An experimental method to investigate the load path in a vehicle body frame under certain condition is presented. The mechanical characteristic of vehicle frame is analyzed through strain gauge measurements of stress state at every corner of the key measuring sections. Stress composition is adopted to describe load distribution and internal moment is employed to represent load transfer. Load-carrying factor(LCF) and Christiansen uniformity coefficient(CUC) are used to evaluate the load-carrying capacity of the vehicle body frame. Based on the concept of load path, a modification plan for the vehicle body frame is proposed. The results show that bending stress can be treated as the principle evaluation index of load distribution, and warping stress can be a supplementary tool to observe the direction of load path. In the torsional condition, longitudinal members carry major portions of loads, transverse members and pillar members constitute the anti-torsional rings to share and discharge loads. The anti-torsional rings should exist in the frontal cabin, passenger cabin and rear cabin of vehicle body. If any anti-torsional ring is missing, the load-carrying capacity of the vehicle frame body would be sharply weaken. In the modified version, the load-carrying capacity and the load-distribution uniformity increase of 18.71% and 14.89% respectively. Load path analysis has an essential practical value for vehicle body structure design.
TIAN Linli
,
GAO Yunkai
,
AN Xiuzhe
. Experimental Research on Load Path in Vehicle Frame Bodies[J]. Journal of Mechanical Engineering, 2016
, 52(10)
: 103
-112
.
DOI: 10.3901/JME.2016.10.103
[1] 兰凤崇,赖番结,陈吉清,等. 考虑动态特性的多工况车身结构拓扑优化研究[J]. 机械工程学报,2014,50(10)：122-128.
LAN Fengchong,LAI Fanjie,CHEN Jiqing,et al. Multi-case topology optimization of body structure considering dynamic characteristic[J]. Journal of Mechanical Engineering,2014,50(10)：122-128.
[2] MARHADI K,VENKATARAMAN S. Comparison of quantitative and qualitative information provided by different structural load path definitions[J]. International Journal for Simulation and Multidisciplinary Design Optimization,2009,3(3)：384-400.
[3] BURR A H,CHEATHAM J B. Mechanical analysis and design [M]. NJ：Prentice Hall,1995.
[4] JUVINALL R C,MARSHEK K M. Fundamentals of machine component design[M]. New York：J. Wiley,1991.
[5] 陈贻伍. 力流法及其在机械设计中的应用[J]. 中国有色金属学报,1994,94(2)：94-96.
CHEN Yiwu. Load path and its application to the mechanical design[J]. Transactions of Nonferrous Metals Society of China,1994,94(2)：94-96.
[6] THAMM F. The role of the stress trajectories as an aid in the choice of the suitable shape of load-bearing structural elements of engines and structure[J]. Mechanical Engineering,2000,44(1)：171-183.
[7] KELLY D,ELSLEY M. A procedure for determining load paths in elastic continua[J]. Engineering Computations,1995,12(5)：415-424.
[8] KELLY D,HSU P,ASUDULLAH M. Load paths and load flow in finite element analysis[J]. Engineering Computations,2001,18(1-2)：304-313.
[9] KELLY D,TOSH M. Interpreting load paths and stress trajectories in elasticity[J]. Engineering Computations,2000,17(2)：117-135.
[10] KELLY D W,REIDSEMA C A,LEE M C. An algorithm for defining load paths and a load bearing topology in finite element analysis[J]. Engineering Computations,2011,28(2)：196-214.
[11] HARASAKI H,ARORA J. A new class of evolutionary methods based on the concept of transferred force for structural design[J]. Structural and Multidisciplinary Optimization,2001,22(1)：35-56.
[12] HARASAKI H,ARORA J S. New concepts of transferred and potential transferred forces in structures[J]. Computer Methods in Applied Mechanics and Engineering,2001,191(3)：385-406.
[13] HARASAKI H,ARORA J. Topology design based on transferred and potential transferred forces[J]. Structural and Multidisciplinary Optimization,2002,23(5)：372-381.
[14] HOSHINO H,SAKURAI T,TAKAHASHI K. Vibration reduction in the cabins of heavy-duty trucks using the theory of load transfer paths[J]. JSAE Review,2003,24(2)：165-171.
[15] OKANO Y,MATSUNAGA T,MARUYAMA S,et al. Load path analysis of vehicle body structures under eigenmode deformation of bending vibration[R]. SAE,2009-01-0770,2009.
[16] 高云凯,李翠,崔玲,等. 力流分析法在大型客车车身结构分析上的应用[J]. 汽车技术,2009(12)：8-11.
GAO Yunkai,LI Cui,CUI Ling,et al. The application of load path analysis in the large sized bus body structure analysis[J]. Automobile Technology,2009(12)：8-11.
[17] KOMAROV V A,WEISSHAAR T A. New approach to improving the aircraft structural design process[J]. Journal of Aircraft,2002,39(2)：227-233.
[18] CHRISTIANSEN J. The uniformity of application of water by sprinkler systems[J]. Agricultural Engineering,1941,22(3)：89-92.
[19] MARHADI K S,VENKATARAMAN S,WONG S A. Load redistribution mechanism in damage tolerant and redundant truss structure[J]. Structural and Multidisciplinary Optimization,2011,44(2)：213-233.
