Detection of micro-crack in the early stages of damage is crucial to understanding the mechanical properties of materials and structures,and enabling timely remedial action.However,existing defect imaging methods struggle to detect micro-crack smaller than a millimeter.Based on the mechanism of ultrasonic nonlinear effect induced by micro-crack,this paper demonstrated,through numerical simulations,that nonlinear ultrasonic phased array total focusing method imaging technology can detect micro-crack below a millimeter level.The results showed that,firstly,the interac-tion between ultrasound and micro-crack caused the breathing effect that induced nonlinear ultrasound,allowed phased array elements to receive the second harmonic signal.Secondly,the second harmonic signal in nonlinear phased array im-aging followed the superposition principle.Finally,nonlinear ultrasonic phased array imaging technology successfully achieved imaging of micro-crack below a millimeter level.These findings are significant in clarifying the mechanism of micro-crack in nonlinear phased array imaging,and they provide a new foundation for theoretical research in nonlinear phased array imaging.
维普
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