A REPAIR MANAGEMENT SYSTEM FOR FATIGUE CRACKS IN SHIPS

Many ships experience fatigue cracking in their Critical Structural Details (CSD). Due to the need to limit the out-of-service time in shipyards, traditional fatigue analyses rarely have been used to guide repair decisions. Repair decisions are most often based on the experience of the shipyard repair personnel. This paper details a Simplified Fatigue Analysis (SFA) that has been developed to facilitate evaluations of alternative repair methods for ship CSD. The stress reductions due to repairs were determined by performing finite element analyses. An interactive personal computer program has been developed to facilitate application of the SFA in shipyards. The failure lives of alternative repairs can be quickly estimated. Repair cost-durability tradeoffs can be readily developed. The approach is demonstrated with an example of evaluation of repair alternatives for fatigue cracks in side shell CSD of a class of oil tankers.