Research On Internal Residual Stress Detection Technology Of Components Based On Vibration Signal

With the rapid development of modern science and technology,people have higher requirements for the fatigue strength and structural stability of mechanical structural parts.However,in the actual production process,various processing techniques will produce a certain degree of residual stress.The existence of residual stress will seriously shorten the service life of the component,affecting the stability and accuracy of its geometrical dimensions.Therefore,the research of residual stress detection technology is especially important for ensuring the structural reliability and safety of components,and it is of great significance for the development of modern industry.In this paper,the research on the relationship between vibration signal and residual stress is carried out in combination with the research on the method and device for detecting residual stress of workpiece based on Hilbert-Huang transform(Jilin key scientific and technological research project).The parameters of vibration signal are extracted and residual.The relationship between stresses is established,providing a new way to detect residual stress.The specific research contents are as follows:Firstly,the domestic and foreign researches of residual stress detection technology are introduced in detail,and the detection of residual stress by Hilbert Huang transform is proposed.The basic theory of empirical mode decomposition and its improved algorithms and deficiencies are discussed.Improved CEEMDAN decomposition method is proposed.The results show that this method is more accurate and efficient.? Then,the vibration characteristics of the single-degree-of-freedom and multi-degree-of-freedom systems are analyzed,and the relationship between the natural vibration modes of the mechanical system and its natural mode function is obtained.The relationship between the natural frequency and its corresponding amplitude and residual stress is theoretically derived.The influence of the residual stress on the vibration parameters of the natural mode is obtained.The natural mode function is combined with the natural vibration mode of the mechanical system.Corresponding relationship proves the feasibility of Hilbert-Huang transform to detect residual stress,which provides powerful theoretical support for subsequent analysis.Secondly,build a vibration test bench,the vibration signal acquisition instrument was used to collect the vibration signals of the untreated and the first thermal aging treatment and the second thermal aging treatment of the welded steel plate,and use the blind hole method to the two welded plates.Residual stress was measured in two states before and after thermal aging treatment,and the residual stress distribution characteristics of the welded plates under different conditions were obtained.Finally,Hilbert spectrum analysis was performed on the IMF components by the Hilbert-Huang transform method,and the characteristic parameters of the signals were extracted to verify the relationship between the natural frequency and its corresponding amplitude and residual stress.The results show that the existence and distribution of residual stress can be detected by the Hilbert-Huang transform method,which proves that this method is real and effective and is very suitable for the residual stress detection of components.