基于iSIGHT平台的倾斜冲击射流传热特性优化

为了研究和优化半封闭倾斜射流中击移动平板的传热性能,采用iSIGHT与CFD软件的联合仿真,根据多岛遗传算法动态调整射流角度和平板移动速度,进行狭缝湍流冲击射流的数值模拟.结果表明,平板表面的传热效果主要是由板速决定的,低速时高角度下的平板表面的平均努塞尔数较高;初始设计时流场左侧的回流区和二次回流区消失,优化后的流场结构得到改善,移动平板表面的平均努塞尔数比初始设计结果提高7.62％,热传导更加均匀.     

基于Matlab和iSIGHT的弹道曲线拟合方法

借助Matlab和iSIGHT软件平台强大的功能，优化不同时间点上阻力系数的修正系数，从而实现多管火箭弹系统（MLRS）速度曲线和弹道曲线的最优拟合．根据飞行力学方程，采用Matlab软件建立远程火箭弹的六自由度弹道仿真模型，解算理论弹道，得出实测弹道和理论弹道的偏差信息．采用在不同时间点增加阻力系数修正系数的方法拟台速度-时间曲线和位置-时间曲线．借助iSIGHT的优化设计功能，得到允许误差下的最优拟合结果．     

基于iSIGHT平台翼型气动优化CAD/CFD集成技术研究

传统的翼型设计中,CFD大多用来检验设计结果,而不是驱动翼型优化设计。两者基本上处于孤岛状态,没有实现有机的集成。为使CFD更好的应用到翼型优化设计,实现翼型设计/仿真的协同优化设计,需要针对现有的仿真分析软件和设计模型,利用集成优化平台进行流程集成和数据集成。采用集成优化平台iSIGHT实现了翼型参数化程序、UG建模软件、CFD计算分析软件Fluent之间的数据集成与过程集成,从而为基于翼型的多学科协同优化研究打下了基础。     

基于iSIGHT的鼓式制动器多目标优化设计

以鼓式制动器效能因素最大和制动鼓体积最小为目标,对鼓式制动器进行多目标优化设计,利用iSIGHT集成的多目标优化遗传算法,得到多目标优化问题的Pareto最优解集,再利用Pareto最优解集专用后处理工具EDM,找到最合适的折衷解.     

基于iSIGHT的湿式多盘制动器稳健设计

传统的结构设计优化大多不能满足可靠性和稳健性要求,原因在于没有考虑各种不确定性因素,因此实际工程结构设计时必须考虑可靠性和稳健性。利用iSIGHT软件中的6σ稳健设计优化研究了基于不确定性的湿式多盘制动器优化设计。     

Decomposition method of complex optimization model based on global sensitivity analysis

The current research of the decomposition methods of complex optimization model is mostly based on the principle of disciplines, problems or components. However, numerous coupling variables will appear among the sub-models decomposed, thereby make the efficiency of decomposed optimization low and the effect poor. Though some collaborative optimization methods are proposed to process the coupling variables, there lacks the original strategy planning to reduce the coupling degree among the decomposed sub-models when we start decomposing a complex optimization model. Therefore, this paper proposes a decomposition method based on the global sensitivity information. In this method, the complex optimization model is decomposed based on the principle of minimizing the sensitivity sum between the design functions and design variables among different sub-models. The design functions and design variables, which are sensitive to each other, will be assigned to the same sub-models as much as possible to reduce the impacts to other sub-models caused by the changing of coupling variables in one sub-model. Two different collaborative optimization models of a gear reducer are built up separately in the multidisciplinary design optimization software iSIGHT, the optimized results turned out that the decomposition method proposed in this paper has less analysis times and increases the computational efficiency by 29.6%. This new decomposition method is also successfully applied in the complex optimization problem of hydraulic excavator working devices, which shows the proposed research can reduce the mutual coupling degree between sub-models. This research proposes a decomposition method based on the global sensitivity information, which makes the linkages least among sub-models after decomposition, and provides reference for decomposing complex optimization models and has practical engineering significance.     

基于iSIGHT的变循环发动机性能优化

通过对变循环发动机结构形式和工作机理的分析研究,依照模块化合成程序的计算流程,给出了变循环发动机数学模型,利用面向对象的C++程序语言发展了基于部件类的变循环发动机数值仿真软件。利用商用软件iSIGHT的多学科优化能力,该仿真软件具有可视化操作界面,具备进行设计点的性能仿真计算、非设计点特性仿真计算以及设计点任务分析的仿真计算的能力。基于iSIGHT优化平台,对变循环发动机的性能进行了优化分析。     

基于iSIGHT平台DOE方法的柴油机喷油器结构优化设计

喷油器是柴油机燃油系统的关键部件之一。采用传统的优化设计方法往往不能全面分析多个参数之间的相互影响与交互效应,进而不能得到全面的系统最优解。本文借助多学科优化软件iSIGHT的试验探索与优化算法,以衡量喷油器雾化质量的索特平均直径、油束锥角及油束贯穿距3个主要性能参数作为优化目标,对喷油器结构进行了优化设计。     

数控机床主轴的多目标优化设计

对数控机床主轴的机构参数优化问题进行了研究。提出了一种以主轴重量、主轴伸出端的扰度为目标的结构参数多目标优化方法。研究了利用多学科优化设计软件iSIGHT对数控机床主轴进行多目标优化设计的方法步骤,并对一个简化的机床主轴模型进行了多目标优化设计,得到Pareto最优解集。研究表明,基于Pareto最优解的方法更适合于数控机床主轴的优化设计;利用iSIGHT进行优化设计,可以简化求解过程,具有一定的工程实用价值。     

Interdigitation for effective design space exploration using iSIGHT

Optimization studies for nonlinear constrained problems (i.e. most complex engineering design problems) have repeatedly shown that (i) no single optimization technique performs best for all design problems, and (ii) in most cases, a mix of techniques perform better than a single technique for a given design problem. iSIGHT^TM is a generic software framework for integration, automation, and optimization of design processes that has been developed on the foundation of interdigitation: the strategy of combining multiple optimization algorithms to exploit their desirable aspects for solving complex problems. With the recent paradigm shift from traditional optimization to design space exploration for evaluating “what-if” scenarios and trade-off studies, iSIGHT has grown from an optimization software system to a complete design exploration environment, providing a suite of design exploration tools including a collection of optimization techniques, design of experiments techniques, approximation methods, and probabilistic quality engineering methods. Likewise, the interdigitation design methodology embodied in iSIGHT has grown to support the interdigitation of all design exploration tools for effective design space exploration. In this paper we present an overview of iSIGHT, past and present, of the interdigitation design methodology and its implementation for multiple design exploration tools, and of an industrial case study for which elements of this methodology have been applied. Received December 30, 2000