Study on complicated nonlinear phenomena in ultrasonic infrared thermography using circuit simulation method

It has been shown that the complicated nonlinear vibration phenomena in mechanical workpieces under excitations of intense ultrasonic pulses increase greatly the detectability of defects (cracks). To study the nonlinear vibration phenomena of plates induced by the ultrasonic pulses, an electrical circuit model is proposed to simulate the mechanical vibro-impact motions between the transducer horn and plate sample based on the similar principles between electrical circuit systems and mechanical vibration systems. In the electronic circuit simulations of the nonlinear vibrations of plates, the analyses of the waveforms and frequency spectra are performed, which show that the harmonic, sub-harmonic, quasi-sub-harmonic and chaotic phenomena appear in the circuit model. The simulation calculation and data collection are simple and fast owing to algorithm of the Simulink. Therefore, the circuit simulation technique provides a useful approach to study and optimize ultrasonic infrared thermography for applying to NDE/T.