基于稀土换能器的混凝土厚度检测技术研究

基于稀土换能器的混凝土厚度检测技术研究
　　It’s always difficult to measure the thickness of the large volume concrete in the bridge test. At present, there are some methods to test the thickness of the concrete, such as digging a pit, drilling a hole and sampling, testing the echo of the shock wave, detecting the terra radar and reflecting the ultrasonic. The first and the second methods belong to the damaged test, and the others are undamaged test. These methods are mainly used to test the thickness of the road concrete, but can’t be used to test the thickness of the large volume concrete, because the low power and the long aftershock of the energy exchanging instrument used in the test.This paper analyses the different characters of the vertical wave, the transverse wave and the surface wave, summarize the spreading rule of the ultrasonic with different incidence. It also summarizes the advantages of these testing methods of ultrasonic. We Ring neodymium magnet tested the thickness of the concrete both in the laboratory and the bridge using the rare-earth and over-magnetism energy exchanging instrument. The result indicates that the rare-earth energy exchanging instrument our developed has the character of high power and short aftershock. It is fit for the thickness test of the large volume concrete.Aiming at the question of start reflecting point determination, by analyzing the different spreading path and the speed of the transverse wave, vertical wave and the reflecting vertical wave in the ultrasonic , a slope distinguish method is put forward to resolve this difficulty.Besides, aiming at the sensitivity to the frequency break in the small wave http://www.chinamagnets.biz/ analytical method, the shape of the reflecting wave is analyzed. Through choosing the appropriate basic small wave function and the appropriate scale and time-shift gene, and using the opposite character of the max small wave coefficient and the starting point of the instantaneous wave, it can test the arriving time of the echo in the concrete bottom.Ring neodymium magnet  Therefore, the paper solves the problem of the thickness test in the large volume concrete using diversified data dealing method and the rare-earth and over-magnetism energy exchanging instrument which has broad band. It can provides the reliable ultrasonic data and thickness data for the bridge undamaged test and its health test. It also applies for the large volume concrete test in the tunnel and the large dam, and has important meaning in improving the test level of the large volume concrete in our country. 更多还原