Ultrasonic waves have the following characteristics:
1. Ultrasonic waves can effectively propagate in media such as gases, liquids, solids, and solid melts;
2. Ultrasonic waves can transmit strong energy:
3. Ultrasonic waves can cause reflection, interference, superposition, and resonance phenomena; When ultrasound propagates in liquid media, it can generate strong impact and cavitation phenomena at the interface. Ultrasonic waves propagating in solids are also known as ultrasonic guided waves. Ultrasonic guided waves have shorter wavelengths than general sound waves, better directionality, and can pass through opaque materials. This characteristic has been widely used in ultrasonic flaw detection, thickness measurement, distance measurement, remote control, and ultrasonic imaging technology
Due to its long history of development, mature technology, simple operation, convenient feedback signal processing, strong penetration power, and ability to accurately detect and locate macroscopic defects such as micropores and microcracks in materials, ultrasonic testing has been increasingly widely used.
Ultrasonic nonlinear detection is a new detection method based on the elastic dynamics theory of material constitutive relationship nonlinearity. It is based on the research that the manifestation of material degradation is the nonlinearity of material constitutive relationship. Ultrasonic nonlinear analysis, as a non-destructive testing technique, is mainly used for risk assessment of microcracks, weak bonding, and fatigue strength in materials, which is different from conventional ultrasonic nonlinear analysis and harmonic measurement of nonlinear coefficients.
