| Computational Weld Mechanics (CWM) methods and principles are employed to simulate the thermal and mechanical response of large welded structures with multiple pass welds. Special computational algorithms were developed to deal with the length scales that range from a fraction of a mm near the weld pool to the overall dimensions of the welded structure. Composite meshing and adaptive meshing were used in order to reduce the cost of computing inherent for a large structure analysis.;The transient equations for heat transfer, the stress and strain evolution and microstructure changes are all solved in a three dimensional (3D) domain. A prescribed temperature field model for the weld pool was used. Temperature dependent material properties are considered in the analysis, as well as filler metal addition. Different constitutive models are used to model the stress and strain fields for weld temperatures varying from room temperature to liquidus temperature.;A methodology to assist engineers in CWM analysis of large scale welded structures with complex geometry and multi-pass welds is presented.;The methods developed in this thesis are used to simulate welding on a pressurized natural gas pipeline and to determine if CWM can provide useful estimates of the risk of burn-through. Computed results agree well with the experimentally measured values. |
