M.Ing. (Mechanical Engineering) / The use of longitudinally welded tube are limited in certain sectors of industry due to the belief that seamless tubes are superior. The main objective of this study was to try and prove that sufficient resistance to internal pressure could be achieved by longitudinally welded type 304L stainless steel tubes, while subjected to various external forces. A knowledge of plasticity theory and failure criteria provides the basis of the different mechanisms of tube failure. Four different tests were performed using different external forces, while internal pressure was increased until failure occurred. It was found that test specimens failed after reaching acceptable pressures, irrespective of the external loading conditions.

Abstract not available

"1st February 2002" / Includes bibliographical references (leaves 265-273) / xi, 273 leaves : ill. (some col.), plates (col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Concerns the specialized requirements of welding procedures used on operational gas pipelines. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 2004?

No description available.

Copies of author's previously published articles inserted. / Bibliography: leaves 254-264. / xx, 297, [26] leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the effects of various weld geometry parameters, residual stresses and the combined axial and bending loadings on the fatigue behaviour of butt-welded steel joints. Presents ways of improving the fatigue strength. Simulates the effect of the induced surface compressive residual stresses on the welded joints (for the improvement of the fatigue life). Explains the phenomenon of large scatter band associated with fatigue tests results. Suggests a new procedure for performing and evaluating the fatigue tests. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1996

Copies of author's previously published articles inserted. / Bibliography: leaves 254-264. / xx, 297, [26] leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the effects of various weld geometry parameters, residual stresses and the combined axial and bending loadings on the fatigue behaviour of butt-welded steel joints. Presents ways of improving the fatigue strength. Simulates the effect of the induced surface compressive residual stresses on the welded joints (for the improvement of the fatigue life). Explains the phenomenon of large scatter band associated with fatigue tests results. Suggests a new procedure for performing and evaluating the fatigue tests. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1996

Fracture path transition, from interfacial fracture to a pulled button, in peel tests of spot welds in SAE 1039 steel was evaluated to determine the controlling material properties. Welds were tested in the as welded condition and after tempering at various temperatures to develop a range of hardness and strength in the weld metal. Two transitions were found, from complete interfacial fracture to partial interfacial and from partial interfacial fracture to a pulled button. Samples tempered at less than 350 °C exhibited complete interfacial fracture while those tempered at 500 °C or higher pulled full buttons. Each transition was accompanied by a large increase in the energy absorbed during fracture. Both partial and complete interfacial fracture occurred by intergranular fracture along prior austenite grain boundaries. Optical microscopy utilizing a tint etch indicated that austenite existed as films on prior austenite grain boundaries of samples tempered at less than 500 °C and TEM confirmed that these films were austenite. Weld metal toughness was found to control the fracture path. If fracture initiation was delayed until the applied load caused plastic deformation of the coupons pulled button fracture occurred. Fracture initiation prior to plastic deformation of the coupons resulted in interfacial or partial interfacial fractures. A small secondary hardening peak was observed in samples tempered at 450 °C. Secondary hardening, which normally results from alloy carbide precipitation, was due to AlN precipitation in this aluminum killed plain carbon steel. / Ph. D.

To better understand the behavior of composite beams in buildings, push-out tests were conducted to study the behavior of welded shear studs. Forty-eight solid slab push-out tests were conducted to study how stud tensile strength and concrete properties affect the strength of shear connections. It is shown that raising the tensile strength of a shear connector actually has an adverse effect on the connector's performance and strength. It is also shown that the upper limit for shear strength used in the current AISC specification (Load 1993) is unconservative and a lower upper limit is proposed. Eighty-seven pushout tests utilizing steel deck were also conducted. It is shown how the placement, height, and arrangement of shear studs, as well as the height and gage of steel deck affects the strength of shear connections when stiffened steel deck is used. It is shown that the current AISC specification is unconservative and does not account for the many failure mechanisms associated with connections using steel deck. It is shown how tension within the stud shank, friction at the slab/beam interface, and steel deck strength affect the strength of shear connections. / Master of Science

This research evaluated the ethics competencies which were determined to be important to the curriculum of an ethics course for students studying Nondestructive Testing and Welding Inspection. Data were gathered from samples of American Society of Nondestructive Testing Nationally Certified Level III's (N = 268), American Welding Society Nationally Certified Welding Inspectors CWI's (N = 212) and American Welding Society Nationally Certified Associate Welding Inspectors - CAWI's (N = 101) who are currently licensed by their respective societies. The twenty-nine (29) item instrument utilized a six-point Likert type scale for the data collection. The scale, which was validated by consensus using a DELPHI panel procedure, utilized the Hoyt-Stunkard method for assessing reliability. The computed reliability for the instrument was determined to be +0.970. Analysis of variance tests were completed for each of the twenty-nine (29) competencies to ascertain differences between ASNT Level III's, AWS CWI's and AWS CAWI's samples. Factor analysis, using the R-mode, provided for the clustering of competencies and constituted the major analysis procedure for the study. The results of the study indicated the presence of three (3) clusters of content which were considered necessary to curriculum inclusion in an ethics course for nondestructive testing and welding inspection. The identified clusters include: I. Ethical issues and personal integrity (18 competencies), II. Ethics and the legal aspects of inspection (8 competencies), and III. Ethical theory and professional conduct (4 competencies). Overall competency means ranged from 3.929 to 5.594; significance tests showed only five (5) rejected hypotheses for the twent-ynine (29) primary competencies. Standard errors of the mean were found to be lower for the ASNT Level III's sample. The results of the study present a valid pattern for the development of objectives which should be included in an ethics curriculum for nondestructive testing personnel and welding inspectors. / Graduation date: 1993

The effects of hydrogen on the fracture behavior of manual SMA welds in carbon steel plate was investigated utilizing modified ½T compact tension specimens. Tests performed on these specimens in the presence of hydrogen were compared to similar tests in helium. These tests showed that hydrogen lowers J_C in both the heat affected zone and the base metal. In 350 psi helium, the experimental value of J_C in the heat affected zone (2826 in.-lbs./in.²) was greater than that obtained in the base metal (1650 in.-lbs./in.²). The tests conducted in 350 psi hydrogen resulted in a reduction in J_C for both the heat affected zone (1425 in.-lbs./in.²) and the base metal (59 in.-lbs./in.²). Furthermore, when compared to specimens tested in helium, it was determined that the material tearing modulus for specimens tested in hydrogen was significantly reduced. Slow stable crack growth occurred in all helium tests and in tests performed on the heat affected zone in hydrogen. However, unstable crack growth (fast fracture) was obtained for base metal tests in hydrogen. Fractographic studies revealed that the mechanism for all slow stable crack growth was microvoid coalescence; whereas, the surface of base metal specimens tested in hydrogen showed that fast fracture occurred by cleavage. Optical microscopy revealed that the fracture path for all base metal tests remained in the base metal, but that the fracture path for all heat affected zone tests moved towards the base. These observations, in conjunction with microhardness readings and quantitative metallography, were used to develop explanations for the observed behavior. These explanations include the combined effects of hydrogen, weld defects, residual stresses, grain size, and test variables such as temperature and specimen size and geometry. / M. S.