在3~10之间,并随着开孔直径d和简体内径D的增加而增加;通过采用不同路径分析得到的结果进行对比发现,传统的分析路径偏于保守,标准GB150-2011推荐的应力评定路径分析结果更接近生产实践,有限元分析方法可以方便、可靠地用于圆筒形容器的开孔设计。     

不确定性桁架结构区间有限元分析的区间因子法

利用区间因子表征区间变量的不确定性,将区间变量表示为其均值和区间因子的乘积;根据区间运算规则,将区间分析与有限元方法相结合,提出了非概率不确定的结构的一种区间有限元分析的方法。构建了区间参数杆系结构在区间荷载作用下的分析模型,导出了结构的区间位移和区间应力响应区间变量表达式。通过算例考察了任一结构参数和荷栽的不确定性对位移和应力的影响,获得了一些有意义的结论。     

基于塑性极限分析的球壳开孔接管整体补强设计方法

在塑性极限分析的基础上，本文提出受内压球壳开孔接管的一种整体补强设计方法。该方法不仅适用于三种整体补强形式：平齐接管补强，内伸接管补强以及密集补强，而且适用于大开孔情况（ｒ／Ｒ≤０．８）。与ＰＶＲＣ及ＡＤ规范的比较证明本方法是合理和可靠的。     

复合中心钻护锥孔锥角的合理选用

复合中心钻护锥孔锥角的合理选用兰州量具刃具厂（７３０００）马鸿源郗同盔国标规定中心钻护锥孔锥角为１２０°。护锥孔的作用是保护６０°定位锥孔,使它不受外界碰伤。通过试验,发现选用９０°护锥角比选用１２０°更加合理。１．定位锥孔不易被碰伤现以４ｍｍ复合...     

压力容器开孔接管区的有限元分析和实验研究

根据对压力容器正交和切向开孔接管区进行的有限元分析,获得容器筒体、接管及其连接部位的应力分布结果,利用电阻应变测试技术进行现场测试。结果表明,压力容器开孔接管产生明显的应力集中,各类应力的最大值发生在接管与筒体连接处,是筒体失效的危险区域;与压力容器正交开孔接管相比,压力容器切向开孔接管的应力分布更趋复杂,有更明显的应力集中。     

基于区间数的数控机床综合性能评价

数控机床是装备制造业的关键装备,数控机床性能评价是数控机床设计、选型和改进改型的重要依据。针对现有数控机床性能评价研究存在的不足,提出了一种新的基于区间数的数控机床综合性能评价方法,建立了数控机床综合性能评价指标体系。利用区间层次分析法确定了数控机床综合性能评价指标的区间数权重,进一步建立了基于区间数的数控机床综合性能评价模型。应用实例的计算结果表明,所建立的数控机床综合性能评价模型合理有效。     

基于区间层次分析法的机械加工工艺方案评价研究

机械加工工艺方案评价是选择和优化加工工艺的关键措施。针对机械加工工艺方案评价过程中存在的不确定性,提出了一种新的基于区间层次分析法的机械加工工艺方案评价方法。首先建立了多层次的机械加工工艺方案评价指标体系,然后利用区间层次分析法确定了机械加工工艺方案评价指标的区间数权重。在此基础上,结合区间数理论建立了基于区间层次分析法的机械加工工艺方案评价模型。最后对某万向节活动叉的3套工艺方案进行了评价,验证了该方法的合理性和有效性。     

基于区间数的生产供应网络弹性评价

近几年包括自然灾害、人为事故以及社会事件在内的突发事件频发,对本就极具复杂、脆弱的供应网络造成极大的破坏。因此,急需构建弹性供应体系,设计能够承受破坏性事件并从中迅速恢复的供应网络。选取多个因素综合评价供应的弹性强度,并用区间数量化各因素以测定其不确定性信息。利用IAHP法确定各因素决策权重,结合TOPSIS-GRA法衡量各供应商弹性供应能力。最终通过实例分析,验证该评价决策方法的可靠性和实用性。     

基于区间方法的反射面天线变形分析

针对地基天线反射面的非概率不确定性变形问题进行了分析。运用区间矩阵摄动法计算得到天线结构静力学的响应区间。针对复杂区间运算引起的区间扩张问题,通过分析区间参数的相对不确定量,确定了适用于多变量、复杂结构的区间运算的区间截断因子取值准则。结合区间矩阵摄动法和新的区间截断方法计算得到较为精确的天线反射面变形区间。将本文方法应用于六杆桁架结构及复杂的反射面天线结构,并将结果与蒙特卡罗方法得到的结果作了比较,从而验证了本文方法的可行性和有效性。     

Process optimal design in non-steady forming of porous metals by the finite element method

A new approach to process optimal design in non-steady forming of porous metals is presented. In this approach, the optimal design problem involving diverse objective functions and design variables is formulated on the basis of the finite element process model, and a derivative-based approach is adopted as the solution technique. The process model, the formulation for process optimal design, the schemes for the evaluation of the design sensitivity, and an iterative procedure for optimization are described in detail. The validity of the schemes for the evaluation of the design sensitivity is examined by performing a series of numerical tests. The capability of the proposed approach is demonstrated through application to a selected design problem.     

结合有限元法的空间相机优化设计

优化设计是改进设计的有效方法,有限元法是解决分析问题的有力工具.简要阐述了空间光学仪器结合有限元法的优化设计方法,并以某空间相机为例详细介绍了系统的结构优化过程,验证了其优化后的性能.     

Combined finite volume and finite element method for convection-diffusion-reaction equation

A combined finite volume and finite element method is presented for solving the unsteady scalar convection-diffusion-reaction equation in two dimensions. The finite volume method is used to discretize the convection-diffusion-reaction equation. The higher-order reconstruction of unknown quantities at the cell faces is determined by Taylor’s series expansion. To arrive at an explicit scheme, the temporal derivative term is estimated by employing the idea of local expansion of unknown along the characteristics. The concept of the finite element technique is applied to determine the gradient quantities at the cell faces. Robustness and accuracy of the method are evaluated by using available analytical and numerical solutions of the two-dimensional pure-convection, convection-diffusion and convection-diffusion-reaction problems. Numerical test cases have shown that the method does not require any artificial diffusion to improve the solution stability. This paper was recommended for publication in revised form by Associate Editor Dongshin Shin Pramote Dechaumphai received his B.S. degree in Industrial Engineering from Khon-Kaen University, Thailand, in 1974, M.S. degree in Mechanical Engineering from Youngstown State University, USA in 1977, and Ph.D. in Mechanical Engineering from Old Dominion University, USA in 1982. He is currently a Professor of Mechanical Engineering at Chulalongkorn University, Bangkok, Thailand. His research interests are numerical methods, finite element method for thermal stress and computational fluid dynamics analysis. Sutthisak Phongthanapanich received his B.S. degree in Mechanical Engineering from Chiangmai University, Thailand in 1990. He then received his M.S., and Ph.D. degrees in Mechanical Engineering from Chulalongkorn University, Thailand in 2002, and 2006, respectively. He is a Lecturer of Mechanical Engineering Technology at King Mongkut’s University of Technology North Bangkok, Bangkok, Thailand. His research interests are finite element method, finite volume method, mesh generation and adaptation, and shock wave dynamics.     

Design of interference fits via finite element method

Studies of interference fits in ring gear-wheel connections show that the traditional design method based on thick-wall cylinder theory has some limitations. Application of the finite element method (FEM) for the three-dimensional stress analysis of interference fitted connections gives more complete and accurate results than the traditional method. An improved design method utilizes two safety factors, λ_s and λ_p, providing a new approach for evaluating the quality of interference fits. A tolerancing method utilizing the I_max and I_min curves provides a quantitative guideline for interference fit design. The selective assembly method combined with the FEM-based method for interference fit design provides an effective approach to achieve more reliable interference-fitted connections and more precise assembly with lower manufacturing cost.     

多功能轮椅车设计及其有限元分析

设计了一种新型的、具有移动行驶、下肢康复训练、高端取物等功能的多功能轮椅车.通过建立多功能轮椅车的有限元模型,对轮椅车整体结构强度进行有限元分析,提出了改进措施,从而降低产品开发成本和缩短开发周期.     

车用爪式联轴器的有限元优化设计

利用美国MSC公司提供的CAE软件对常用的联轴器结构的应力分布及变形进行分析。利用Pro/E建模并导入到ANSYS后生成有限元分析模型,利用ANSYS对模型进行计算,得到应力分布,并利用优化方法以减少应力集中为目标对模型进行优化,以期达到结构合理、综合强度加强的目的。     

采用有限元法进行空气弹簧隔振器的辅助设计

由于空气弹簧隔振器的刚度不仅与空气室的空气压力、承载载荷有关,还与不同形式空气室的有效承压面积、胶料性能等有关,因此各种形式的空气弹簧隔振器其刚度特性相差很大.采用实验的方法,设计一种空气弹簧隔振器必将耗费大量的人力物力,而采用经验公式,又存在较大困难.因此采用有限元方法,解决空气弹簧隔振器设计必须考虑的气固耦合、非线性等关键技术,进行空气弹簧隔振器结构的静态应力、变形及隔振系统的振动特性分析,优化空气弹簧隔振器的设计流程,并进行试验验证.     

Gear hot forging process robust design based on finite element method

During the hot forging process, the shaping property and forging quality will fluctuate because of die wear, manufacturing tolerance, dimensional variation caused by temperature and the different friction conditions, etc. In order to control this variation in performance and to optimize the process parameters, a robust design method is proposed in this paper, based on the finite element method for the hot forging process. During the robust design process, the Taguchi method is the basic robust theory. The finite element analysis is incorporated in order to simulate the hot forging process. In addition, in order to calculate the objective function value, an orthogonal design method is selected to arrange experiments and collect sample points. The ANOVA method is employed to analyze the relationships of the design parameters and design objectives and to find the best parameters. Finally, a case study for the gear hot forging process is conducted. With the objective to reduce the forging force and its variation, the robust design mathematical model is established. The optimal design parameters obtained from this study indicate that the forging force has been reduced and its variation has been controlled.     

基于有限元法轴段偏中时轴系校中状态的研究

依据船舶轴系直线校中原理,介绍了ANSYS环境中轴系校中建模的方法和参数的设置,并在ANSYS环境中建立了轴系校中计算的有限元模型.简述了轴系直线校中法,详细说明了轴段偏中时轴系校中的状态,得出了轴段校中时轴承负荷、轴系挠度、轴系转角、轴系剪力等参数,并与轴系偏中时轴承负荷、轴系挠度、轴系转角、轴系剪力等参数做比较,得到了轴系校中参数变化规律,同时计算得出了轴段偏中产生的附加负荷对轴系校中的影响,为船舶轴系校中设计及检修提供了依据.     

自调式离合器膜片弹簧优化设计及有限元分析

自调式膜片弹簧离合器通过一套补偿机构,使离合器在使用过程中自动调节补偿由于摩擦片磨损而引起的工作压紧力变化。针对某型皮卡车的自调式膜片弹簧离合器中的关键元件膜片弹簧进行了优化设计,并利用MATLAB软件对优化数学模型进行设计计算。从膜片弹簧弹性特性曲线优化前后对比得出,当形变量相同时,得出的压紧力明显减少,使离合器操纵轻便舒适,充分展示了优化设计方法的优势。最后利用CATIA软件对膜片弹簧进行了有限元分析,达到了设计目标。