Methods for Non-Destructive Analysis of Fatigue in Cranes

Sudden, catastrophic fatigue failures in 40 to 50 year old Navy cranes pose a significant danger to personnel and facilities. These aging cranes are currently used to lift nuclear materials and other sensitive payloads. Nondestructive Evaluation (NDE) methods of fatigue crack analysis are urgently needed, before more cranes experience failures leading to the uncontrolled dropping of the load. In the proposed effort, TRI/Austin will investigate the background of the problem by visiting crane sites and examining the equipment. A worldwide information search will be conducted, focusing on NDE technique for determining crack size, orientation, and location, and NDE techniques for in-situ material toughness evaluation. Special emphasis will be placed on Acoustic Emission (AE) and ultrasonic techniques, which will be investigated both in the literature and in the laboratory. A technology synthesis will be performed to select NDE methods applicable to the crane problem. Prototype laboratory tools will be developed and tested to prove the feasibility of the approach. A final comprehensive report will be prepared and delivered at the end of the ef fort. TRI/Austin will team with Dr. Tim Fowler, who is recognized worldwide as an expert in Acoustic Emission NDE.