Study On6L21/31Marine Medium-speed Diesel Virtual Prototype Techique

In the practice of marine diesel engine, the crankshaft and connecting rod mechanismis undoubtedly the most important part. The quality of its every component will affect theoperation of the whole mechanism, or even operation efficiency and service life of thewhole diesel engine, and have a bad influence on enterprise.Aimed at the situation that flaws appeared in crankshaft of individual6L21/31marinemedium-speed diesel engine owned by Zhenjiang CME Co. Ltd in the process of operation,and affected product quality, based on the basic theory of Multi-body dynamics andRigid-flexible coupling dynamics, the application situation of virtual prototyping wasdiscussed. The problem was found, and suggestions are given.The main points of this thesis were summarized as following:(1) The kinematics and dynamics of the crankshaft and connecting rod mechanism of6L21/31marine medium-speed diesel engine were analyzed and calculated with the methodof kinematics and dynamics.(2)The3D solid model of the crankshaft and connecting rod mechanism and correlativecomponents was built by Pro/E, and based on virtual assembly module of Pro/E, theassembly of3D model for the crankshaft and connecting rod mechanism about6L21/31marine medium-speed diesel engine was completed.(3) The method that the combination of Pro/E and ADAMS was used to transform the3D solid model into Multi-body dynamics simulation model, then the simulation research ofkinematics and dynamics of6L21/31marine medium-speed diesel engine was carried out.(4) The crankshaft of6L21/31diesel was processed by the flexible treatment in ANSYS,and then virtual prototype model of Rigid-flexible coupling was established in ADAMS,finally, the dynamic stress simulation of the crankshaft was completed.Through the study on the front several aspects, two conclusions can be drawn asfollowing:(1) Based on the virtual prototype technology, the simulation of kinematics, dynamicsof Multi-body and dynamic stress of Rigid-flexible coupling of the crankshaft andconnecting-rod mechanism of6L21/31marine medium-speed diesel engine were completed,and more accurate kinematics and dynamics features, maximum stress and position of thecrankshaft were obtained with higher accuracy. Reliable theoretical basis for the futheroptimization design and performance improvement of the crankshaft and connecting rod mechanism was provided.(2) Based on the front research result obtained, performance simulation andoptimization can be completed by using the virtual prototype technology instead of thephysical prototype of6L21/31marine medium-speed diesel engine. Compared withtraditional design and research, this method not only reduced the cost and period of researchand development, but also improved the design standard. So, this method had positivesignificance for the related research on the other types of marine diesel engine.