Method and apparatus for nondestructive testing of the mechanical behavior of objects under loading utilizing wave theory of plastic deformation

摘要

PCT No. PCT/JP93/01424 Sec. 371 Date May 31, 1994 Sec. 102(e) Date May 31, 1994 PCT Filed Oct. 5, 1993 PCT Pub. No. WO94/17362 PCT Pub. Date Aug. 4, 1994.A new method of nondestructive testing of mechanical behaviors of objects under loading has been invented based upon the analysis of spatial and temporal distributions of velocities of deformation and rotation under elastoplastic deformation. In order to carry out this method, optical images of the surface of an object under test are obtained as holograms of a focused image, and diffraction patterns of superimposed images are then formed for a number of consecutive time points spaced with short time intervals. These diffraction patterns are then transformed into wave patterns of space and time distributions of velocities of deformation and rotation along with the respective axes. These distributions are analyzed according to the wave theory of plasticity and strength developed by the present inventors. Wave lengths, amplitudes and velocities of relaxation waves of plastic deformation are determined, and dynamics of these parameters are used to predict the time and point of eventual failure.