INTRODUCTION <br>1.1 Research Background <br>1.2 Objectives and Scope <br>1.3 Contributions and Originality <br>1.4 Organization <br>LITERATURE REVIEW <br>2.1 High Strength Steel (HSS) <br>2.1.1 Overview <br>2.1.2 Delivery Condition of HSS <br>2.1.3 Fatigue and Fracture of HSS <br>2.1.4 Codes and Standards of HSS application <br>2.2 Welding and Residual Stress <br>2.2.1 Overview of Arc-Welding <br>2.2.2 Weldability of Steel <br>2.2.3 Phase Transformation and Other Phenomenon in Welding Procedure <br>2.2.4 The Formation of Residual Stress <br>2.2.5 Residual Stress Investigation Techniques <br>2.2.6 Exploration on Residual Stress Effects <br>2.3 Fatigue Analysis of Tubular Joints <br>2.3.1 Classification and Parameters of Tubular Joints <br>2.3.2 Stress Analysis of Intact Tubular Joint <br>EXPERIMENTAL INVESTIGATION OF RESIDUAL STRESS FOR HIGH STRENGTH STEEL PLATE-TO-PLATE JOINTS <br>3.1 Introduction <br>3.2 The Hole-Drilling Method and Specimen Details <br>3.2.1 The ASTM hole-drilling method <br>3.2.2 Specimen Specifications <br>3.2.3 Welding Specification <br>3.3 Residual Stress Investigation <br>3.3.1 Setup and Modification of the Hole-Drilling Guide <br>3.3.2 Strain Gauge Locations <br>3.3.3 Calibration Test for Residual Stress Measurement <br>3.3.4 Residual Stress Measurement Procedure <br>3.3.5 Cutting of Brace Plate <br>3.4 Experimental Results <br>3.4.1 Distribution of Residual Stress Along the Weld Toe <br>3.4.2 The Effects of Preheating <br>3.4.3 The Effects of Joint Angle <br>3.4.4 The Effects of Plate Thickness <br>3.4.5 The Effects of Brace Plate Cutting <br>3.5 Static Tensile Testing <br>3.5.1 Testing Rig <br>3.5.2 Strain Gauge Locations <br>3.5.3 Testing Procedure <br>3.5.4 Testing Results <br>3.6 The Influence of Residual Stress on SCF Value <br>3.6.1 Analysis method <br>3.6.2 Results and Conclusions <br>3.7 Conclusion and Summary <br>NUMERICAL STUDY OF RESIDUAL STRESS FOR HIGH STRENGTH STEEL PLATE-TO-PLATE JOINTS <br>4.1 Introduction <br>4.2 Modelling Procedure and Results For 2d Models <br>4.2.1 Overview <br>4.2.2 The Lumped Technique <br>4.2.3 Weld Filler Addition Technique <br>4.2.4 Heat Transfer Analysis <br>4.2.5 Mechanical Analysis <br>4.2.6 Model Validation and Results <br>4.3 MODELLING PROCEDURE AND RESULTS FOR 3D MODELS <br>4.3.1 Overview <br>4.3.2 Heat Source <br>4.3.3 Modeling for the Weld Filler Adding Process <br>4.3.4 Modeling Validation <br>4.3.5 Modeling Results <br>4.4 PARAMETRIC STUDY <br>4.4.1 Effect of Boundary Condition <br>4.4.2 Effect of Preheating Temperature <br>4.4.3 Effect of Using Different Lumps <br>4.4.4 Effect of Welding Speed <br>4.4.5 Effect of Welding Sequence <br>4.5 Conclusions <br>EXPERIMENTAL INVESTIGATION OF RESIDUAL STRESS FOR WELDED BOX HIGH STRENGTH STEEL T JOINTS <br>5.1 Introduction <br>5.2 Experimental Investigation <br>5.2.1 Material Properties <br>5.2.2 Specimen Fabrication <br>5.2.3 Test Setup and Procedure <br>5.2.4 Strain Gauge Schemes for Residual Stress Measurement <br>5.2.5 Computation of Residual Stress <br>5.3 Testing Results <br>5.3.1 Preheating Specimen <br>5.3.2 Ambient Temperature Specimen <br>5.4 Analyses and Discussion <br>5.4.1 Preheating Effect <br>5.4.2 Chord Edge Effect <br>5.4.3 Corner Effect <br>5.4.4 Stress Variation in Depths <br>5.5 Conclusions <br>NUMERICAL STUDY OF RESIDUAL STRESS FOR WELDED HIGH STRENGTH STEEL BOX T/Y JOINTS <br>6.1 Introduction <br>6.2 Modeling Procedure <br>6.2.1 Overview <br>6.2.2 Heat Source Model <br>6.2.3 Thermal Interactions <br>6.2.4 Arc Touch Moving <br>6.2.5 Modeling Summary <br>6.3 Modeling of Pure Heat Transfer <br>6.4 Fully Coupled Residual Stress Analysis <br>6.4.1 Modeling Validation <br>6.4.2 Modeling Results <br>6.5 Parametric Study <br>6.5.1 Range of The Modeling <br>6.5.2 Variation of The Residual Stress with Respect to Joint Angle <br>6.5.3 Variation of The Residual Stress with Respect To B/C (Ratio of Brace Width to Chord Width) <br>6.5.4 Variation of The Res