The Study Of PG Durability Test Method Based On Vehicle Damage Contribution Analysis

In order to expose the problems in the process of vehicle design quickly,the test engineer needs to carry out accelerated durability test in the PG(Proving Ground).This paper studies the equivalence of Customers' usage to the durability test in PG and the equivalence to the different PG.This research,not only provides more accurate test methods for vehicle durability test,but also provides the corresponding theories for the building of PG.Vehicle durability generally refers to the mileage or time before the vehicle reaches the limit of wear or is used up.Vehicle durability is an critical performance to evaluate the quality of the vehicle.Vehicle durability test refers to accelerated tests conducted in PG to quickly verify the durability of the vehicle.Since the vehicle was put into market as a commodity,the vehicle durability test has developed from the initial public road test to the PG test and the rig test.There are many studies at home and abroad.In order to solve the diversity of customs' usage,an efficient and reasonable durability test which can represent the real customs' usage is formulated with a lot of work.The main work of this paper is as follows:Learning the theory of metal fatigue and understanding the essence of vehicle durability test,transforming the measured time-domain signals into rain-flow cycle matrixes according to the stress-strain cyclic characteristics of materials,and then combining the S-N curve of materials,calculating the damage value of vehicle parts,realizing the parameterization of vehicle durability,and taking the damage as equal.Customs' usage is equivalent to the durability test standard of PG or the durability test standard of the different PG.Customs surveys are needed to determine user usage.According to the target of vehicle development,typical users are screened.Sensors and data acquiring instrument are installed in customs' vehicles to record real-time users' vehicle usage,and the collected user data are analyzed by big data to obtain customs' usage.Then choose a load test vehicle,install sensors on the whole vehicle,collect user data in typical areas of the our country according to the results of user surveys,get the distribution matrix of user's rain flow cycles,use Monte Carlo method to simulate and calculate,determine the rain flow matrix covering 90% of the users with S-N curve.Calculate the damage value as user target.The same one load test vehicle acquires the data of different classes of loads and speeds of different pavements in PG.The same method calculates the damage values of different pavements under different classes loads and speeds.According to the damage equality principle of user's target to the PG,the suitable pavement,loads and speeds in PG are chosen.The cycle mileage and the durability test standard of PG representing 90% of the custom's target are formulated.The vehicle model is built to calculate the frequency response function and the road roughness of strengthen road in PG,and to clarify the load transfer function of the vehicle,so as to find the theories for the making vehicle damage.Combining the amplitude-frequency characteristics of the vehicle and the main frequencies of the strengthened roads in the PG,the vehicle load and speed passing through the PG pavement are adjusted according to customs' usage,and the durability test standard of the PG is improved.At the same time,according to the equal damage principle,the durability test can be carried out in different PG adjusting the load,speed and cycle mileage of the test roads.