Failure Model Based On The Material Of The Sound Image Defects

In modern days, many new kinds of materials have been widely used in many martial and electronic fields. Because of the material's complexity in processing or in using, there come many types of defects which may badly effect on its performance and age. It seems to be very important to build the defect model and the invalidation model of material, as it can help to realize its NDT (Nondestructive Testing) and keep a check on its quality and using state.As a new-type high-efficient NDT instrument, SLAM (Scanning Laser Acoustic Microscope) is a type of acoustic microscopy, and it is a very useful tool to study the internal structure of new materials or new devices. Using SLAM image system, we can not only get the amplitude image of the internal of the detected object, but also get its phase image. From the close relation among amplitude, phase and the material's parameters, we can obtain its according acoustic velocity image and attenuation image, by signal analyzing and image processing. After built the material's defect model in theory, combined the attenuation image and damage mechanics of acoustic, we can get the material's invalidation model.Chapter one introduces the background of development and status of application and the development on domestically and abroad. Chapter two tells of technology and theory which will be used in latter system design, such as SLAM system and digital image processing. Chapter three designs and modifies the SLAM image system, analyzes the relations between the acoustic signal and the material parameters. After processing the amplitude image and phase image which was come from experiment we obtain the distribution of the velocity and attenuation. Chapter four builds the defect model after analyzing the acoustic wave transmission, analyzes the relation of acoustic press and material's defect shape and size by computer's calculating and simulating. Chapter five obtains many defect models and analyzes the capability and longevity of multiplayer ceramics using the basic theory of damage mechanics and the result of chapter four. Chapter six summarizes the application development. It should be noted that the method that we can build the material's defect model and invalidation model by using the images which come from the SLAM system is innovative, and is never published on any article.