The Development Of Measurement Device For Ultrasonic Visualization Based On The Dynamic Photoelastic Method

As ultrasonic has a strong penetrating power, without ionizing radiation, harmless tohuman body, therefore, in nondestructive testing technology, the ultrasonic detectingtechnology is an important method. However, ultrasonic is a stress wave which we can’tobserve directly. When people study ultrasonic wave propagation and scattering inmaterial, they can only through the ultrasonic transducer that receives sound waves in thematerial surface. In this way they obtain the local information, whereas the internal rulethat spread of sound waves in material requires inference. In order to better understandingand the study of acoustic field, it is necessary to realize visualization of sound wavetransmission, let the invisible sound field to be visually displayed in the form of image.In this paper we study the principle of dynamic photoelastic method and mechanismof stroboscopic, through constructing experimental platform verify the feasibility of thescheme, provides a good method for investigate the scattering of ultrasound in solidresearch. The concrete research methods and achievements are as follows:First of all, through discussing the principle of photoelastic method and mechanismof stroboscopic measurement, made the plan of stroboscopic measuring device, andproved the feasibility of solution.Then, using the FPGA platform for writing the specific delay time program, hasrealized the regulation of the pulse signal, pulse width, time delay and time control,implements the system demands about the narrow pulse width of pulsesignals.Then,simulation is conducted using modelsim software. Made a reasonable PCB,chose the appropriate chip as a driver, and implement the pulse signal of the signalamplification. Through discussion on characteristics of led, chose the right led as a lightsource.Lastly, based on the frequency flash elastic measuring device, has reached desiredexperiment effect in different glass sample made experiments and has made the analysisfor the experiment results.