Research On Crack Identification Of Parts Based On Resonance Acoustic Nondestructive Testing Technology

In recent years,with the rapid development of automotive industry,the quality requirements of automotive parts are getting higher and higher,especially the identification of serious defects such as cracks is becoming more and more important.Because in the casting production line,technicians often inspect the surface defects,weight detection and size detection of workpieces by visual inspection.In this paper,a fast and efficient nondestructive testing technology for foundry production line is proposed.In this paper,based on resonance method,non-destructive testing technology for structural damage is studied by defect detection and identification through natural frequency analysis of vibration and sound signals.This paper mainly studies the following aspects:Firstly,by consulting a large number of domestic and foreign literature and papers,the commonly used nondestructive testing technologies are studied,and the applicability,advantages and disadvantages of different nondestructive testing technologies are analyzed and compared.By comparing the commonly used methods and techniques of damage identification of vibration structures,a detailed theoretical analysis of the application of the fundamental principles of resonance acoustics to non-destructive testing is carried out.The experimental platform for vibration testing is built,and the contents and key points of the experimental scheme are described in detail.The causes of casting crack defects of brake pump brake support are briefly introduced.The basic theory of multi-scale analysis of wavelet and wavelet packet is discussed emphatically.Various kinds of wavelet basis functions are introduced in detail.According to the experimental signal,the optimal wavelet basis is determined by means of root mean square error and signal-to-noise ratio.According to the denoising steps of wavelet packet,the noise added to the signal is denoised,and good results are achieved.Finally,the qualified range of the first five natural frequencies of brake pump brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake brake bra The experimental results show that the crack can be identified by the natural frequency index,and the more serious the crack damage is,the easier it is to identify.Therefore,the cracks of structural parts can be quickly detected.