Nondestructive Evaluation of Solids Based on Deformation Wave Theory

Abstract

The application of a recent field theory of deformation and fracture to nondestructive testing (NDT) is discussed. Based on the principle known as the symmetry of physical laws, the present field theory formulates all stages of deformation including the fracturing stage on the same theoretical basis. The formalism derives wave equations that govern the spatiotemporal characteristics of the differential displacement field of solids under deformation. The evolution from the elastic to the plastic stage of deformation is characterized by a transition from longitudinal (compression) wave to decaying longitudinal/transverse wave characteristics. The evolution from the plastic to the fracturing stage is characterized by transition from continuous wave to solitary wave characteristics. Further, the evolution from the pre-fracturing to the final fracturing stage is characterized by transition from the traveling solitary wave to stationary solitary wave characteristics. In accordance with these transitions, the criterion for deformation stage is defined as specific spatiotemporal characteristics of the differential displacement field. The optical interferometric technique, known as Electronic Speckle-Pattern Interferometry (ESPI), is discussed as an experimental tool to visualize those wave characteristics and the associated deformation-stage criteria. The wave equations are numerically solved for the elastoplastic stages, and the resultant spatiotemporal behavior of the differential displacement field is compared with the experimental results obtained by ESPI. Agreement between the experimental and numerical results validates the present methodology at least for the elastoplastic stages. The solitary wave characteristics in the fracturing stages is discussed based on the experimental results and dislocation theory.

Retracted: Design and Performance Evaluation of OAM-Antennas: A Comparative Review

“…After that, reference [3] were experimentally verified. References [4][5] proposed and developed concepts such as phase dislocation, phase singularity, and vortex beam, and then conducted further research [6][7][8][9][10], gradually enriching the theory, generation, and related properties of vortex light. Reference [11] found that the vortex laser beam formed by Laguerre-Gauss (LG) beams had orbital angular momentum, and clearly determined the relationship between orbital angular momentum and vortex topological charge the relationship between.…”

Dynamic ESPI Evaluation of Deformation and Fracture Mechanism of 7075 Aluminum Alloy

“…The deformation behaviors of Al–Zn–Mg–Cu alloys were measured with the two-dimensional ESPI described in the previous work [ 9 ]. The experimental set-up is shown in Figure 1 .…”

“…Yoshida et al [ 8 ] discusses the specific wave types that differentiate stages of deformation in association with the corresponding optical interferometric fringe patterns. In [ 9 ], Yoshida et al extend the discussion to the transition to the fracture and identify the shear band as manifestation of the solitary wave dynamics in association with micro-fracture and corresponding dislocation dynamics.…”