Research On Fatigue Reliability Of Vehicle Suspension Components

Suspension is the most important parts releated to vehicle travelling safety and comfort, it suffers radom time-varying dynamic loads during driving. Under contious action of such loads, many components would cause dynamic stress, and ultimately cause fatigue failure. In automotive development, fatigue reliability research is essential, while conventional methods such as reliabiltiy test and empirical design are unable to represent the actual usage.Asociated with the project of Tianjin Research Program of Application Foundation and Advanced Technology, based on target vehicle's road load data, by by means of simulation and experiment, researches on fatigue life prediction of components in complex load cases has been carried out. Following works have been done in this paper: Firstly, the thesis briefly introduces the basic theories coorelatively, and the current research situation of vehicle load data and fatigue life prediction in domestic and abroad is also introduced and summaried, also presents the mainly research contents of this thesis. Secondly, preprocessing of the road load data measured by using the wheel force transducer, including sensor calibration analysis, spike data removing, drift term detection and small load processing. Then the load spectrums under the vehicle coordinate system are obtained throuth coordinte transformation, which are prepared as boundary constraints condition for dynamic analysis, and then test datas are analyzed in statistical characters. In considering the flexible connection, dynamic model of vehicle suspension is built based on 3D geometric model. Dynamic response on parts are obtained, which would be provided as a load condition for fatigue life analysis. Finally, damage calculation and fagiue life prediction of steering knuckle have been carried out, and also this thesis analysis the factors affecting the fatigue life of the kunckle.The above research provides a reliable reference on optimized design of vehicle components, and it has theoretical value and engineering significance.