The Application Of Time-frequency Methods In Concrete Flaws Determine

To enhance the supervision and control of concrete is becoming a significant task. As a precondition not to influence the capability to load or other function. The examine means to menstruate some relevant physical value right on the framework or component. that is, nondestructive evaluation become an important direction of civil engineering. But at present, most of the means of nondestructive evaluation can only determine the existence of flaws, or approximately estimate the size, location of flaws by experience, as s stage of qualitative analysis of flaws, the results from these means are unsatisfactory. So a lot of quantitative study ways to determine the flaws have significant practicable value and applicable prospect.In this paper, the basic theory of the ultrasonic nondestructive is discussed. The means of nondestructive evaluation are also been discussed. The main researches are listed as follows:1. The basic theory of the ultrasonic nondestructive is discussed. Some things affect the means of the ultrasonic nondestructive are discussed.2. The research and application status of spectral imaging home and abroad are introduced; the present widely used spectral imaging methods are summarized, such as STFT, CWT, S transform, and Cohen class time-frequency distribution, etc.; the methods above are compared and analyzed by model signals and their merits and demerits are summarized.3. The model is been discussed, a lot of the time-frequency methods are used to determined the flaws.4. The real singles are been analyzed by the time-frequency methods.