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Three dimensional (3D) image-based FIT has been proposed to predict ultrasonic wave in a target material with complex outer surfaces or various inclusions. In this study, we accelerate the 3D image-based FIT by means of some explicit parallelization techniques. By adopting flat MPI and MPI I/O techniques, our programming code can execute with a high speed and show good scalabilities in large size problems. Here we introduce a new image-based modeling that the target model can be made with a 3D curve measurement apparatus based on the light pattern projection method. The surface irregularities of the corroded part in a steel plate can be precisely modeled and the ultrasonic wave simulation for the corroded steel plate is demonstrated. [ABSTRACT FROM AUTHOR]

Time domain simulation tools for ultrasonic wave propagation in a target material with a complex outer surface or various inclusions are developed by combining the finite integration technique (FIT) and the finite element method (FEM) with an image-based modeling. In our simulation, the geometry of the target is determined by a digital image such as X-ray picture, CAD data, etc. and the processed voxel data is directly fed into the numerical calculation with the FIT or FEM. The accuracy of the two methods is discussed by comparison with the boundary element method. A simulation of the ultrasonic testing for a concrete material is shown with the 3-D image-based FIT. [ABSTRACT FROM AUTHOR]

A finite difference time domain method (FDTD) is based on a grid-based time domain differential technique, in which wave equations are solved in a leapfrog manner. It is required to discretize a whole target domain into computational grids with an adequate size. Therefore computational burden increases if the computational domain is much larger than the wave length. To solve such a large-scale problem in high speed, we apply a parallel computing technique to the FDTD. OpenMP is an interface to execute program codes in parallel using a shared memory system of computers. As an example of large-scale analysis, SH wave propagations in concrete material are demonstrated in this study. [ABSTRACT FROM AUTHOR]

A numerical modeling of an interface including a local imperfection and simulation of the ultrasonic wave propagation through the interface are described in this paper. We propose an imperfection model with the interface condition depending on displacement-stress states. This phenomenon generates superharmonics in the transmitted wave through the interface. The interface model is incorporated into a time domain boundary element method and transmitted waveforms are calculated. Simulation results show that the amplitude ratio of superharmonic waves changes according to the initial opening gap and the length of the imperfection area. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

A high-speed analysis of three-dimensional linearized inverse scattering method is proposed for real time imaging of flaws. The principal operation of the linearized inverse method is the integration of the scattering amplitude in the K-space. In this study, the three-dimensional fast Fourier transform is introduced into the inversion algorithm to evaluate the integral in the K-space. From the results of numerical investigations, it is shown that the computational time of the inversion is reduced without the loss of the image quality for the shape reconstruction. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A shape reconstruction method in an inhomogeneous material is investigated by using the ultrasonic waveforms in this study. The frequency characteristics of phase velocity due to inhomogeneity of the material are introduced to the Born and Kirchhoff inversion algorithms. Here, the mortar specimens containing volume fractions of 5% and 10% inclusions are prepared. The results show that the Born and Kirchhoff inversions reconstruct the shape and size of the artificial defect in mortar specimens. [ABSTRACT FROM AUTHOR]