Research On Fatigue Life Of Commercial Vehicle Equilibrium Suspension Based On Actual Load Spectrum

With the development of China’s infrastructure and logistics industry,the sales volume of heavy commercial vehicles has increased rapidly.The fatigue durability of trucks can directly affect the reliability of trucks,and it has received more and more attention from enterprises.In the vehicle research and development phase,endurance analysis of truck’s important components can shorten the product development time and reduce research and development costs.In this paper,the balance suspension is taken as the research object.Firstly,the life of the suspension is evaluated based on the combination of real road test and virtual simulation technology.Secondly,the fatigue cracking problem of the suspension support is optimized to meet the requirements.Finally,the accelerated life program is compiled.The load spectrum greatly shortens the analysis time under the premise that the suspension damage distribution and size are basically the same.According to the analysis target,the test program is formulated,the different test road surfaces are selected,the sensor type is determined according to the measurement signal,the selected data acquisition equipment is selected,and finally the collection system is set up for the actual vehicle test.The original signal obtained by the test cannot be directly used for analysis,and further confirmation of signal validity,resampling,deburring.It prepared for virtual iterative analysis.Finite element model for inertial release analysis of unit loads is established.Based on the measured physical parameters of suspension and bushing,a multi-body dynamics model of rigid-flexible coupling of suspension and half-frame is established in ADAMS.In order to build the model more accurately,the frame is flexible.Combined with the expected signal of the preprocessing,the load spectrum at the suspension bushing is obtained based on virtual iterative method.The fatigue life prediction is carried out in the fatigue simulation software Ncode.The result shows that the thrust rod does not have fatigue problem,and the balance shaft bend is prone to cracking.The local fatigue life analysis is performed based on the strain signal measured by the road test thrust rod,and the accuracy of the simulation result is verified.The final optimization makes the balance shaft fatigue life meet the design requirements.Aiming at the problem that the road durability test takes long time and high cost,a program load spectrum coding method which can accelerate the suspension fatigue test is proposed.Based on the load spectrum of the virtual iteration,the rain flow counting method and the mathematical statistics method are applied to compile the program load spectrum and simplify.The program load spectrum is valid and shortens the analysis time.Aiming at the suspension fatigue problem,this paper designs a set of analysis process,including life prediction,life extension and life acceleration.It is also applicable to the life study of other key parts of automobiles,and has good engineering practical value.