【作者】 丁彦闯；

【导师】 兆文忠；

【作者基本信息】 大连交通大学 ， 机械制造及其自动化， 2008， 博士

【摘要】 当前,随着我国铁路运输的高速、重载化,铁道车辆行业获得了前所未有的发展机遇,同时对车辆的结构设计提出了更高的要求、带来了更大的挑战。铁路车辆是多学科、多领域交叉耦合的复杂产品,尤其对于时速200 km/h以上的高速动车组,其要求性能更高、耦合因素更多。我国的高速车辆在其研制过程中,尽管借鉴了国外许多先进技术,也采纳了铁路大提速以来车辆行业积累下来的许多成熟技术,但是在整体性能上,与国外仍有明显差距;在设计方法上,主要是采用“试算—验证—修改”的传统设计方法,还没有将结构优化设计的理念贯穿于整个设计过程中。因此,本文从不同层面上对铁路车辆结构优化设计的方法及应用进行了详细研究,由概念设计的拓扑优化、详细设计的形状(尺寸)优化到整体设计的多学科优化,将结构优化的设计方法应用到铁道车辆结构设计过程的不同层面上。采用现代优化理论进行结构优化设计,是现代铁路车辆产品设计手段的升华,必将为提升产品质量、缩短开发周期、减少设计盲目性起到重要的推动作用。在对国内外铁路车辆结构优化设计的现状及结构优化发展概况综述的基础上,采用分层次的研究策略,以铁路车辆结构优化设计为研究目标,从概念设计的拓扑优化、详细设计的形状(尺寸)优化到整体设计的多学科优化,分别从优化方法、优化策略、实例验证到典型工程应用,进行了一系列深入研究。归纳起来,本文的主要研究工作如下:(1)系统阐述了结构优化的基本理论,概述了结构优化算法的类型和特点,对常用工程优化算法及多学科优化的方法原理进行了详细分析。(2)针对复杂结构优化设计的效率问题,研究了基于近似模型的优化策略。介绍了试验设计常用的方法和原理;分析了响应面近似模型、kriging近似模型、RBF近似模型及泰勒序列近似的原理和建模要求;给出了近似模型精度的评价标准,并采用算例对RSM、kriging及RBF模型进行了比较。(3)采用变密度法对转向架轴箱转臂进行了拓扑优化设计;针对应力约束问题,并结合实际工程复杂结构的可操作性,采用考虑接触关系的详细有限元模型进行强度验证,保证拓扑优化的实用性。该研究为铁路机车车辆结构概念设计阶段优化设计的开展提供了技术范例。(4)分析了位移敏度和应力敏度的求解原理;建立了高速铝合金车体的有限元模型,按规范进行有限元分析;以板厚为设计变量,在有限元分析基础上计算了车体结构对设计变量的位移敏度和应力敏度;基于敏度的知识信息,给出了结构轻量化的优化方案。为复杂结构基于敏度信息的快速优化设计提供了可操作的实用方案。(5)对内燃动车组废气涡轮增压器压气机叶片进行了多学科优化研究。建立了叶片三维参数化模型,在保证叶片的气动性能基础上,以叶片不同位置截面的分布厚度为设计变量,对结构、振动频率进行了多学科可行一体化优化设计,取得了满足条件的最优结果,这一结果亦有典型示范作用。(6)对铁路车辆主型焊接结构,考虑疲劳损伤约束的多学科优化进行了研究。分析了Goodman疲劳安全系数、线性累积损伤理论以及国外焊接接头的疲劳评估标准(IIW、BS);提出了虚拟疲劳试验的技术路线,在虚拟样机上实施疲劳试验,预测产品的设计疲劳寿命;对焊接结构多学科优化进行研究,提出基于近似模型、提高优化效率的多学科可行法;建立了焊接构架疲劳损伤、结构一体化优化模型;开发了Goodman疲劳安全系数、虚拟疲劳试验损伤计算程序;实现了焊接构架疲劳损伤、结构分析的多软件集成、自动优化技术;并采用基于近似模型的多学科可行方法对焊接构架进行了疲劳损伤结构多学科优化,在满足应力、疲劳安全系数及焊接接头累积损伤约束下,构架质量减轻11.6%,这对车辆轻量化要求下焊接结构的可靠性设计提供了实用参考。本课题得到国家“863”高技术研究发展计划项目:《复杂产品协同设计、仿真、优化一体化平台研究开发及其应用》(项目编号:2006AA04Z160)的资助。更多还原

【Abstract】 China’s railway system is being challenged by higher speed and heavier load which brings great opportunities to the locomotive and rolling stock industry. The structural design of the railway vehicles has become one of the key technology development areas. Railway vehicles are products of multi-disciplinary technologies with lots of coupling, it is particular more complex for those EMUs at speed 200 km/h and higher. The development of China’s high-speed railway vehicles not only benefited from the experience gained from China’s railway speed increases over the years but also the technology advancements throughout the world, however, lots of improvement opportunities remain. The traditional trial and error approach is still practiced widely in design processes, and the concept of structural optimization design is only in its early adoption. This thesis studied in detail the railway vehicle’s structural optimization design and its applications. Structural optimization design is applied to various stages of the design process such as the topological optimization in conceptual design, the shape optimization in detailed design, and the multidisciplinary optimization in the integration design. Multi-level optimization is applied in complex engineering design and the overall performance of the complex engineering products is optimized. With its product quality enhancement, short development cycle, and design efficiency improvement, multi-level, multi-disciplinary structural optimization design is the future of railway vehicle design.This thesis reviewed railway vehicle’s structural optimization design and discussed its recent developments throughout the world. The research work took a multi-level approach, targeted railway vehicle’s structural optimization design, covered topological optimization of conceptual design, shape (size) optimization of detailed design and multidisciplinary optimization of integration design. The thesis also discussed in detail the optimization methodology and strategy, and provided examples and typical applications. The main research areas of the thesis are(1) Detailed discussion of the structural optimization theory, summary of the main structural design algorithms. Detailed discussion of the methodologies and principles for those commonly used engineering optimization algorithms and multidisciplinary optimization.(2) Discussion of the optimization strategy using approximate model for efficiency improvement of complex structural designs. Introduction of Design of Experiment (DOE), response surface approximate model, Kriging approximate model, RBF approximate model, and the Taylor sequence model. Analysis of evaluation criteria for approximate model accuracy and comparison of RSM, Kriging and RBF models through examples.(3) Topological optimization design of the bogie pivoted arm using variable densities. Topological optimization results were ensured by strength test using detailed finite element model with contact relationships accounted, taking into consideration of stress constraint issues and convenience of operation for a real complex structure. The optimization of the structural conceptual design for railway vehicle is made possible.(4) Discussion of the principles of displacement sensitivity and stress sensitivity. Finite element model of a high-speed aluminum alloy body. Finite element analysis using specifications; Using plate thickness as design variables, calculation of vehicle body structure’s displacement sensitivity and stress sensitivity to the design variables in an finite element analysis. The structure weight lightening is achieved using the calculated sensitivities. This chapter provides a good example of fast and optimized design of complex structure using sensitivity information.(5) Multidisciplinary optimization study of the blades of the locomotive diesel engine turbocharger compressor. Three-dimensional parametric model was built for the blades. The most optimized results were obtained by multidisciplinary integrated design on structure and vibration frequency, using blade thickness at different cross-section as design variables, without sacrificing aerodynamic performance of the blades. This result also has typical model role。(6) Multidisciplinary optimization study of welded structure’s reliability upon fatigue. Discussion of Goodman fatigue’s safety coefficient, linear cumulative damage theory, and the international welded joint fatigue evaluation criteria (IIW, BS). Virtual Fatigue Test(VFT) technique is outlined, fatigue test on a Virtual Prototype, predicting designed fatigue life for the products; Multidisciplinary Feasible(MDF) method based on approximation model is proposed, with which optimization efficiency is greatly improved. Optimization model of welded bogie frame is created with considering welded joints fatigue damage and stress constrains. Developed program to calculate Goodman fatigue safety coefficient and welded joints fatigue damage. Integration of multiple programs and automatic optimization are achieved for welded frame fatigue damage and structural analysis. The weight of the welded frame was reduced by 11.6%, using Multidisciplinary Feasible (MDF) method based on approximation model, while satisfying the requirements of stress, fatigue safety coefficient and welded joint cumulative damage. This method provides a useful reference for the reliability design of the lightweight welded vehicle structures.This research is funded by the State "863" high-tech research and development project: "Coordinated design of complex product, simulation and optimization----integrated platform research, development and application" (Project Number: 2006 AA04Z160).更多还原