Component-oriented decomposition for multidisciplinary design optimization in building design

The potential of Multidisciplinary Design Optimization (MDO) is not sufficiently exploited in current building design practice. I argue that this field of engineering requires a special setup of the optimization model that considers the uniqueness of buildings, and allows the designer to interact with the optimization in order to assess qualities of aesthetics, expression, and building function. For this reason, the approach applies a performance optimization based on resource consumption extended by preference criteria. Furthermore, building design-specific components serve for the decomposition and an interactive way of working. The component scheme follows the Industry Foundation Classes (IFC) as a common Building Information Model (BIM) standard in order to allow a seamless integration into an interactive CAD working process in the future. A representative case study dealing with a frame-based hall design serves to illustrate these considerations. An N-Square diagram or Design Structure Matrix (DSM) represents the system of components with the disciplinary dependencies and workflow of the analysis. The application of a Multiobjective Genetic Algorithm (MOGA) leads to demonstrable results.     

多学科目标兼容优化算法及在MEMS中应用

针对复杂系统的优化设计问题,提出了面向非层级复杂系统的多学科目标兼容优化设计方法,对其基本思路、原理进行阐述。通过在系统级中建立兼容约束和在子系统中构造兼容目标,使各子系统在独立优化设计的同时满足各系统之间的耦合关系,并使系统得到总体的最优解。并将此算法应用于梳齿式微加速度计的设计中,验证了此方法的可行性。     

ATC与CO方法对比及其在卫星设计问题中的应用

针对解析目标分流(analytical target cascading,ATC)与协同优化(collaborative optimization,CO)方法对比及ATC方法在卫星多学科设计优化(MDO)中的应用等问题,研究ATC与CO方法的原理差异;将其应用到两个数学解析算例,通过对比ATC与CO方法在优化过程中系统、子系统问题以及全部问题所需的函数运算次数,可以看出ATC方法可以大大减少子系统问题函数运算次数,计算效率较高.采用ATC方法求解某观测卫星MDO问题得到合理结果,表明了ATC方法的有效性,可为同类航天器MDO问题求解提供参考.     

Model reduction for multidisciplinary optimization - application to a 2D wing

Multidisciplinary optimization (MDO) is a growing field in engineering, with various applications in aerospace, aeronautics, car industry, etc. However, the presence of multiple disciplines leads to specific issues, which prevent MDO to be fully integrated in industrial design methodology. In practice, the key issues in MDO lie in the management of the interconnections between disciplines, along with the high number of simulations required to find a feasible multidisciplinary (optimal) solution. Therefore, in this paper, a novel approach is proposed, combining proper orthogonal decomposition to decrease the amount of data exchanged between disciplines, with surrogate models based on moving least squares to reduce disciplines. This method is applied to an original 2D wing demonstrator involving two disciplines (fluid and structure). The numerical results obtained for an optimization task show its benefits in diminishing both the interfaces between disciplines and the overall computational time.     

Inverse analysis method using MPP-based dimension reduction for reliability-based design optimization of nonlinear and multi-dimensional systems

There are two commonly used analytical reliability analysis methods: linear approximation - first-order reliability method (FORM), and quadratic approximation - second-order reliability method (SORM), of the performance function. The reliability analysis using FORM could be acceptable in accuracy for mildly nonlinear performance functions, whereas the reliability analysis using SORM may be necessary for accuracy of nonlinear and multi-dimensional performance functions. Even though the reliability analysis using SORM may be accurate, it is not as much used for probability of failure calculation since SORM requires the second-order sensitivities. Moreover, the SORM-based inverse reliability analysis is rather difficult to develop.This paper proposes an inverse reliability analysis method that can be used to obtain accurate probability of failure calculation without requiring the second-order sensitivities for reliability-based design optimization (RBDO) of nonlinear and multi-dimensional systems. For the inverse reliability analysis, the most probable point (MPP)-based dimension reduction method (DRM) is developed. Since the FORM-based reliability index (β) is inaccurate for the MPP search of the nonlinear performance function, a three-step computational procedure is proposed to improve accuracy of the inverse reliability analysis: probability of failure calculation using constraint shift, reliability index update, and MPP update. Using the three steps, a new DRM-based MPP is obtained, which estimates the probability of failure of the performance function more accurately than FORM and more efficiently than SORM. The DRM-based MPP is then used for the next design iteration of RBDO to obtain an accurate optimum design even for nonlinear and/or multi-dimensional system. Since the DRM-based RBDO requires more function evaluations, the enriched performance measure approach (PMA+) with new tolerances for constraint activeness and reduced rotation matrix is used to reduce the number of function evaluations.     

Development of Transport Telematics in Europe

This paper gives the definitions of transport telematics and intelligent transport systems (ITS), and describes the basic pre-conditions, situation and market of ITS as well as its applications (products and services) in Europe. Availability of navigable digital maps is emphasized as a major premise. Strategic aspects and key issues for ITS development are explained. Current weaknesses and prospects for ITS services in 20 years are discussed. It is concluded that ITS will make a major contribution to the sustainable development of our society, because it increases our mobility without additional environmental burdens.     

基于GA的仪表新产品功能结构方案推理机模型关键技术研究

虚拟原型逼真设计是近几年发展起来的新技术,主要研究虚拟环境下的产品建模问题以及基于仿真的集成产品和过程设计问题．产品功能结构方案推理机模型是虚拟原型逼真设计实现的关键技术之一．针对功能模块组合方案优化问题的复杂性,研究了基于遗传算法（GA）的功能结构方案推理机模型的实现技术,提出了双链异或杂交算子和自适应调节杂交概率和突变算子选择等算法,结合仪表产品设计应用实例,验证了模型的优越性,并将其应用于仪表新产品开发决策支持系统——仪表LC—QDPDS软件系统中．     

Contactless inspection of planar electronic devices by capacitive coupling: Development of a model describing the sensor signal and its impact on signal post-processing

With regard to a contactless inspection method for planar electronic devices, a model to derive the signal of the employed sensors has been developed. The measurement technique is exclusively based on capacitive coupling and, for instance, applied to the inspection of flat panel displays (FPDs) and printed electronics. To analyze the sensor signals, to evaluate the sensor performance, and to advance signal post-processing, a model of the capacitive coupling is essential. Focussing on configurations of conductor tracks arranged in parallel, the model approach is explained and illustrated in detail. Finite element (FE) simulations and measurements are used to derive the model parameters, to validate the model approach, and to evaluate the model performance. Possible applications to signal post-processing are discussed. As an example, the model is used to reconstruct the voltages applied to individual tracks of a configuration from the sensor signal. Furthermore, the model is extended to configurations of two-dimensionally arranged conductor tracks.     

On the validity of ESO type methods in topology optimization

It is shown on a simple test example that ESO’s rejection criteria may result in a highly nonoptimal design. Reasons for this failure are also discussed. Received September 12, 2000