面向动力学性能的薄壁加筋板结构阻尼与筋条布局协同优化设计

为减小薄壁加筋结构在动态环境下的振动,提出了加筋肋布局和阻尼层拓扑一体化设计方法。以含表层阻尼材料的薄壁加筋板结构为研究对象,结合阻尼材料惩罚模型与基结构优化方法,引入筋条密度和阻尼单元密度两类独立设计变量,考虑筋条和阻尼材料的体积约束,建立最小化动态柔度的阻尼材料拓扑和筋条布局的协同优化模型,实现面向动态响应最小化的含阻尼层的薄壁加筋结构最优设计。通过不同阻尼、不同频率下的含表面阻尼层加筋板的多个数值算例,验证了所提方法和模型的有效性。     

高速机床工作台筋板的结构仿生设计

针对高速机床工作台的轻量化设计要求,采用结构仿生的方法对其筋板布置方式和参数进行了优化。在分析轻质高效生物体结构的主要特点及其构型规律的基础上,总结出几条轻量化仿生设计准则,并根据结构仿生的基本方法提出工作台筋板的6种仿生构型。利用Ansys的APDL程序分别确定最优参数,验证轻量化效果。结果表明:根据变形区域调整筋板分布形式,以及在最大变形梯度方向上设置对角筋能够实现结构比刚度效能的提高,为改变传统的筋板设计思路提供了一种新方法。     

薄板结构的加强筋自适应成长设计法

在对自然界分枝系统形态的最优性及其成长机理的研究基础上,以薄板结构的加强筋分布设计为例,提出了一种自适应成长设计法。在给定的载荷及支撑条件下,薄板结构的加强筋从事先选定的一些“种子”出发,在有限元分析的基础上,遵循自适应成长规律,沿着能使结构整体刚度最大的方向成长。对一些典型的薄板结构进行了设计,设计结果表明所提出的方法比现有的设计方法简单而高效。     

轻型货车EQ1060F车身的结构优化设计研究

主要研究轻型货车 EQ1 0 6 0 F驾驶室车身结构优化设计中的一些关键问题 ,包括结构有限元分析、优化方法选择、敏度分析和结构重分析 ,选择了序列二次规划法用于结构优化问题且收敛效果较好。该研究为汽车车身设计提供了一条新的设计思路。     

轻型货车EQl060F车身的结构优化设计研究

主要研究轻型货车EQl060F驾驶室车身结构优化设计中的一些关键问题,包括结构有限元分析、优化方法选择、敏度分析和结构重分析,选择了序列二次规划法用于结构优化问题且收敛效果较好。该研究为汽车车身设计提供了一条新的设计思路。     

基于动力学特征的π型龙门框架的结构优化

通过应用有限元模态分析理论,对π型龙门框架存在的动力学问题进行了研究。根据实际情况,设计了2种不同的内部筋板,经过ANSYS Workbench软件的结果对比,得出了不同的筋板对π型龙门框架的动力学特性具有显著的影响的结论,为π型龙门框架的结构优化设计提供了一定的理论依据。     

考虑连接性的三明治阻尼复合结构拓扑优化设计

三明治阻尼复合结构的力学性能取决于阻尼层材料的性能,综合考虑该结构的阻尼性能和可制造性要求,提出了一种面向结构宏观性能并考虑连接性的三明治阻尼复合结构拓扑优化设计方法。以最大化结构模态阻尼比为目标,考虑微结构刚度相材料的连接性,通过组合强制性连接约束法和非线性扩散法,构建了连接性约束下的阻尼复合材料微结构的优化设计模型,并结合3D打印技术实现了三明治阻尼复合结构的制造。运用所提方法对典型结构进行优化设计,得到了刚度相保持连接的阻尼复合结构,且优化后的结构阻尼变大,结构的频率响应变小,实现了三明治阻尼复合结构材料结构设计制造协同优化设计。仿真和实验结果表明,在微结构上存在最优的阻尼材料体积分数使优化后的三明治结构频率响应最小。     

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.     

Optimum design of composite laminated plates via a multi-objective function

This paper deals with the optimum design of composite laminated plates under stiffness and gauge constraints. A multi-objective function which combines the plate weight and the strain energy stored in the plate by weighting parameters is introduced. This objective function is minimized while satisfying constraints such as the structural deformation and the limits on design variables. Both ply orientation angles and ply thicknesses of the composite plate are used as the design variables. The stiffness analysis is performed by the finite element method in which a triangular element is used that is suitable for the analysis of thin to thick plates and includes the transverse shear effects. Analyses of the derivatives of the objective function and the constraint functions with respect to the design variables is performed analytically. The mathematical programming method called the constrained variable metric is used to solve this optimum problem. An example is provided for the optimal design of a rectangular laminated plate.     

基于拓扑优化的卧式旋压机床身加强肋布局优化设计方法

提出了基于拓扑优化的卧式旋压机床身加强肋布局优化设计方法。在确定设计空间及载荷后,采用带惩罚的变密度法(Solid Isotropic Microstructures with Penalization,SIMP)的结构拓扑优化技术,以多工况静力结构柔度和1阶自然频率为优化目标,建立了床身模结构拓扑优化模型,并在考虑工艺性的前提下,确定了床身板件焊接加强肋的最优布局。优化前、后的对比表明,优化后床身的静、动态性能均得到了显著提高,最大应力下降了13.39%,导轨刚度提高10.78%,1阶自然频率提高了9.28%。     

含离散源损伤Z向增强复合材料加筋板压缩特性研究

以含穿透中央筋条的切口模拟离散源损伤,对无增强、Z-pin增强、改进锁式缝合增强、Tufting缝合增强复合材料加筋板进行轴向压缩试验,研究含离散源损伤Z向增强加筋板的损伤扩展模式与破坏特征。结果表明,壁板和筋条间的Z向增强有效控制了壁板与筋条的脱粘,提高了加筋板的屈曲载荷。切口前端的分层只引起局部的屈曲,沿切口方向未切断筋条的断裂和壁板边缘的突然压溃导致加筋板的最终破坏。三维有限元渐进损伤分析结果显示,选用Hashin判据作为失效判据,可以很好地模拟含离散源损伤复合材料加筋板的轴向压缩渐进损伤过程。采用线约束模拟壁板与筋条翼缘之间的Z向增强是合理的,线约束的引入在损伤扩展至筋条下方壁板区域后有效控制了损伤的扩展。     

基于MSC.Patran/Nastran的桥式起重机主梁优化设计

针对现行主梁设计中存在的结构笨重、材料浪费严重的问题,基于MSC.Patran平台,构造某型桥式起重机箱型主梁模型,应用MSC.Nastran对其进行结构和受力分析;以主梁各板厚度为优化变量,以强度和刚度指标为约束,应用MSC.Nastran提供的优化方法,进行以主梁结构轻量化为目标的优化计算,得到合理的优化结果。对我国桥式起重机的现行设计方法进行了一些改进和探索。     

基于ANSYS吊车支撑梁的分析设计及优化研究

本文根据某企业厂房的需求,按照常规设计方法完成了5 t吊车支撑梁的结构设计;采用ANSYS中APDL方式,建立了支撑梁结构的有限元分析模型,探讨了不同约束方式对支撑梁分析结果的影响,然后提出了以用材最省为优化目标的结构形状优化模型,采用子问题优化方法完成了优化迭代,得到的结果显示优化结果不仅能够满足其强度和刚度要求,而且使其用材达到最省,本文所开展的研究对同类产品的结构设计具有指导意义。     

Analysis of reinforced or cellular panels and decks

A popular and efficient design for lightweight structural decks, floors, roofs and wall panels consists of a flat plate reinforced by and composite with one or two sets of ribs. A variation of the reinforced plate is the so-called cellular construction comprised of two membranes connected to ribs to from a discrete core sandwich structure. Until recently, no rational methods were available for the stress and deflection analysis of these structures. This paper presents formulas for the exact elastic analysis of late- tringer- iaphragm decks (composite stringers and non-composite diaphrams) and waffle decks (stringers and diaphrams both composite) which are rectangular with simple end and flexible side supports. Cellular construction is dealt with by creating a condition of anti-symmetry with respect to the middle plane. The formulas are derived by finding closed form solutions to the summation equation mathematical models which were written by use of a macro discrete field approach. The formulas are numerically illustrated through use of a simple programmable pocket calculator which is judged suitable for design office use and optimization studies. The examples permit comparisons between the single plate and cellular P-S-D panels and waffle plates.     

基于边缘纤维屈服准则的薄板结构加强筋的优化设计法

提出一种基于边缘纤维屈服准则的薄板结构加强筋的优化设计法,在给定荷载及支撑的条件下,用壳单元模拟薄板壳,用梁单元模拟加强筋,并根据梁的边缘纤维屈服准则给出加强筋截面高度的修改公式,通过结构重分析不断修改梁单元的尺寸,使每个梁单元的边缘纤维达到屈服,满足迭代收敛准则后删除截面高度小于阈值的梁单元,获得薄板结构加强筋的新的分布形式并提高阈值.在加强筋的新的分布形式基础上进行下一轮优化设计.当阈值达到阈值上限时优化设计结束,从而获得最终的加强筋的分布形式及其截面尺寸.算例表明该方法简单有效,计算量小.     

基于有限元方法的支承法兰盘结构优化研究

重载变速箱支承法兰盘的结构设计对节约成本、减小箱体整体重量有着重要的影响。基于支承法兰盘的结构特征,通过目标函数的建立、设计变量的选取以及约束条件的确定建立了优化设计的有限元模型,并对法兰盘进行了静力分析。在结构轻量化的目标下,通过对法兰盘进行优化分析,得到了法兰盘安全、可靠的结构最优尺寸,减少了材料的使用。对优化后的模型进行了安全校核,验证其完全满足设计要求。该分析方法对法兰盘结构尺寸的优化具有一定的参考作用。     

Light-Weight Design Method for Force-Performance-Structure of Complex Structural Part Based Co-operative Optimization

A light?weight design method of integrated structural topology and size co?optimization for the force?performance?structure of complex structural parts is presented in this paper. Firstly, the supporting function of a complex structural part is built to map the force transmission, where the force exerted areas and constraints are considered as connecting structure and the structural configuration, to determine the part performance as well as the force routines. Then the connecting structure design model, aiming to optimize the static and dynamic performances on connection configuration, is developed, and the optimum design of the characteristic parameters is carried out by means of the collaborative optimization method, namely, the integrated structural topology optimization and size optimization. In this design model, the objective is to maximize the connecting stiffness. Based on the relationship between the force and the structural configuration of a part, the optimal force transmission routine that can meet the performance requirements is obtained using the structural topology optimization technology. Accordingly, the light?weight design of conceptual configuration for complex parts under multi?objective and multi?condition can be realized. Finally, based on the proposed collaborative optimization design method, the optimal performance and optimal structure of the complex parts with light weight are realized, and the reasonable structural unit configuration and size charac?teristic parameters are obtained. A bed structure of gantry?type machining center is designed by using the proposed light?weight structure design method in this paper, as an illustrative example. The bed after the design optimization is lighter 8% than original one, and the rail deformation is reduced by 5%. Moreover, the lightweight design of the bed is achieved with enhanced performance to show the effectiveness of the proposed method.     

薄壁覆盖件的结构优化设计

研究了薄壁覆盖件结构优化设计中的一些关键技术，包括薄壁覆盖件的结构有限分析、优化方法选择、敏度结构重分析，选择了序列二次规划法用于结构优化问题，睡敛效果较好 。以汽车车身为例，对其进行了结构优化设计，计算结果适用，所编制的软件（ＯＰＴＳＨＥＥＴ）使用方便可靠。     

Conditions of rib design for polycarbonate resin with high glossy surfaces

Much attention has been being given to the importance of product surfaces in the field of plastic parts, as industrial design has become one of the key elements of product success. These plastic parts incorporate rib-like geometries on the non-appearance surfaces of plastic in order to increase the stiffness of rigidity of the section, but they often cause appearance problems of the product’s surface overall by making a sink mark on that surface. The thickness, height and draft-angle of the rib are generally known as major parameters influencing the sink mark on the appearance surface. Therefore, designers of plastic parts must determine the variables of reinforcing ribs. The goal of this study is to find the optimum design variables in the mixing conditions of the thickness, the height and the draft angle of reinforcing ribs so that designers of plastic parts can easily determine the conditions of the reinforcing ribs as the part’s section thickness varies within an objective limit in polycarbonate plastic resin and a high glossy surface that are widely applied in the creation of plastic products. We investigated the actual depths of sink marks on the surface of a specimen that was manufactured with an injection mold specifically for this study. Response surface methodology with the Box-Behnken design was used to analyze the regression curve of real depths with combinations of the thickness, height and draft angle of the ribs. The result shows that the most influential factor to increase the shrinkage is the thickness of ribs and that the optimum value of the rib thickness is a range from multiple of 0.25 to 0.34 of the section thickness. Also, the rib height and rib draft angle are not major factors that can change the sink amount.     

基于Matlab的工艺参数优化设计方法研究

以车削加工工艺参数为例,根据设计要求与特点,建立车削加工工艺参数优化设计,在保证零件的各项加工要求下,使单件加工刀具成本最小,加工时间最少.并应用Matlab软件对其进行了优化设计,并与其它优化方法求解结果进行了比较.结果表明:采用Matlab软件进行优化设计可获得最优解,从而缩短了设计周期,降低了刀具成本、提高了加工效率.