一种实用的机械结构优化设计方法

提出一种实用的机械结构优化设计方法-ANSYS与导重准则结合法，该方法既能利用结构分析商用软件ANSYS有限元建模，分析求解与结果输出方便的优势，又能发挥结构优化理性准则法。导重法优化效果好，收敛快的优越性，一般只需约5～7次优化迭代计算，即可得到十分重要的优化效果。大大提高了设计效率坦与设计质量。其优越性与实用性在某双模轮胎硫化机的优化设计实践中得到充分验证。     

以ANSYS为分析器以导重法优化器的结构优化设计通用软件开发

研制出以ANSYS为分析器以导重法为优化器的结构自动优化软件SOGAl.该结构优化软件实现了ANSYS与导重法数据的自动交换,克服了优化迭代中的人为因素带来的影响,实现了完全自动化,进一步提高了结构优化导重法的工程实用性.通过对多个工程结构进行优化的应用算例,验证了该软件的可行性与优越性.     

基于导重法的工程结构自动优化通用软件研发

提出衡量结构最优程度的结构最优化指标,利用该指标实现了求解结构最优准则方程组时步长因子的自动选取,研制出以ANSYS为分析器、以导重法为优化器的结构自动优化软件SOGA1.该结构优化软件实现了ANSYS与导重法数据的自动交换,克服了优化迭代中人为因素带来的影响,实现了完全自动化,进一步提高了结构优化导重法的工程实用性.通过对多个工程结构进行优化的应用算例,验证了该软件的可行性与优越性.     

摩天轮结构有限元分析与优化设计

利用ANSYS软件对直径105 m、高120 m摩天轮进行了空载重力工况、偏载重力工况、满载重力工况、普通风载荷工况、冰雪载荷工况、50年一遇风载荷工况和地震载荷工况7种主要工况下的结构有限元分析。取构件的19个主要构件截面尺寸作为设计变量,以摩天轮结构总重量为目标函数,以材料许用应力为约束条件,用导重法对摩天轮结构进行了优化设计。优化设计后,摩天轮不含轿厢的结构重量从689.41吨下降到383.48吨,降重44.4%,各工况下安全系数均达到设计要求,实现了摩天轮结构的轻量化设计,验证了导重法应用于结构优化设计的优越性。     

导重法求解单工况的拓扑优化问题

在拓扑优化中,因为设计变量多并且目标函数和约束函数都是设计变量的隐函数,求解难度较大,所以寻找更快更好的求解方法一直都是拓扑优化问题的研究重点。为此,将导重法引入到拓扑优化的求解中,介绍质量约束下求结构最优性能问题和性能约束下求结构最小质量问题的导重法迭代准则,采用密度惩罚(Solid isotropic material with penalization,SIMP)方法建立单工况下求最小柔度和最小质量这两类拓扑优化问题的优化模型,推导出用导重法求解这两类问题的迭代公式并计算了相应的算例,与ANSYS中采用的优化准则法(Optimality criteria,OC)和序列凸规划法(Sequential convex programming,SCP)进行对比分析。通过计算和对比分析显示出用导重法求解拓扑优化问题具有迭代公式简单、适用范围广、收敛速度快、求解效果好的优点。导重法为拓扑优化问题的求解提供了一条新的途径。     

公路绿篱修剪机结构有限元分析与优化设计

利用ANSYS软件对公路绿篱修剪机进行结构有限元分析,得到了典型工况的应力分布。然后利用结构优化导重法进行以提高结构强度和减轻自重为目标的优化设计。优化后使修剪机结构重量由原来的520.55 kg下降到392.36 kg,降重24.63%;结构最大应力由原来的221.07 MPa下降到142.443 MPa,最大应力下降77.627 MPa,收到了明显优化效果。     

双模轮胎硫化机结构的优化设计

我们在双模轮胎硫化机结构的优化设计中,提出了一种ANSYS与导重准则相结合的优化方法。该方法收敛快,一般只需约5至7次优化迭代计算即可得到十分显著的优化效果,大大提高了优化效率与设计质量。     

某型垃圾中转站压缩机结构分析及优化设计

针对压缩垃圾反作用力载荷的不确定性,垃圾中转站压缩机结构分析与优化设计具有较大难度的问题,在对某垃圾中转站压缩机进行结构有限元分析的基础上,使用ANSYS与导重法相结合的优化方法,成功地对该压缩机进行了以提高结构强度、减少结构重量为目的的优化设计。     

垃圾中转站水平压缩机结构分析及优化设计

利用ANSYS软件对垃圾中转站水平压缩机进行了结构有限元分析,得到了各种工况的应力分布,并利用导重法,对其进行了以提高结构强度、减小结构自重为目的的优化设计,优化后不但结构最大应力从327 MPa减少到170MPa,而且整机自重减少了24%,收到了显著的优化效果。     

探析双模轮胎硫化机结构的优化设计

针对双轮模轮胎硫化机结构设计进行分析,并对结构优化设计进行介绍。探讨了ANSYS和导重准则结合优化法,内容包括:导重法优化,使用ANSYS求结构相应的差分敏度。最后总结了优化迭代历程,内容包括:横梁最小化挠度优化设计,横梁最小化结构重量优化设计,底座优化设计。希望通过对这些内容的分析,能够为双模轮胎硫化机结构的优化设计提供一定帮助。     

一种考虑参数相关性的可靠性优化设计方法

在求解具有非线性相关性结构的可靠性设计优化问题时,现有的相关性处理方法在某些情况下可能会得到精度较低的优化结果。基于Copula函数提出了一种可靠性优化设计方法,用于求解存在非线性相关性结构的可靠性优化设计问题。该方法根据已知的样本对各备选Copula函数进行参数估计,并根据AIC准则选出最优Copula函数。根据最优Copula函数,构建联合概率分布函数,最后求解结构可靠性优化设计问题。通过两个数值算例验证了该方法的有效性,并讨论了不同Copula函数对优化结果的影响。     

An efficient approach for shape optimization of components

The optimization problem of finding the optimal shape of a mechanical component is investigated with the aim of presenting a simple and efficient numerical approach for minimizing stress concentration factor. The proposed approach is based on finite element method in conjunction with the widely used fully stressed design criterion (or the axiom of uniform stress), i.e. for structural shape optimization, an essential requirement for optimality is the achievement of constant tangential stresses along a section of the boundary to be optimized. The design boundary is modeled by using cubic splines, which are determined by a number of control points. The optimal shape of the design boundary with constant stress is achieved iteratively by adjusting the design boundary shape based on a simple logic and algorithm. The result quality in terms of accuracy and efficiency are tested and discussed with finite element analysis examples. The approach presented has the attractive properties that it can be very simply implanted into standard finite element codes.     

基于KNN方法的多约束下连续体结构拓扑优化设计

提出了多约束下连续体结构拓扑优化设计的K邻近(KNN)方法。首先以结构单元作为样本,将整个设计区域看作是样本空间,将连续体结构拓扑优化看作是一种对单元的模式识别;然后利用单元应力和位移灵敏度作为单元样本的特征向量,利用特征向量的欧氏距离为识别标准,引入模式识别的KNN方法进行多约束下的连续体结构拓扑优化设计;最后给出计算示例的优化结果来表明该方法是可行的。     

Evolutionary forging preform design optimization using strain-based criterion

Preform design plays an important role in forging design especially for parts with complex shapes. In this paper, an attempt was made to develop a topological optimization approach for the preform design in bulk metal forming processes based on the bidirectional evolutionary structural optimization strategy. In this approach, a new strain-based element addition and removal criterion has been proposed for evaluating and optimizing the material flow in the forging process. To obtain a smooth preform boundary, a closed B-spline curve based on the least square algorithm is employed to approximate the uneven surface of the updated preform profile. A C# program has been developed to integrate the FE simulation, shape optimization, and surface approximation processes. Two 2D forging preform design problems are evaluated by using the developed method. The results suggest that the optimized preform with the strain uniformity criterion has shown better performance in improving the material flow and deformation uniformity during the forging process. The results also demonstrate the robustness and efficiency of the developed preform optimization method.     

超微型车车身新结构的开发

介绍了超微型电动车车身结构特点,提出了超微型车的结构设计准则.在此基础上以拓扑优化的结果为依据,开发了一种新型的车身结构,并进行了车身结构的优化设计.最后经有限元方法验证了这种新结构是安全、可行的,并且更轻量化.     

基于连续响应表面法的汽车结构耐撞性仿真优化

汽车结构的耐撞性及碰撞吸能优化是现代汽车工业重要的研究内容.耐撞性的优化涉及到材料与结构的众多参数,传统的设计、仿真及碰撞试验往往只能在一定程度上改善结构的碰撞性能,而无法达到限定条件下的最优状态.为解决汽车碰撞的优化问题,文中采用连续响应表面方法,通过变量筛选技术和一阶线性响应表面模型,并结合非线性有限元程序进行全局寻优.汽车前端结构的耐撞性优化表明,该方法具有较高的精度和稳定性.     

Materials selection for environmentally conscious design via a proposed life cycle environmental performance index

Although product design methods are well developed, the recent rise of environmentally conscious design, which includes materials selection as a key element, mandates the development of new engineering tools for decision-making. In this investigation, a method for establishing a life cycle environmental performance index is developed; it is envisioned that the index can be integrated into an environmentally conscious design process. The method addresses such traditional design factors as structural constraints and incorporates an additional consideration, the life cycle environmental impact. The method is applied to the design of an air conditioner support plate. In this application, it is desired to select a material that provides minimal environmental impact, subject to stiffness and strength constraints. Pareto optimization is adopted to analyze the results. The case study shows that the decision-making analysis can provide design guidelines and a criterion for materials selection to achieve environmentally conscious design.     

结合专家群体评估法的渐进结构优化算法

结构拓扑优化作为现在迅速发展的结构化设计的一个分支,已得到广泛应用。基于渐进结构优化(ESO)方法,结合灰色理论中的专家群体评估法,得到一种新的处理多目标优化的方法。首先使用线性加权法对一平面简支梁进行优化分析得到三组拓扑结构。然后运用该新方法对同一算例进行优化得到三组拓扑结构。并将最终拓扑结构进行对比。     

An enhanced optimization approach based on Gaussian process surrogate model for process control in injection molding

A stepwise optimization approach based on Gaussian process (GP) surrogate model is proposed to determine the process parameters and improve the quality control for injection molding. In order to improve the global performance in this optimization, an enhanced probability of improvement criterion is also introduced. Firstly, GP surrogate model is constructed with the initial samples which are obtained from an optimal design of experiment method. GP is capable of giving both a prediction and an estimate of the confidence for the prediction simultaneously. Secondly, an enhanced probability of improvement criterion is used to find the direction of adding training samples and optimize the surrogate model. Since the global optimal region of the model become accurate efficiently after steps of optimizing the surrogate model, the proposed enhanced probability of improvement criterion can switch more swiftly to global optima compared with other improvement criterion. Finally, an auto front grille molding process is taken as an example to illustrate the method. The results show that the proposed optimization method can effectively decrease the warpage of injection-molded parts.     

基于可靠性分析及频率约束的结构优化

对基于结构可靠性分析的结构优化作了简短评述。在此基础上，引入结构动特性的主要指标之一的结构固有频率，提出了一种新的结构优化形式。这种形式实质上是将可靠性优化与动力学优化有机地结合起来。本文算例表明，这种方法是可行的。