Research On Residual Stress Of Component Based On Energy Analysis Of HHT Vibration Signal

With the rapid development of modern industry and science and technology,people's requirements for the basic characteristics of mechanical components are gradually improved,especially the service life of mechanical components has become the focus of attention.In the actual industrial production,the component after casting,assembly,cutting,welding and other mechanical processing stages,will form a certain amount of residual stress in the internal.The working accuracy,anti-fatigue ability and yield limit of mechanical components will be reduced due to the occurrence of residual stress,which eventually leads to cracks or even irreversible deformation in the actual use process,leading to the service life of mechanical components.Therefore,in engineering practice,choosing the appropriate means to check whether there is residual stress inside the machine plays a vital role in daily life and industrial production.Based on welded steel as the research object,this paper will Hilbert-Huang transform theory is used for welding steel plate vibration signal analysis,the introduction of the definition of the modal energy and modal energy entropy,in the Angle of energy welding steel plate vibration signal is analyzed,as a judgment of residual stress components,a new method to concrete research content is as follows:Firstly,the research background and significance of the subject are described,and the development status of residual stress detection technology at home and abroad is specifically introduced.Elaborate Hilbert-Huang transform theory and its basic concepts,in view of the empirical mode decomposition technique advantages and disadvantages are analyzed,using mirror continuation with improved lumped average combining empirical mode decomposition(ME-MEEMD)algorithm,and through the simulation and analysis show that this method is compared with other decomposition method is highly effective.Then the improved ME-MEEMD decomposition method was used to analyze the vibration characteristics of the mechanical system with multiple degrees of freedom,and it was found that there was a corresponding relationship between the natural vibration mode function and the natural mode function of the mechanical system.The corresponding relationship between them verifies the feasibility of using Hilbert-Huang transform method to analyze vibration signals from the perspective of mechanical vibration analysis,which provides a theoretical basis for the following experiments.Use the DH5922 D dynamic signal acquisition instrument to collect the vibration signal at the point to be measured on the welded steel plate,then perform multiple thermal aging treatments on the welded steel plate until the welding residual stress is eliminated,and collect the vibration signal at the measured point again,using drilling The method is used to measure the residual stress of the steel plate in two states,and obtain the distribution law of the residual stress on the welded steel plate.Finally,the collected vibration signals are analyzed and processed by using the principle of Hilbert-Huang transform.At the same time,the optimized ME-MEEMD decomposition method was used to further analyze and process the relevant vibration signal data and convert it into IMF component group.The ratio of the modal energy of each IMF component to the total energy of the signal was obtained,and the influence of the existence of welding residual stress on the energy distribution in the vibration signal and the total energy of the signal was observed.Then,the modal energy entropy value of vibration signal was further calculated.Taking the modal energy entropy value as the characteristic parameter of vibration signal,the change of modal energy entropy value of vibration signal at the point to be measured of welded steel plate before and after thermal aging treatment was compared.The results show that the method is consistent with the testing results of drilling method,and the welding residual stress on the welded steel plate can be measured correctly,which proves the effectiveness of the method in the direction of component residual stress detection.