铝合金车身平台的基础性能关联性研究
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摘要
本文中根据模态理论推导出铝合金车身平台的静态刚度、轻量化系数和各阶模态参量之间的定量关系,为前期策划阶段的铝合金车身平台的轻量化设计和性能目标设定提供指导。然后基于有限元模型,提取前50阶模态参数并计算得到铝合金车身平台弯、扭刚度和轻量化系数的近似解,与有限元分析的解的误差仅为4.32%,1.85%和1.78%。由此得出,铝合金车身平台的静态柔度可用各阶模态柔度贡献量之和来逼近。同时发现对弯曲(扭转)刚度贡献量最大的模态阶次即为对应的1阶弯曲(扭转)模态,这一结论可作为弯、扭模态识别的重要途径。最后依据有限元分析和模态理论得到的弯、扭刚度和轻量化系数与试验值进行对比,可明显看出模态理论算法的误差比有限元分析小,弯、扭刚度和轻量化系数的模态理论算法的误差分别为1.85%,1.82%和1.89%。
The quantitative relationships of static stiffness, lightweight factor and modal parameters of aluminum-alloy body platform are derived according to modal theory, to provide a guidance for the lightweight design and the performance objective setting of aluminum-alloy body platform in early concept-design stage. Then based on the finite element model, the former 50 orders of modal parameters are extracted and the approximate solutions of bending stiffness, torsion stiffness and lightweight factor of aluminum-alloy body platform are calculated, which are very close to that of finite element analysis with their relative errors being only 4.32%, 1.85% and 1.78% respectively. So, it can be found that the static compliance of aluminum alloy body platform can be approached by the sum of the modal compliance of each order, and the vibration mode with the most contribution to bending(torsional) stiffness is right the first order bending(torsional) mode, being a conclusion as an important way of modal identification. Finally, the bending and torsional stiffnesses and lightweight factor obtained by finite element analysis and modal theory algorithm are compared with that by test and it is quite evident that the error of modal theory algorithm is smaller than that of finite element analysis. They are as small as 1.85%, 1.82% and 1.89% for bending stiffness, torsional stiffness and lightweight factor respectively.
The quantitative relationships of static stiffness, lightweight factor and modal parameters of aluminum-alloy body platform are derived according to modal theory, to provide a guidance for the lightweight design and the performance objective setting of aluminum-alloy body platform in early concept-design stage. Then based on the finite element model, the former 50 orders of modal parameters are extracted and the approximate solutions of bending stiffness, torsion stiffness and lightweight factor of aluminum-alloy body platform are calculated, which are very close to that of finite element analysis with their relative errors being only 4.32%, 1.85% and 1.78% respectively. So, it can be found that the static compliance of aluminum alloy body platform can be approached by the sum of the modal compliance of each order, and the vibration mode with the most contribution to bending(torsional) stiffness is right the first order bending(torsional) mode, being a conclusion as an important way of modal identification. Finally, the bending and torsional stiffnesses and lightweight factor obtained by finite element analysis and modal theory algorithm are compared with that by test and it is quite evident that the error of modal theory algorithm is smaller than that of finite element analysis. They are as small as 1.85%, 1.82% and 1.89% for bending stiffness, torsional stiffness and lightweight factor respectively.
引文
[1] GRIFFITHS D,AUBERT A,GREEN E,et al.A technique for relating vehicle structural modes to stiffness as determined in static determinate tests[C].SAE Paper 2003-01-1716.
[2] GRIFFITHS D,GREEN E,LIU K.Application of the modal compliance technique to a vehicle body in white[C].SAE Paper 2007-01-2355.
[3] WAHYUNI E,JI T.Relationship between static stiffness and modal stifffness of structures[J].The Journal for Technology and Science,2010,21(2).
[4] MALEN D E.Fundamentals of automobile body structure design[M].USA:SAE International,2011:121-213.
[5] HELSEN J,CREMERS L,MAS P,et al.Global static and dynamic car body stiffness based on a single experimental modal analysis test[C].Proceeding of ISMA2010 Including USD2010.Belgium,2010:2504-2521.
[6] DELEENER J,MAS P,CREMERS L,et al.Extraction of static car body stiffness from dynamic measurements[C].SAE Paper 2010-01-0228.
[7] LüDKE B,PFESTORF M.Functional design of a “lightweight body in white”-how to determine body in white materials according to structural requirements[C].Niobium Microalloyed Sheet Steels For Automotive Applications Edited by TMS (The Minerals,Metals & Materials Society),2006.
[8] 倪振华.振动力学[M].西安:西安交通大学出版社,1989:161-227.
[2] GRIFFITHS D,GREEN E,LIU K.Application of the modal compliance technique to a vehicle body in white[C].SAE Paper 2007-01-2355.
[3] WAHYUNI E,JI T.Relationship between static stiffness and modal stifffness of structures[J].The Journal for Technology and Science,2010,21(2).
[4] MALEN D E.Fundamentals of automobile body structure design[M].USA:SAE International,2011:121-213.
[5] HELSEN J,CREMERS L,MAS P,et al.Global static and dynamic car body stiffness based on a single experimental modal analysis test[C].Proceeding of ISMA2010 Including USD2010.Belgium,2010:2504-2521.
[6] DELEENER J,MAS P,CREMERS L,et al.Extraction of static car body stiffness from dynamic measurements[C].SAE Paper 2010-01-0228.
[7] LüDKE B,PFESTORF M.Functional design of a “lightweight body in white”-how to determine body in white materials according to structural requirements[C].Niobium Microalloyed Sheet Steels For Automotive Applications Edited by TMS (The Minerals,Metals & Materials Society),2006.
[8] 倪振华.振动力学[M].西安:西安交通大学出版社,1989:161-227.