Identyfikacja kruchych mikrouszkodzeń elementów betonowych za pomocą tomografii ultradźwiękowej

An application of ultrasonic transmission tomography to reconstructions of ultrasonic wave velocity distribution in cross-sections of structural members affected by brittle microdmageis presented in the paper. To simplify the problem the methods of continuous damage mechanics for modeling change of sonic wave velocity caused by damage of material is employed in the isotropic case. Also the concept of division of tomographically tested cross-sections into square “cells” of constant sound velocities and assuming straight “rays” of ultrasound propagation between the sending-receiving points are introduced in the considerations. Finally own numerical example is discussed for concrete prismatic element which shows a satisfactory precision of the used tomographic imaging if a local drop of sound velocity is not bigger than 20% in a comparis on with material in the undamaged state. The effect is related to neglecting in the considerations the diffraction of ultrasonic waves on the damage areas.