Analysis And Optimization Of Body Performance Based On Simplified Mechanical Model In Conceptual Design Phase

Development of automotive body includes conceptual design, detail design,testing and validation, and manufacture phase. In the conceptual design phase, a detailfinite element model cannot be built, which lead to great freedom and blindness. Bodyperformance will be effectively guaranteed and the design risk of early developmentwith less information will be greatly reduced if the simplified mechanical model wasanalyzed for strength, modal, stiffness and crash safety after the simplifiedmechanical model of car body was built according to body shape, general arrangementpoint and other basic data.In this paper, simplified model of car body with beam elements based on modaland stiffness, simplified model of cockpit based on impact and simplified model basedon true joint were built according to body design demand. Modal and strength andstiffness of the simplified model with beam elements based on true joint wasoptimized by hybrid and adaptive metamodeling method, which make a higherprecision since the method combined three approximate models. The contents in thispaper were studied as follows:(1)Status and approaches of the simplified model and key section design of thecar body at home and abroad in the conceptual design phase were researched.(2)In this paper, a simplified mechanical model with beam elements was built forsolving the problem that the detail model cannot be built in conceptual design phase.Then the simplified mechanical model and the detail finite element model wereanalyzed. The result showed that the precision of simplified mechanical model can beguaranteed on the condition that the model can be modified easily and built fast, andhas shorter computing time, which can be used in body analysis and optimization inconceptual design phase.(3)A simplified mechanical model and a detail finite element model of thecockpit were analyzed in the load case of modal, dynamic stiffness and crash safety inthis paper, and the result showed that the error of simplified mechanical model wasacceptable, and it greatly reduced the computing time in the conceptual design phase,which provides guidance for key component design.(4)Since large stress location was existed in joint area, true joint was usuallyused in simplified mechanical model in order to predict whether the joint can satisfy the strength demand. A simplified mechanical model based on true joint was built, andthe model was analyzed and optimized by hybrid and adaptive metamodeling method,and the result showed that the body performance was improved and body weight wasreduced, which has some project significance.