Papers by Author: Joseph L. Rose

Abstract: Presented in this paper is a numerical approach to extract useful features of SH guided wave scattering in a Plate-like structure with thickness variation. The problem statement is chosen to establish a physically based guideline for mode selection and data analyses in power industry application. The hybrid BEM technique with absorbing boundaries on the structure cross-sections is proposed to calculate reflection and transmission from thickness variation. Sample numerical data is presented as a function of incident mode, frequency and defect geometry. Mode optimization is proposed to enhance penetration power and quantify geometry change based on various interesting features including reverberation pattern of scattering fields.

Abstract: Rail represents one of the most important means of transportation. Many nondestructive testing methods have been used to find defects in rail. The guided wave technique is the most efficient because of its long propagation characteristic along the rail. The wave structure of the rail cross-section for a particular loading condition of modes and frequencies is an important feature. The wave structures are examined at different modes and frequencies. The propagation scattering patterns of guided waves from various multiple defects in a rail are also studied using finite element method.

Abstract: Rail represents one of the most important means of transportation. Many nondestructive testing methods have been used to find defects in rail. The guided wave technique is the most efficient because of its long propagation characteristic along the rail. Potential for detecting transverse cracks exists whereas standard bulk wave technique could miss the cracks. The wave structure of the rail cross-section for a particular loading condition of modes and frequencies is an important feature. In this paper, the propagation and scattering patterns of guided waves in a rail are studied using finite element methods. The wave structures are also examined. Various multiple defect situations and rail boundary conditions can also be studied.