Welded high strength steel structures : welding effects and fatigue performance / Jin Jiang.

Place of publication from CIP data view.

Includes bibliographical references and index.

"In this book, an investigation on the residual stress distributions high strength steel (HSS) welded joints is carried out. Two groups of specimens, corresponding to welding preformed at ambient temperature and at a preheating temperature of 100℗ʻC, are fabricated. The effects of preheating and joint geometry on the residual stress distribution near the weld toe are investigated by applying the standard ASTM hole-drilling method for residual stress measurement. A preliminary study is also performed to evaluate the influence of brace plate cutting on the residual stress distribution near the weld toe of the joints. A carefully sequentially coupled thermal-mechanical modelling procedure is developed for residual stress analysis for the HSS plate-to-plate joints. Both 2D and 3D models were created to investigate the residual stress distribution in the HSS joints. A small-scale parametric study is carried out to investigate the influence of some key welding parameters such as the boundary condition, the preheating temperature, the number of welding pass, the welding speed and the welding sequence on the magnitude and distribution of residual stress. It is found that while transverse residual stress with magnitude as high as one third of the yield strength of HSS could appear near the weld toe of the joint, proper preheating could significantly reduce the magnitude of the residual stress. Besides the investigation for the residual stress in the HSS plate-to-plate T and Y-joints, the study for welding residual stress in box HSS T-joints is also included. Two box HSS T-joints with the same geometrical size were fabricated to investigate the welding residual stress distributions of HSS box joints. One specimen is welded at ambient temperature while the other one is preheated to 100℗ʻC before the welding. It is found that the residual stress at chord weld toe along the surfaces parallel to chord length are generally smaller than along the surfaces perpendicular with chord length. Fully thermal-mechanical coupled analysis is used in the modeling for the residual stress distribution in box HSS joints. In order to reduce the computational cost, only the chord-brace intersection is selected for analysis. Two models corresponding to the specimens (100℗ʻC preheating, welded at ambient temperature) are created and validated by testing results. After that, parametric studies were carried out to investigate the impact of welding parameters such as preheating temperature, weld speeding and geometrical parameters such as joint skewed angle and ratio of brace width to chord width on the residual stress distribution. It is found that the preheating treatment can reduce the magnitude of the principle residual stress at the weld toe. When the ratio of the brace width to the chord width is larger enough, the transverse residual stress between two welds can be reduced due to superposition. In addition, the welding speed has significant influence on the magnitude of residual stress at the weld toe. Higher speed can effectively relieve the residual stress at the weld toe"-- Provided by publisher.

About the Author
Jin Jiang, PhD, is Professor in Department of Civil and Environmental Engineering, Shantou University, China, Senior Researcher of Civil Engineering at Nanyang Technological University, Singapore and Associate Director of the Complex Steel Structure Research Center, Guangdong Province, China. He is also a technical assessor with the Singapore Accreditation Council (SAC) and a member of the American Society of Civil Engineers (ASCE), and has previously served as a researcher engineer at the Keppel Offshore and Marine Technology Center.

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