Research On Marine Ship Diesel Engine Crankshaft Fatigue Initiative Reliability On Full-life Cycle

Diesel engine crankshaft is one of the most complex forced components, which in the cyclical changes of gas pressure and reciprocating inertia loads, and also under the effect of rapid changes in internally generated alternating bending and torsion stress, thus prone to fatigue failure. With the enhancement and continuous improvement of internal combustion engine, the working conditions of the crankshaft deteriorated, crankshaft fatigue reliability analysis is a very necessary and urgent work. However, the current research and application of crankshaft reliability are often confined to the reliability evaluation after the products have been shaped, so the hidden defects can not be overcome in the design stage of production. Therefore, searching for a viable and effective method of calculating the reliability, and expansion it to the product's entire life cycle is very useful to improve product quality as the same as reduce the whole cost.In this paper, marine diesel engine crankshaft is the main object, trying to explore a scientific approach to achieve the calculation of fatigue initiative reliability of the product throughout the entire life cycle just like crankshaft is the most important research goal. First of all, paper theoretically a more comprehensive analysis of the fatigue damage model and the fatigue reliability of research methods, and gradually settled into the center of gravity based on toughness, fatigue cumulative damage model and the research of the structural reliability methods; Secondly, it summarizes the crankshaft Environment load theory and computational model for the preparation of relevant technical methods for the subsequent calculation of fatigue life and reliability calculations to prepare the basic information and necessary conditions; then carry out the above theoretical approach to the crankshaft fatigue reliability of a specific analysis of the initiative to go, support model for simulation and fatigue damage and reliability of the algorithm achieved; Finally, the main results of the study through the MATLAB software programming and VB called pop visual analysis software ANSYS, ADAMS, UG, etc. in order to focus on the research and description clearly.This major work and the relevant conclusions of this paper:(1) Systematic study hold on the existing fatigue damage model, selected and explored the cumulative fatigue damage theory in-depth based on material toughness, and created applicable fatigue damage accumulation model to the crankshaft on material toughness dissipation, which goes for fatigue damage and fatigue life calculation.(2) Review and analysis the current methods of fatigue reliability of the technology, with the help of structural reliability theory, explore the relationship between fatigue life and reliability, mainly from the random variable, function and reliability function algorithm the three core issues, then proceeding to establish a method of the fatigue reliability of the crankshaft based on structural reliability calculation model.(3) Through the dynamics of the crank-connecting rod mechanism and the related calculation of lubrication theory, expounded the crankshaft-related computing model and finite element analysis techniques, a detailed description of the payload data rain-flow counting method of operating principles and procedures for the establishment of the principles of spectrum, using three-dimensional physical rigid-flexible coupling dynamic simulation experiments, to obtain relevant data in order to implement the initiative crankshaft fatigue reliability of algorithms.(4) To the specific design parameters of crankshaft (including materials, dimensions, etc.), establish a simulation model, transfer the complexity factors and the random variability to the computer model, and in the mathematical model, analysis the role of the load on the crankshaft, as well as the stress response and other information to demonstrate the reliability of the whole life cycle of the initiative.(5) From the power flow and data flow, paper completed the analysis of crankshaft fatigue initiative reliability calculation and prepared a prototype system FIRS (Fatigue Initiative Reliability System) based on VB.