INVESTIGATION OF POSSIBLE CAUSES FOR APPEARANCE OF A CRACK IN THE WELDED JOINT OF THE SHIP WINCH FRAME

Ship winches are one of the most important parts of the ship equipment since they perform the most responsible tasks on various ships. In the majority of cases, the ship winches are welded structures. All the necessary calculations according to required standards, that have to be done prior to actual execution of the structure, should also include the verification by the FEM. For the high reliability requirements to be met, the welded joints integrity of all the parts must be examined before they are assembled into the winch. After all the tests are conducted and the parts are assembled into the winch, the factory acceptance test (FAT) must be also done. During those tests all the flaws, which can appear during the manufacturing, must show. An appearance of a very unusual crack in the ship winch frame, which happened during the FAT, is described in this paper. The simulation by the FEM was performed to obtain the stresses at which the crack appeared. The possible causes for that crack appearance are considered. Some measures for reducing appearance of such cracks to a minimum are proposed, as well as certain directions for further research of this problem.