Study On Defects Detecting Of Mechanical Parts With Coating By Laser Ultrasonic Technology

It is a big problem to detect the defects of mechanical parts with coating.However there are problem existing such as low sensitivity and efficiency among traditional detecting means.Laser Ultrasound technology has a better controlling ability to have higher temporal and spatial resolution ratio because of it’s way to irritate ultrasound.All these give it a broad application prospect.Using the way connecting operating experiment and theory studies the feasibility and high efficiency of defects detecting of samples with coating.It has a deeper studying of the law of different waveform and frequency distribution of laser irritates ultrasound,of law of Time of flight to compute the sizes when detecting different sizes of length,width,depth..Then it analyzes why the error occurs when proceeding the shapes of defects and sizes evaluation,why coating could arise dispersion.,also proceeds coating parameters inverting which arise ultrasound disperses.Based on thermal-elasticity mechanism,it applied light interference apparatus detect the size of defects under the effects of coating.Creating two different models to explore depth detecting and analyzing the reason of error forming which is ultrasound diffraction and dis person arose by coating..Build a high precision reflection detecting system has a good way to detect depth of coating.It shows error doesn’t increase linearly with layers and depths increase linearly.Referring to neutral net algorithm,its aim is to invert the parameter of coating material finally.Applying laser-ultrasound system to detect manual defects,among the size detecting,the direction of length and width detecting errors is lower than 10%.For depth detecting example,the single layer detecting error is lower than 5%,the double layers lower than 10%.The parameter inversion error is lower than 2%.Using Laser Ultrasound technology can detect the shape and size of defects.According to detecting signal and algorithm results,it can deduce the property of coating.All these have laid a basis technology verification of our next steps studies to apply to coating lifetime evaluation and failure analysis study.