The Dynamic Characteristics Analysis Of6S50MC-C Diesel Engine

Marine diesel engine is an important device of ship’s main propulsion power. The skeleton of marine two-stroke low-speed diesel engine, which consists of cylinder block, frame and bedplate, has to be suffered complex forces. At the same, the development direction of the marine diesel engine is super-long stroke, it’s overall stiffness is be reduced continuously. Therefore, the dynamic characteristics analysis of the diesel engine has an important significance to reveal the relationship of outer simulating force and the inherent characteristics. The analysis provides the premise to the designers that they can design the engines with high intension and low vibration. So, this paper takes the main body of6S50MC-C diesel engine as an example, having a detailed analysis of the engine by using finite element analysis software Hyperworks.Create the three dimensional solid model of cylinder block, frame and bedplate by the software of Pro/Engineer, and then, manual meshing the solid model in HyperMesh. By making free modal analysis and constrained modal analysis of the diesel engine in Radioss, it get the first18order modes and frequencies of the diesel engine. The rules of the modes and natural frequencies is analysised, the results show the relative distribution of the vibration magnitude in the diesel engine and reveals the characteristics of modes in various frequency bands.It is obtained the curves of cylinder cover bolts forces, crosshead component side thrust and bearing forces, which is changes over time according to the the gas pressure trace inside the cylinder, and by studying on the dynamics simulati on of crank-connecting rod mechanism of diesel engine. And these forces are ac curately applied on the FE model. The transient response analysis of the diesel e ngine can be started.After the transient response analysis of the diesel engine, the dynamic stress and vibration status of the surfaces can be obtained, it can also draw the time-processing curves of the key nodes, revealing the vibration status of the diesel engine in a cycle.