Research On Mapping Relationship Between Load And Damage Of China Standard EMU Frame

In recent years,the expansion of the overall scale and the improvement of the quality of the railway network have promoted the rapid development of China’s economy,and the optimization of economic structure and the upgrading of industrial chain have put forward the new situation and new demand for the high-speed EMU and other rail transit.As a key component of high-speed EMU bogie,the frame reflects the operation performance and ensures the safety of the whole vehicle.Therefore,it is of great significance to study the measured operation load and structural stress response.In this paper,the bogie frame of China Standard EMU is taken as the research object.Based on the measured load and dynamic stress signals of the frame of Daxi Line,the correlation analysis,the establishment of load damage mapping relationship and the extension of load spectrum are completed through data processing.The specific work is as follows:Firstly,the correlation between the load and the stress of different measuring points is established and verified from the analysis of the measured data and the finite element simulation of the frame.The sliding window algorithm is innovatively introduced to process data and optimizes correlation eigenvalues.Under different working conditions and different stress regions,the Pearson correlation coefficients between the load systems of the frame and the stresses at the measuring points are calculated,the correlation in time domain is analyzed.The abstract mapping relationship between load and stress is established,which can be used for the study of load spectrum expansion.Secondly,the phase matrix corresponding to the 20 stress measurement points with the largest measured damage is established and optimized,and its characteristics are analyzed.Together with the transfer coefficient matrix after fixed value correction,a concrete load damage mapping relationship is formed.The phase matrix is used to supplement the phase information,reduce the error between the predicted damage and the measured damage,and ensure the authenticity and reliability of the load spectrum extension.Finally,according to whether the correlation between load and stress is considered,two load spectrum expansion methods suitable for different conditions are proposed and evaluated.Based on the damage consistency,establish the linear relationship between the measured load spectrum and the predicted equivalent stress,define the amplification factor.Two groups of amplification coefficients with different numbers and values are obtained by taking the fatigue allowable stress of welded joints at 70 MPa as the standard.Based on the measured data and model simulation,this paper studies and applies the correlation between measured load and stress,which can provide a reference for more real and reliable load spectrum compilation.