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The traditional body structure design using statistical method of analogy and experience , focusing on the static properties of the body , consider less dynamic characteristics . Car toward the high-speed development of lightweight , making the body in the research and development stage , it is necessary to focus on the dynamic performance , in order to have a good static and dynamic characteristics . Thus, the dynamic design technology has become very important for the structure of the vehicle body . The dynamic design includes accurate dynamic model and dynamic optimization design of two parts . A domestic car , for example , the use of finite element theory , modal analysis, transient dynamics and design optimization of the dynamic theory of body structure design , specifically the following research : First, according to the finite element model and welding point model to establish the principle of the finite element model of the body-in-white ; analysis and experimental results are compared to the theory of modal and experimental modal and static stiffness , dynamic and static verification of the finite element model with higher accuracy. Secondly , based on the model of the body-in-white , the establishment of a transient dynamic analysis model , analysis of the the body structural vibration excitation of the two road , through the auto-power spectral density analysis : In the frequency range of 4 to 12.5Hz , each measuring point vibration acceleration energy , a greater impact on vehicle ride comfort . Then , the body structure of a first-order reverse modal sensitivity analysis and the torsional stiffness sensitivity analysis , based on the sensitivity analysis results , select 20 both more sensitive plate optimization variables , a first-order torsional mode as the optimization objective , body mass and a bending mode for the constraint variables, to optimize the design of the body structure . And from the modal analysis, stiffness analysis and transient dynamic analysis of three aspects of the optimization results were evaluated , the results showed that : optimized body structure of a first-order torsional mode frequency increases , stiffening , vibration performance improvement ; proved based on sensitivity analysis of the feasibility of selected optimization variables method .
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