| Diesel engine as the heart of a ship occupies a pivotal position, the current main trend of its development is safe, reliable, lightweight structure. Therefore, the prediction to the structural fatigue life and the studies of its optimization design become an urgent task.Oil pan as an important component of the diesel engine, its main function is storing lubricants and sealing the entire body, in addition to cooling the engine oil. Oil pan's area is large and is made of thin steel plate, it easily cause vibration and noise when a diesel engine is working. Meanwhile, in some stress concentration areas, like right angles, etc., stress fatigue will happen, resulting in cracks and reduction of its life.Under the condition of dynamic loading, the study of diesel engine oil pan in the aspects of dynamic stress analysis, structural fatigue strength and the optimal design is relatively less at home and abroad, mainly due to its complex structure, expensive on-site structural durability testing, and the difficult ascertainment of loads that the shell is bearing and of the boundary conditions,etc. In this paper, the project "Dynamic stress analysis and experimental test of marine diesel engine mountings" is supported by CSIC. Based on finite element, multi-body dynamics and testing theory, the diesel engine oilpan is analyzed for dynamic stress calculated and experimental test, this thesis focuses on fatigue analysis and life prediction of diesel engine oil pan, and afterwards, devoting to the optimum design of its structure. Specific contents are as follows:(1) Based on ADAMS Software, using the mode superposition method, dynamic stress of engine block and oil pan calculation model is combinated, mainly including geometric modeling, finite element analysis, multi-body dynamic simulation, etc., trying to find out the dynamic stress (dynamic load) of oil pan, offering data support for subsequent fatigue analysis and life prediction.(2) The dynamic stress testing of the oil pan, comparing the result of which with theoretical results, in order to improve the finite element model for the next step of calculation. (3) Analyzing the fatigue type of diesel engine oil pan, establishing its load spectrum according to the calculated dynamic stress, and setting the fatigue properties of oil pan in accordance with its material character, and then calculating its fatigue condition theoretically with assistance of fatigue analysis software MSC. Fatigue.(4) Based on Optistruct module of HyperWorks software, topology optimization and size optimization on the basis of the analysis of its fatigue life, reducing its weight under the premise of ensuring the garrenteed life, in order to improve its economical efficiency and provide a useful reference to manufacturers. |
