Research On Damage Detection In Plates Based On Ultrasonic SH Wave

The plate structure is widely used in the fields of aircraft,vessel and marine engineering.Under the combined action of complex environmental factors and external loads,local structures are very prone to various types of micro-damage,and with the gradual development of damage,it will eventually cause the failure of the structure,so the development of health monitoring technology of plate structure is of great significance to modern industry.Ultrasonic SH wave-based damage detection technology has many advantages such as simple sensor structure,high system energy efficiency ratio,efficient signal data processing and analysis,and sensitivity to micro-damages.It can support long-term real-time for large plate structure Health monitoring.This paper focuses on the two key points of ultrasonic SH wave excitation-reception methods and damage detection methods.In turn,through theoretical derivation,numerical simulation analysis and experimental verification,an application study of ultrasonic SH wave-based plate structure damage detection is carried out:?1?Firstly,the propagation characteristics of ultrasonic SH waves in a free plate were studied through theoretical derivation,and the dispersion curve of SH waves in aluminum plates was drawn with MATLAB software to verify the non-dispersion characteristics of the basic mode SH waves.Methods of damage location,damage area identification and damage depth evaluation based on ultrasonic guided waves are introduced.?2?Then the principle and structure of d₁₅5 omnidirectional SH wave piezoelectric transducer were studied.The finite element software ANSYS was used to verify the performance of omnidirectional excitation and reception of SH waves,and through the numerical simulation analysis,the structural parameters of the transducer suitable for damage detection of the flat plate structure were determined.?3?Finally,an experimental platform for damage identification based on ultrasonic SH waves was built,and the experimental results were used to verify the recognition effect of SH waves on three different damages such as surface defects,circular through holes and corrosion in aluminum plates,and successfully achieved the The location and quantitative evaluation of through holes and corrosion damage are expected to further promote the development of large-scale flat structure damage detection technology based on ultrasonic SH waves.