A Study Of The Reliability Of Vehicle Part Tested By Road Simulation Detection

Vehicle steering knuckle on vehicle chassis and suspension structure is complex, poorworking conditions but is still a very important part, which has always been the object ofstudy in automotive safety. Knuckle’s fatigue damage is often difficult to detect, but thelong-term use for it will lead to a potential problem that the fatigue damage will endanger thesafety of passengers and pedestrians. In order to explore the fatigue reliability detectionmethods for automotive parts, this paper relies on the funding of key disciplines project ofSouth China University of Technology College, Guangzhou, with the provided of a vehiclecompany of an MPV’s front suspension knuckle, use it as the research object. Loadingcertern road spectrum on it to figure out its fatigue life under to explore detection methodsthat can be applied to practical automotive parts to fatigue reliability. This paper intends tocarry out the following aspects practice:(1)Using the three-dimensional coordinate scanner to reverse scan the knuckle, the useof reverse engineering in order to create complete digital model of the steering knuckle andexpect it can be as close as the physical model of the steering knuckle, so as to obtain moreaccurate calculation parameters for the latter vehicle simulation and fatigue analysis. Thensimplifying the knuckle appropriately, and neglecting some unimportant details that will notaffect the knuckle’s property．After that，meshing the digital model with tetrahedral mesh byHypermesh，and figuring out its first six grade flexible modal shapes and modal frequencies，then exporting its modal neutral file(MNF) for building the rigid-flexible coupling model offront suspension．(2)According to Adams’ characteristic in building model, firstly building all kinds ofsubsystem of the MPV chasis with the chasis’ parameters，and the rigid-flexible couplingmodel of the front Macpherson suspension．Then building a full vehicle model with virtualtestrig by the Ride module that provided by Adams/Car．(3)By analyzing the building method of a road spectrum to find out that kind of roadspectrum that we need. With the nation’s standard file, build a road spectrum to load on thefull vehicle model, so as to get the stress time histroy of the knuckle that can be use to fatigueanalysis. (4)Loading the stress time history circularly to the knuckle model in MSC.Fatigue，tosimulate the vehicle driving on a long road of certain grade．With the theories of linearsummation damage theory and rain-flow counting method，figure out which area of theknuckle is easy to be broken. Then we can give advise for vehicle driving and provide a easyway to detect vehicle parts’ fatigue life on certain grade of road.