Modeling of residual stress in thick section weldments
Welding processes produce residual stresses and distortion as a result of the large nonlinear thermal loading created by the arc. Cracking and lamellar tearing have been experienced just after welding and later during the intended service life. Particularly, tensile residual stresses in regions near the weld may cause brittle fracture, fatigue or stress corrosion cracking. Thus, accurate prediction of magnitude and distribution of residual stresses near welded joints is a paramount importance. This represents an engineering approach to predict and control the welding stresses in multipass thick-section weldments. An uncoupled, nonlinear, thermo-mechanical finite element model was developed for analyzing thermal related welding problems. To reduce the computational and data storage requirements, a two-dimensional finite element model was developed and compared to the three-dimensional model. Experimental measurement of surface residual stress by blind hole drilling method verified the numerical results. Model simplifications were justified by the physical phenomena observed during welding. Ramp heat input functions and lumped weld passes were employed for finite element analysis. Ramp heat input functions were used to simulate the actual heat input of the moving arc and improve the numerical convergence of the thermal model. A lumped pass model which combines multiple weld passes was developed to reduce the computational time. The generalized plane strain elements of ABAQUS finite element codes were used for residual stress calculations. Parametric studies on the other modeling parameters; mesh type and size, model symmetry, heat input mode, and welding process, were also conducted to develop guidance for the optimum modeling procedures in these engineering applications. To further validate and refine the modeling techniques, experimental and analytical studies were conducted for 1-inch and 2-inch thick butt welded plates.
- Research Organization:
- The Ohio State Univ., Columbus, OH (United States)
- OSTI ID:
- 7168071
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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