连续体结构拓扑优化的一种新变密度法

从变密度法SIMP和RAMP存在的问题出发,提出一种指数形式的惩罚函数,研究了惩罚系数对拓扑优化的影响,解决了SIMP和RAMP刚度矩阵奇异、惩罚系数太大得不到合理拓扑的问题,得出惩罚系数的取值范围,两个算例分析验证了文中提出方法的正确性和优势,并和SIMP法进行了比较.     

A regularization scheme for explicit level-set XFEM topology optimization

Frontiers of Mechanical Engineering - Regularization of the level-set (LS) field is a critical part of LS-based topology optimization (TO) approaches. Traditionally this is achieved by advancing...     

多工况载荷下连续体结构拓扑优化设计研究

在充分研究多工况下连续体结构拓扑优化的研究现状和理论的基础上,采用密度插值格式和优化准则法,以各工况载荷下的结构刚度最大化为优化目标函数,基于线性加权和法建立多工况下结构拓扑优化设计模型,给出基于敏度过滤技术改进的设计变量更新格式,并提出确定载荷权重的新方法即α-方法.该方法简单、实用,算例证明了其有效性.     

Multi-objective reliability-based topology optimization of structures using a fuzzy set model

This research proposes a multi-objective reliability-based topology optimization (MORBTO) for structural design, which considers uncertain structural parameters based on a fuzzy set model. The new technique is established in the form of multi-objective optimization where the equivalent possibilistic safety index (EPSI) is included as one of the objective functions along with mass, and compliance. This technique can reduce complexity due to a double-loop nest problem used previously due to performing single objective optimization. The present technique can accomplish within one optimization run using a multi-objective approach. Two design examples are used to demonstrate the present technique, which have the objectives as structural mass and compliance with the constraint of structural strength. The results show the proposed technique is effective and simple compared to previous techniques.

     

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Frontiers of Mechanical Engineering - Enabled by advancements in multi-material additive manufacturing, lightweight lattice structures consisting of networks of periodic unit cells have gained...     

A MATLAB code for the material-field series-expansion topology optimization method

Frontiers of Mechanical Engineering - This paper presents a MATLAB implementation of the material-field series-expansion (MFSE) topology optimization method. The MFSE method uses a bounded material...     

ANSYS参数化有限元技术在板壳结构拓扑优化设计中的应用

拓扑优化设计是工程结构降低成本、提高性能的有效手段之一.在ANSYS对加筋板壳结构的有限元分析基础上,可以对板壳结构的加强部件分布进行合理设计.着重介绍了使用ANSYS参数化语言进行加筋板壳结构的分析方法.     

Development of a new concrete pipe molding machine using topology optimization

Sulfur polymer concrete (SPC) is a relatively new material used to replace Portland cement for manufacturing sewer pipes. The objective of this work is to develop an efficient molding machine with an inner rotating die to mix, compress and shape the SPC pipe. First, the alternative concepts were generated based on the TRIZ principles to overcome the drawbacks of existing machines. Then, the concept scoring technique was used to identify the best design in terms of machine structure and product quality. Finally, topology optimization was applied with the support of the density method to reduce mass and to displace the inner die. Results showed that the die volume can be reduced by approximately 9% and the displacement can be decreased by approximately 3% when compared with the initial design. This work is expected to improve the manufacturing efficiency of the concrete pipe molding machine.

     

Manufacturing cost constrained topology optimization for additive manufacturing

Frontiers of Mechanical Engineering - This paper presents a manufacturing cost constrained topology optimization algorithm considering the laser powder bed additive manufacturing process. Topology...     

变速器壳体拓扑优化设计分析

介绍了变速器壳体设计的一般原则,简述了结构拓扑优化设计技术的基本功能,以实际开发项目中的变速器壳体技术设计为例,介绍了变速器设计的基本要求,提供了变速器壳体设计的一些经验数据,并阐述了壳体材料的选择和结构的工艺性.采用有限元分析方法,对变速器壳体进行拓扑优化分析,通过不同的拓扑优化方法,分析了先进设计方法的实现方式,为实现变速器合理优化设计提供了依据.     

一种基于ESO算法的结构拓扑优化方法

ESO和SIMP是两种主流的结构拓扑优化方法,其中后者被广泛地应用在商用有限元软件(例如MSC.Nastran)的拓扑优化模块中.比较了两种算法的基本原理,并且基于ESO算法,选择Matlab和MSC.Nastran作为计算平台,开发了二者的数据接口,从而实践了一种方便易行的拓扑优化方法.通过一个典型薄壁件的算例,将该优化方法和MSC.Nastran得到的结果进行比较,证明该方法优化的结构在等强度条件下比后者轻5.1%,在等质量条件下单元最大应力比后者小13.8%,验证了该方法的可靠性和有效性.     

Manufacturing- and machining-based topology optimization

Topology optimization is used in the initial stage of the product manufacturing process. However, the non-manufacturable or non-machineable results of topology optimization have become an obstacle to process manufacturing. This paper proposes a modified topology optimization method by adding manufacturing and machining constraints to the topology optimization formulation. A hybrid topology optimization algorithm (combining the method of moving asymptotes and wavelets) is applied to solve this optimization problem. With this approach, the design space can be reduced and an engineering-accepted and manufacturable topology result can be guaranteed.     

Reliability-based topology optimization with uncertainties

This research proposes a reliability-based topology optimization (RBTO) using the finite element method. RBTO is a topology optimization based on probabilistic (or reliability) constraints. Young’s modulus, thickness, and loading are considered as the uncertain variables and RBTO is applied to static and eigenvalue problems. The RBTO problems are formulated and a sensitivity analysis is performed. In order to compute probability constraints, two methods—RIA and PMA— are used. Several examples show the effectiveness of the proposed method by comparing the classical safety factor method.     

An optimization approach for black-and-white and hinge-removal topology designs

An optimization approach for black-and-white and hinge-removal topology designs is studied. To achieve this motive, an optimal topology allowing grey boundaries is found firstly. When a suitable design has been obtained, this solution is then used as a starting point for the follow-up optimization with the goal to free unfavorable intermediate elements. For this purpose, an updated optimality criterion in which a threshold factor is introduced to gradually suppress elements with low density is proposed. The typical optimality method and new technique proposed are applied to the design procedure sequentially. Besides, to circumvent the one-point hinge connection problem producing in the process of freeing intermediate elements, a hinge-removal strategy is also proposed. During the optimization, the binary constraints on design variables are relaxed based on the scheme of solid isotropic material with penalization. Meanwhile, the mesh-independency filter is employed to ensure the existence of a solution and remove well-known checkerboards. In this way, a solution that has few intermediate elements and is free of one-point hinge connections is obtained. Finally, different numerical examples including the compliance minimization, compliant mechanisms and vibration problems demonstrate the validity of the proposed approach.     

Level set-based isogeometric topology optimization for maximizing fundamental eigenfrequency

Frontiers of Mechanical Engineering - Maximizing the fundamental eigenfrequency is an efficient means for vibrating structures to avoid resonance and noises. In this study, we develop an...     

拓扑和形状集成优化设计

将拓扑优化、形状优化、有限元分析和计算机辅助设计加以有机集成,构建了优化设计模型;利用几何重构技术,拟合拓扑优化后的边界;在形状优化中,将设计变量定义为B样条曲线或曲面的控制顶点的运动,建立了边界节点移动速度场计算方法,有效地控制节点的运动,给出了相应的算法和计算表达式,寻求较快的搜索方向,以合理速度分布使形状变为最佳.通过设计实例,证明了文中模型的合理性和方法的有效性.     

Connected morphable components-based multiscale topology optimization

Frontiers of Mechanical Engineering - The advances of manufacturing techniques, such as additive manufacturing, have provided unprecedented opportunities for producing multiscale structures with...     

平顶链安装方案的优化设计

提出平项链传输的常见问题,从运行轨道、侧面板及其固定轴的设计、输送带主动轮及从动轮固定板的设计以及链板轮的设计出发,介绍一款平顶链安装的优化设计方案,并阐述其使用效果。     

An incremental micromechanical scheme for nonlinear particulate composites

A general incremental micromechanical scheme for the nonlinear behavior of particulate composites is presented in this paper. The advantage of this scheme is that it can reflect partly the effects of the third invariant of the stress on the overall mechanical behavior of nonlinear composites. The difficulty involved is the determination of the effective compliance tensors of the anisotropic multiphase composites. This is completed by making use of the generalized self-consistent Mori–Tanaka method which was recently developed by Dai et al. (Polymer Composites 19 (1998) 506–513; Acta Mechanica Solida 18 (1998) 199–208). Comparison with existing theoretical and numerical results demonstrates that the present incremental scheme is quite satisfactory. Based on this incremental scheme, the overall mechanical behavior of a hard-particle reinforced metal matrix composite with progressive particle debonding damage is investigated.     

A new two-degree-of-freedom level control scheme

In this paper, a two-degree-of-freedom level control scheme for delay free processes is analyzed. The nominal performance and robustness are examined. And sufficient and necessary conditions for robust stability are derived. An alternative level control scheme is developed for processes with dead time and suboptimal controllers that can produce smooth response are derived analytically based on the internal model control. The scheme has an important feature in that it is simple and transparent in design and in the corporation of performance and robust stability issues. Numerical examples are provided to compare the proposed scheme with those developed.