Welding remains to be one of major manufacturing processes in the automotive industry. In addition to resistance welding, arc welding processes have recently received an increasing attention as some of the advanced designs of automotive structures are being introduced, such as hydro-formed frame structures. As such, it has become increasingly important that math-based design and manufacturing tools be developed to achieve concurrent design and welding process development in today's competitive environment. In this paper, some of the state of the art computational modeling techniques are first summarized. These modeling techniques can be used to establish welding procedure effects on weld quality, residual stresses, distortions, and more importantly, on structural integrity of the welded structures. The applications of some of the advanced analysis techniques are demonstrated by using a number of detailed case studies. The implication on optimum weld design and welding procedure development will be highlighted using specific examples.