Restraint stress and strain in circular patch welds

Patch welding is mainly performed for repair, reinforcement and so on. In this study, the characteristics of the restraint stress and strain produced in circular patch welding and their production mechanism are elucidated from the results of the thermal elastic-plastic analysis. Then, the analytical calculation procedure of the restraint stress and strain produced by circular patch welding is shown based on the production mechanism of the restraint stress and strain. As the result, the formula to provide the restraint stress and strain is proposed. Moreover, the applicability of the restraint intensity as a mechanical measure for cold crack initiation in circular patch welding is investigated. Severity of the mechanical restraint condition in the elastic range can be evaluated by using the restraint intensity in circular patch welding as a parameter. Meanwhile, severity of the mechanical restraint condition in the plastic range can not be directly evaluated by using the restraint intensity. However, the relative severity of the mechanical restraint may be evaluated by using the restraint intensity only in the limited range.