Boy Raymond Mabuza

Vaal University of Technology | vut · Department of Physics and Non-Destructive Testing

This paper provides a study on mixed-mode fracture mechanics in thin-walled tube which is subjected to tension, shear and torsion loading. This type of loading causes an inclined crack to develop and generate a mixture of normal and shear stresses ahead of a crack tip. The stress state ahead of a crack tip is frequently based on mixed-mode type of...

In this paper, the focus of attention is on the effect of an elastic middle layer on the propagation behavior of ultrasonic waves. Systematic parametric studies are conducted to quantify the effects of the middle layer upon the ultrasonic wave propagation, including its thickness and acoustic impedance. We treat this problem analytically and numeri...

This paper describes an investigation into the possibility of using non-contact ultrasonic transducers for detecting and characterizing defects in aerostructures. Our study deals with an ultrasonic method that underscores the recent advances in non-contact and analytical methodologies. Ultrasonic waves are generated by a transducer connected to a S...

This paper presents the capability and necessity of ultrasonic testing methods for studying fracture mechanics problems taking into account the flaws in steel plates. The computational simulation of flaw propagation for the flaws is based on a numerical integration of Paris equation. The theoretical and experimental results for both fracture mechan...

This paper discusses the capability and reliability of surface waves in terms of detecting and characterizing surface defects. A good understanding of which defect characteristics affect detection and characterization is essential when using ultrasonic testing method. According to Rayleigh, surface waves propagate along the solid surface and their...

In this paper we focus our attention on the Marchenko inversion method which requires as input the reflectivity sequence of the medium with the view to reconstructing the seismic impedance from seismic reflection data. The reflectivity sequence and the relevant seismic wavelet are extracted from marine reflection data by applying the statistical es...

The effect of antisymmetrization in diquark models of baryons composed of light (u&d) quarks is investigated. The diquark in this study is considered alternately as a point-like and as a composite particle where antisymmetrization is taken into account by means of Generator Coordinate Model operator kernels. The effect on ground state masses and fo...

The world of today is experiencing a new revolution triggered by the onset of advanced composite materials. Due to the increasing use of honeycomb structures in aerospace, aviation and marine industries, delamination is of great concern. The highly effective signal transmission of a DryScan 410D (shadow technique) makes it possible to characterize...

Couplants are essential for providing the necessary link between transducers and materials in ultrasonic testing. In this paper, various couplants are used on aluminium and carbon steel materials to study the effects they have on the amplitudes of back wall echoes. The amplitudes of back wall echoes increase with increasing acoustic impedance of co...

The probability theory has found its major application in many engineering and industrial areas for the detection of defects inside structures. It can be used to assess the risks involved in the decision-making process. Probabilistic methods provide essential tools used in the better assessment of the impact of uncertainties on component life and r...

The study is a preliminary effort which investigates the effect of variations of crack geometry on the stress concentration factor on a simple thin plate subjected to a constant, uniform, uni-axial tensile load. The geometry of the central crack is varied to produce rectangular models ranging from circular, elliptical to sharp cracks. Due to symmet...