A Study On Bus Body Structure Concept Design System

Bus body structure is a form of complex spatial high redundant statically indeterminate structure, which is composed by thin-walled bars and is the key assembly of vehicle. Its stress is complex and its structural analysis is difficult. The quality of bus body’s structural performance is fatal to the service life of the bus body. The bus body’s development process can be generally divided into six stages:product planning, conceptual design, technical design, product trial, product testing and production arrangement. Among them, the concept design stage has a great significance to the vehicle development, as it is an important stage to ensure the vehicle performance, design quality and reliability, and is also a stage of concentrated expressing creativity. Bus body structure concept design has the following characteristics:the structural design defects in the concept design stage are hard to be rectified in the subsequent design stages; there is not enough information for using to build the detail model to determine the layout of body structure in bus body structure concept design stage.According to the characteristics of the bus body structure concept design, the Bus Body Structure Concept Design System (BCD-ICAE) is developed and the parameterized concept model of bus body structure is built, based on the research achievements of our research group. Take the concept model as a template, a new bus body structure concept model can be built by modifying the body size parameters in geometric modeling module of BCD-ICAE. By using other modules of BCD-ICAE, the static stiffness, low-modes vibration, sensitivity and optimization design can be calculated and analyzed. The system brings parameterization design concept, CAE analysis and optimization design into the bus body structure concept design stage, and also integrates parameterized modeling, CAE analysis and optimization design as a whole. It realizes the CAE analysis intelligence and blends in the design idea of analysis-driven design, and has a great significance for bus body lightweight design as well.This paper’s first chapter introduces the engineering backgrounds and the significance of this program, and also gives an introduction of the development of related technologies. The second chapter introduces the design concept, the program structure and the build method of Bus Body Structure Concept Design System (BCD-ICAE), and gives a brief introduction of the main UG secondary development tools. The third chapter describes the way of building parameterized concept model and the method of managing the parameters, and gives an introduction on how to build the dialog box, with which can adjust the beam position by using UI Styler. The fourth chapter introduces some examples of using BCD-ICAE to perform the FEA on the bus body concept model, including bending stiffness analysis, torsion stiffness analysis and modal analysis. Then this paper briefly introduces the correlation basic theories. In chapter fifth, the basic theory of optimization method is introduced firstly, then single-objective optimization design and multi-objective optimization design are performed, and the anticipated goal is achieved. The multi-objective optimization design includes stiffness multi-objective optimization design, modal multi-objective optimization design and stiff-modal multi-objective optimization design, In the end of this paper, a method of building detail model of bus body structure concept model is expounded.