基于疲劳寿命分析的结构拓扑优化设计方法及应用研究

发布时间：2018-03-24 20:58

本文选题：拓扑优化　切入点：有限元　出处：《浙江大学》2017年硕士论文

【摘要】：渐进结构优化(ESO)方法是拓扑优化方法中的一个重要分支,双向渐进结构优化(BESO)方法在其基础上,解决了单元误删除,结构棋盘状分布以及网格依赖性等问题。现存的渐进结构优化方法主要是基于应力分析的,但由于工程应用中疲劳破坏引起的结构断裂对安全生产和工程机械的使用寿命产生的巨大影响,因此在设计重型机械的核心部件时将疲劳寿命分析作为一个参考因素就显得尤为重要。本文的第一部分根据单轴疲劳寿命估算方法得到结构中各单元的疲劳寿命,然后根据疲劳寿命的大小移除那些寿命值相对较高的单元。考虑到单元误删除、棋盘状分布和网格依赖性的影响引入过滤机制,并对过滤网格进行改进,考虑到各方向寿命变化的梯度影响将过滤网分为四个部分并进行相应的优化计算。第二部分通过研究分析现有的MATLAB结构优化法,开发出全新的MATLAB与ABAQUS结合的结构优化的系统。将ABAQUS作为有限元计算和建模的前处理器,根据其计算得出的各单元应力分布情况使用MATLAB编写疲劳寿命计算和拓扑优化计算的相关程序。第三部分结合工程应用的实际需求,引入多轴疲劳分析的概念。使用Wang-Brown多轴载荷循环计数法对非比例变幅载荷的加载进行循环计数,随后使用一种基于降维思想的多轴疲劳损伤模型对单元的疲劳寿命进行估算,紧接着采用线性损伤累积准则对各载荷循环的疲劳损伤进行累积。最终根据多轴疲劳分析得到的疲劳寿命进行三维结构的拓扑优化设计。并以推耙机中的H型架横梁模型为工程实例进行拓扑优化,解决了推耙机H型架横梁在实际工作中损耗过于严重的问题,在使用同样体积的材料情况下大幅提高了结构件的使用寿命。
[Abstract]:Evolutionary structural optimization (ESO) method is an important branch of topology optimization method, bi directional evolutionary structural optimization (BESO) method on the basis of solving the unit accidentally deleted, on issues such as checkerboard and mesh structure distribution. The evolutionary structural optimization method based on stress analysis of the main if existing, but because the great influence of fatigue engineering structural damage fracture caused for the production safety and the service life of engineering machinery, so in the design with the core component of heavy machinery when the fatigue life analysis as a reference factor is particularly important. The first part of this paper according to the uniaxial fatigue life estimation method of the fatigue life obtained in each unit structure then, according to the fatigue life of the size of the removal of those values of life relatively high unit. Taking into account the unit accidentally deleted, checkerboard and mesh dependence distribution effects of lead The filtering mechanism, and the filtering mesh was improved, taking into account the effect of changes in the direction of the gradient of life and the filter screen is divided into four parts and the corresponding optimization calculation. The second part through the analysis of the existing MATLAB structure optimization method, system structure optimization of MATLAB and ABAQUS combined with new ABAQUS as. Finite element calculation and modeling of the pre processor, the unit according to the calculated stress distribution of MATLAB prepared using fatigue life calculation and topology optimization calculation procedures. In the third part, combined with the engineering application of the actual demand, the introduction of the concept of analysis of multiaxial fatigue loading. Using Wang-Brown multiaxial cycle counting method of non proportional cyclic loading cycle count, then use a multiaxial fatigue damage model based on dimension reduction method to estimate the fatigue life of the unit, followed by The linear cumulative damage criterion on the fatigue damage of the loading cycle of accumulation. Finally according to the multiaxial fatigue fatigue life analysis of the topology optimization design of 3D structure. Taking H push the rake machine in frame beam model as an example of topology optimization, solve the pushing and rake machine H frame beam in practical work the loss is too serious problems in the use of materials of the same size greatly improve the service life of the structure.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB12

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