Ultrasonic Ct Numerical Simulation And Experimental Research

This mastership dissertation aims at CT technique of ultrasonic for concrete non-destructive test. On the one hand, an extension & compaction algorism is adopted and sub-resources are logged. Numerical simulations and experiments show that improved algorism of LTI is effective to trace rays including back waves and suitable for computerized tomography to complex object. Compared with straight ray tracing, inversion of bending ray tracing is better when data of test are accurate. On the other hand, natural weight is introduced and numerical simulations and experiments of WLM on inversion of velocity and attenuation are also made, which show that WLM, with resistance of noises and convergence of iteration, may get good re-construction images. And effects on improving original inversion image are clear by associated use of post treatments, variance truncating, median filtering and classification analysis. Furthermore, numerical simulations and experiments of inversion of velocity and attenuation are made. Results indicate that inversion of ultrasonic can reflect the position, size and property of defects right. In addition, concrete inner defects are identified based on two different physical parameter, velocity and attenuation, which will greatly increase precision and reliability.In conclusion, the developed CT technique of ultrasonic for concrete non-destructive test is of great significance in both theory and practice.