The Study On The Measure Of Void Content In Composite Materials And Its Implement

Under background of the correlative project, this dissertation researches on the measure of void content in carbon-fibre composites and designs a portable ultrasonic testing system of composites material. Firstly, the dissertation concludes the formula of void content. And then, demarcates the formula coefficients by the experimental data. Finally, based on introduction of the functions and structure of the system, this dissertation is mainly to discuss and study the technologies of sampling and processing data in the system. The six chapters of the essay are as follows.In chapter one, which is the preface of this dissertation, introduces and prospects the technologies of nondestruct testing in composites material according to the statement of the background and the requirement of this project at first. Then, mainly discusses the technologies of measuring void content in carbon-fibre composites, gathering and processing data. Finally, offers the general framework of the dissertation.In chapter two, firstly introduces actuality of measuring void content composites material. Afterwards, analyses the several former methods of measuring void content and pays emphases on discussing and concluding the method of formula modulus. Via analyzing and comparing rationality and feasibility of these methods, we choose the method of formula modulus as the measure of void content in the system.In chapter three, firstly introduces reason and reckoning method of ultrasonic attenuation. And then, by analysing the working theory of pulse echo and transmission, concludes the formula of ultrasonic attenuation coefficient in the methods of pulse echo and transmission, and determines the correlative coefficients. Later, tailors normal specimen and measures the void content by micrography. Finally, demarcates the coefficients of the void content formula in the method of formula modulus using the results in these examinations.In chapter four, firstly introduces the working principles and sort of ultrasonic testing and basal issues in ultrasonic testing. Then, on the base of them, designs the blueprint of the portable ultrasonic testing system and introduces the structure of it. Finally, discusses and studies the implement of the functions in sampling and transmiting data of the system emphatically.In chapter five, firstly analyses the necessary of storage and disposal the real time sampling data. Whereafter, studies the pivotal issues which includes thefoundation of real time sampling data files, the disposing of temporal undee ultrasonic signal, the analysing of histagram in the void content, the measuring of the void content in new materials. And designs the relevant software modules. Consequently, makes the system have these functions of the data processing and void content calculating and analyzing.In chapter six, summarizes the retrospections and conclusions of this dissertation. At the same time, gives the future work suggestion.