Research On Electromagnetic Ultrasonic Transducer For Bolt Detection

Meanwhile,China in the field of water conservancy and hydropower construction,tunnel construction,railway and road construction,urban infrastructure construction in full swing undertaken to maintain the stability of the soil and rock put forward higher requirements since the founding of New China,the traditional means of support with a steel frame,Arching,etc.is not only complicated and expensive construction supporting effect is very general.Having bolt anchoring technique and supporting effective,easy construction,good economy,etc.,it is rapidly bolt anchoring technique is widely used in the above field of infrastructure,for detecting whether or not each bolt supporting a stiffening effect which It is particularly important.Specific studies are as follows:(1)Research background and significance of the problem will be explained,discussed the magnetostrictive guided wave detection principle,derived equation between the transducer magnetostrictive transducer mechanism and multi-field,using MATLAB software to draw the free and bolts anchored dispersion curve,can provide the theoretical basis for the electromagnetic acoustic transducer unit.(2)Using the finite element simulation software COMSOL Multiphysics dimensional freedom bolt detection model,numerical simulation and experimental embodiment of a pitch-catch electromagnetic ultrasonic transducer parameters selected for study,including driving and receiving a selected diameter of the coil,the exciter end of the receiving end selection bias magnetic field length,ring size selection shielding material thickness,effect of adding a ferromagnetic material on the conversion efficiency.According pitch-catch ultrasound electromagnetic simulation and experimental results obtained by selecting the transducer parameters,not only to enhance the efficiency of electromagnetic ultrasonic transducer transducer can also provide an important basis for future practical application.(3)For the case of detecting the anchoring of the free end of the short distance,the self-excited and self-receiving structures of formula bolt anchoring detection platform,transducer studied self-excited and self-receiving electromagnetic ultrasonic experimentally by selecting the best self since receiving transducer parameters,including self closing selected from the coil diameter and length,,a bias magnetic field to enhance the conversion efficiency of the self-excited and self-receiving electromagnetic ultrasonic transducer,the improved anchoring a bottom end and a defect detection weak echo signals,the echo signals such that characteristics significantly easier to analyze.(4)Detects a free band and the anchor bolt consisting of a pitch-catch defect detection by internet;self-excited and self-receiving-type detection platform anchor bolt,the anchor of the defect is detected at different positions.For the problem of the echo signal contains much noise,variational mode decomposition-Threshold Wavelet denoising algorithm filtering obtained in Comparative conventional filtering algorithms,noise reduction algorithms higher quality paper anchor accuracy of detection.research background and significance of the problem will be elaborate,introduce magnetostrictive spread to guide electromagnetic acoustic transducer research and development related to the current situation.Describes a magnetostrictive waveguide detection principle and the basic concept,the establishment of magnetostrictive transducer equations,solved by the free bolt waveguide dispersion curve detection principle,provide a theoretical basis for the study.