An Intelligent Response Surface Methodology for Modeling of Domain Level Constraints

An effective modeling method of domain level constraints in the constraint network for concurrent engineering （CE） was developed. The domain level constraints were analyzed and the framework of modeling of domain level constraints based on simulation and approximate technology was given. An intelligent response surface methodology （IRSM） was proposed, in which artificial intelligence technologies are introduced into the optimization process. The design of crank and connecting rod in the V6 engine as example was given to show the validity of the modeling method.     

Forming path optimization for press bending of aluminum alloy aircraft integral panel

Because of the light weight, high stiffness and high structural efficiency, aluminium alloy integral panels are widely used on modern aircrafts. Press bend forming has many advantages, and it becomes a significant technique in aircraft manufacturing field. In order to design the press bend forming path for aircraft integral panels, we propose a novel optimization method which integrates the finite element method (FEM) equivalent model based on our previous study, the artificial neural network response surface, and the genetic algorithm. First, a multi-step press bend forming FEM equivalent model is established, with which the FEM experiments designed with Taguchi method are performed. Then, the back-propagation (BP) neural network response surface is developed with the sample data from the FEM experiments. Further more, genetic algorithm (GA) is applied with the neural network response surface as the objective function. Finally, experimental and simulation verifications are carried out on a single stiffener specimen. The forming error of the panel formed with the optimal path is only 5.37% and the calculating efficiency has been improved by 90.64%. Therefore, this novel optimization method is quite efficient and indispensable for the press bend forming path designing.     

Structural Optimization of Hatch Cover Based on Bi-directional Evolutionary Structure Optimization and Surrogate Model Method

Weight reduction has attracted much attention among ship designers and ship owners. In the present work, based on an improved bi-directional evolutionary structural optimization (BESO) method and surrogate model method, we propose a hybrid optimization method for the structural design optimization of beam-plate structures, which covers three optimization levels: dimension optimization, topology optimization and section optimization. The objective of the proposed optimization method is to minimize the weight of design object under a group of constraints. The kernel optimization procedure (KOP) uses BESO to obtain the optimal topology from a ground structure. To deal with beam-plate structures, the traditional BESO method is improved by using cubic box as the unit cell instead of solid unit to construct periodic lattice structure. In the first optimization level, a series of ground structures are generated based on different dimensional parameter combinations, the KOP is performed to all the ground structures, the response surface model of optimal objective values and dimension parameters is created, and then the optimal dimension parameters can be obtained. In the second optimization level, the optimal topology is obtained by using the KOP according to the optimal dimension parameters. In the third optimization level, response surface method (RSM) is used to determine the section parameters. The proposed method is applied to a hatch cover structure design. The locations and shapes of all the structural members are determined from an oversized ground structure. The results show that the proposed method leads to a greater weight saving, compared with the original design and genetic algorithm (GA) based optimization results.     

Ship appearance optimal design on RCS reduction using response surface method and genetic algorithms

Radar cross section (RCS) reduction technologies are very important in survivability of the militarynaval vessels. Ship appearance shaping as an effective countermeasure of RCS reduction redirects the scatteredenergy from one angular region of interest in space to another region of little interest. To decrease the scatteringelectromagnetic signals from ship scientifically, optimization methods should be introduced in shaping design.Based on the assumption of the characteristic section design method, mathematical formulations for optimalshaping design were established. Because of the computation-intensive analysis and singularity in shapingoptimization, the response surface method (RSM) combined genetic algorithm (GA) was proposed. The poly-nomial response surface method was adopted in model approximation. Then genetic algorithms were employedto solve the surrogate optimization problem. By comparison RCS of the conventional and the optimal design,the superiority and effectiveness of proposed design methodology were verified.Ky words: radar cross section (RCS); characteristic section design method; response surface method; genetic algorithm (GA) was proposed. The polynomial response surface method was adopted in model approximation. Then genetic algorithms were employed to solve the surrogate optimization problem. By comparison RCS of the conventional and the optimal design, the superiority and effectiveness of proposed design methodology were verified.     

A new approach of intelligent design and optimization for shell nosing

Preform design for shell nosing product without machining the inner surface after forming is an experience-extensive work. Generally, the initial design needs to be modified and simulated consequently to get proper preform and nosing die, and the iterative process is time consuming. This paper puts forward a new approach, in which the suitable initial design can be obtained by knowledge-based intelligent technology and the optimal design can be acquired by finite element method (FEM) based geometrical modification. With the CAX object model as the bridge of CAD and CAE, the CAD model with simulation knowledge can be transferred into CAE automatically, and the CAE result can be automatically utilized as well. Based on the comparison between the simulated shape and the desired shape, the dissatisfactory area will be modified. A new simulation and modification process will be carried out based on the modified design. The process is repeated iteratively to get the optimal design. This approach utilizes the commercial CAD and CAE software, without the need of complex back-forward FEM procedures. Based on the new approach, an in-home intelligent shell nosing design and optimization system is developed, and a case study proves that this system can reach a reasonable design efficiently.     

Robust Optimization Design of Metro Handrails

This paper presents the robust design and response surface method(RSM) based on finite element analysis for the optimization design of metro handrails. The response surface can be created for each output parameter. Sequential quadratic programming is used for the optimization of metro handrails. Taguchi design is employed to investigate the sensitive controlling factors for the strength and mass of metro handrails, by taking the material density, the column and cross bar thickness as controlling factors, and the acceleration, the elastic modulus and the fluctuation of material density as uncontrollable factors. Then, the best combination of controlling factors is found. The results by different methods show that the method of Taguchi design can improve the robustness of the structural performance and reduce the mass.     

基于改进响应面法和Matlab-Adams的麦弗逊悬架优化

基于Adams和Matlab应用改进响应面法对悬架结构参数进行了优化。在Adams/Insight软件中进行了设计参数的灵敏度分析。针对灵敏度较大的设计参数,建立了车轮定位参数在车轮跳动过程中最大变化量的二阶响应面近似数学模型,并对该模型进行了可靠性分析。应用编程实现对响应面数学模型的优化求解,对优化前后的仿真结果进行了对比。对比结果显示了该方法具有较好的准确性和有效性。     

基于模态振型叠加的结构振动形状优化研究

采用结构模态振型来定义结构的形状优化参数模型,以一组结构模态振型的叠加来重构结构表面形状,以结构振动响应为目标函数,采用遗传算法优化配置各阶模态振型的参与因子来优化结构形状,以达到降低结构振动响应水平的目的.以几何平板、半圆柱曲面为研究对象,计算结果表明该方法可以有效降低结构振动响应水平.     

白车身轻量化的一种混合优化策略

以某轿车白车身为研究对象,综合考虑弯曲、扭转刚度和模态指标的性能要求,提出一种基于近似模型寻优和灵敏度分析统筹协调变量的混合优化策略.算法同时考虑构造近似模型与灵敏度,对模型进行全局最优化搜索及仿真验证,并根据灵敏度分析所得贡献率,适当调整变量取值,最终使白车身结构的轻量化达到7.51％.结果表明,混合优化策略能够明显提高白车身轻量化设计的效率.     

基于模糊理论的车辆变刚度弹簧组可靠性优化设计

为提高变刚度弹簧组的设计质量,在传统优化设计方法的基础上,应用模糊设计理论和可靠性设计理论,建立了当弹簧应力和强度分别为随机变量和模糊变量时,综合考虑静强度、疲劳强度、稳定性、质量等因素的变刚度弹簧组的模糊可靠性优化设计模型.以货车某新型变刚度弹簧组为研究对象,利用建立的模型对其进行了优化设计分析,计算结果显示,空重车静挠度分别比原设计方案提高了5.4和3.2 mm,同时还使其总质量降低了约15.8%,表明所建立的模糊可靠性优化设计模型能满足设计要求.      

公路主枢纽站场总体布局方案优选模型及算法

在公路主枢纽站场总体布局中 ,可采用多种方法得出若干个布局方案 ,但方案优选是一件复杂的工作 .笔者利用系统工程的方法建立了方案优选模型 ,并对判断矩阵构成、一致性检验及处理、层次排序针对问题特性提出了算法 ,还给出了应用程序框图及程序特点 .模型及算法对公路主枢纽站场布局规划、初步设计中的方案变更及其相关规划设计项目有应用价值     

考虑软弱下卧层及沉降影响的独立基础优化设计

笔者讨论了独立基础在考虑强度和变形条件下的优化设计 .导出了确定独立基础底面尺寸的优化数学模型 ,导出了偏心荷载作用下基础的高度和底面配筋的计算公式 ,求解优化解采用最优化方法的复合形法和罚函数法 .通过基础实例和工程实例的计算表明优化设计可以节省材料和工程量 5 %～ 1 6 % .所以将本文优化方法用于基础设计 ,会产生较大的经济效益 .     

Uncertainty Quantification for Structural Optimal Design Based on Evidence Theory

Uncertainty design can take account of aleatory and epistemic uncertainty in optimal processes.Aleatory uncertainty and epistemic uncertainty can be expressed as evidence theory uniformly, and evidence theory is used to describe the uncertainty. Transferring and response with evidence theory for structural optimal design are introduced. The principle of response evaluation is also set up. Finally, the cantilever beam in a test system is optimized in the introduced optimization process, and the results are estimated by the evaluation principle. The optimal process is validated after the optimization of beam.     

Particle swarm approach for structural optimization of battleship strength deck under air blast

This paper presents the implementation and application of a modified particle swarm optimization （PSO） method with dynamic adaption for optimum design of a battleship strength deck subjected to non-contact explosion. The numerical simulation process is modified to be more computationally efficient so that the task is realizable. The input variables are the thickness of plates and the dimensions of stiffeners, and the total structural mass is chosen as the fitness value. In another case, the response surface method （RSM） is introduced and combined with PSO （PSO-RSM）, and the results are compared with those obtained by the traditional PSO approach. It is indicated that the PSO method can be well applied in the optimum design of explosion-loaded deck structures and the PSO-RSM methodology can rapidly yield optimum designs with sufficient accuracy.     

基于双响应面法和BBD的车辆悬架系统稳健设计

选用某种型号车辆的麦弗逊悬架系统,探讨悬架系统设计中同时考虑车辆的操纵稳定性和乘客的乘座舒适性问题,运用ADAMS软件对麦弗逊悬架进行建模并对其进行空间运动学定义.将悬架系统的结构尺寸视为可控因素,刚度和阻尼为不确定因素.通过对该悬架的一系列跳动分析和试验仿真得出对悬架的跳动特性影响较大的关键点,运用box-behnken de?sign(BBD)试验方法安排试验,采用稳健设计中的双响应面法对车辆悬架系统进行稳健性分析.为车辆悬架系统的研究提供了一种新的方法.     

Combustion optimization model for NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> reduction with an improved particle swarm optimization

Abstract: This paper focuses on the combustion optimization to cut down NO _x emission with a new strategy. Firstly, orthogonal experimental design (OED) and chaotic sequences are introduced to improve the performance of particle swarm optimization (PSO). Then, a predicting model for NO _x emission is established on support vector machine (SVM) whose parameters are optimized by the improved PSO. Afterwards, a new optimization model considering coal quantity and air quantity along with the traditional optimization variables is established. At last, the operating parameters are optimized by the improved PSO to cut down the NO _x emission. An application on 600MW unit shows that the new optimization model can cut down NO _x emission effectively and maintain the load balance well. The NO _x emission optimized by the improved PSO is lowest among some state-of-the-art intelligent algorithms. This study can provide important guides for the low NO _x combustion in the power plant.     

场面航空器滑行时空协同优化模型

引入双层规划方法, 研究了场面航空器在滑行道系统中的滑行调度问题; 考虑了成本与冲突对场面航空器运行效率和安全的影响, 以航空器推出延迟时间与滑行路径作为决策变量, 以航空器在滑行道系统中滑行过程无冲突与场面航空器的总滑行距离最短为目标函数, 构建了场面航空器滑行时空协同优化模型; 针对航空器滑行道调度问题的特点, 设计了适用于航空器滑行时空协同优化模型的双层规划算法, 以降低场面航空器滑行距离和等待时间; 为了验证航空器滑行时空协同优化模型及算法的有效性, 对比了先到先服务调度方案的计算结果, 分析了滑行等待时间与滑行距离对场面航空器运行效率的影响。研究结果表明: 场面航空器滑行时空协同优化模型与先到先服务的航空器调度方案相比, 保证了航空器滑行过程无冲突, 将16架次航空器的总滑行距离从40 690 m降至37 700 m, 降低了8%;航空器平均运行时间为254 s, 提升了滑行道系统的整体运行效率; 在复制组数为100与变异概率为0.4的条件下, 采用场面航空器滑行时空协同优化模型能够在412 s内获得最优解, 求解效率与收敛性显著。可见, 采用场面航空器时空协同优化模型在保障航空器滑行安全的前提下, 能有效提高场面航空器滑行调度效率, 降低航空器运行成本, 能够为繁忙机场滑行道调度提供决策支持。      

Research on the Lightweight Design of Body-Side Structure Based on Crashworthiness Requirements

Crashworthiness is the most significant variable during lightweight design of vehicle structures.However,crashworthiness studies using the single substructure-based method are limited due to the negligence of interactions among substructures.Thus,a whole structure-based study was conducted for the lightweight design of a body-side structure.In this study,a full finite element model was firstly created and then modified into a simplified model for structural improvements,where the major load-carrying subassemblies were improved from the perspectives of crashworthiness and manufacturing costs.Finally,sensitivity analyses were conducted to further optimize the strength distribution,based on which an adaptive response surface method was employed for thickness optimization of the structure.It is found that through the structural improvements and optimizations,the weight of the structure was significantly reduced even when its crashworthiness was improved.This indicates that the whole structure-based method is effective for lightweight design of vehicle structures.     

基于可靠度的基坑桩锚支护优化设计

根据现实基坑工程中确定性方法存在的不足和缺陷,将可靠度理论运用到基坑桩锚支护优化设计中,建立了施工结构各元件可靠度约束条件下的最小化结构费用优化模型.桩锚支护可靠度约束按照抗倾覆破坏稳定模式、抗坑底隆起稳定模式、抗整体失稳模式三种约束模式分别考虑.根据具体的破坏模式建立了功能函数,结合具体的工程实例,采用JC法计算了不同模式的可靠度指标.计算中编制了Matlab程序,予以实现具体的优化设计.研究结果表明,应用可靠度理论进行基坑优化设计是可行且有效的.     

钢衬里壁板预拉伸成形装备设计及分析

钢采用顶升模架对钢衬里预拉伸,顶升拉力使壁板的拉伸应力接近其屈服强度,同时对壁板外侧实施周向和轴向加劲角钢焊接,保持壁板的曲率半径不变.为确保成形质量,对预拉伸成形装备进行参数化建模,并利用Ansys有限元软件对顶升模架进行静力学分析.结果表明,预拉伸成形装备结构模型及其参数设置合理,为优化设计和钢衬里壁板的建造质量提供了数据保证.钢衬里预拉伸成形理念的提出和实施,打破了传统的制造工艺,为核岛钢衬里建造工艺的新突破.