Dynamicanalysis Of A Diesel Engine's Structural System

Dynamic analysis of structure, as an indispensable step in a mechanical product development design process, has been concerned a long time. It not only can analysis the stiffness distribution of a component to find out the weak link, can also show us the dynamic characteristics of the structure. Then according to the working conditions, optimization of the structure was conducted to get more reasonable, economic products. Usually these researches were achieved through the theoretical analysis and experiment, and the finite element analysis is one of the main methods in complex structure analysis.Three main aspects-finite element modeling, dynamic characteristic analysis and structural optimization were studied in this paper, which takes the main components of a diesel engine as the research object and uses the finite element method and experimental analysis as the research method.Mesh is the most important step to conduct a finite analysis. The accuracy of analysis results is mostly depended on the grid quality. In this paper, a set of convenient, fast, better quality mesh method was explored in finite element modeling of finite element modeling of diesel engine's body and cylinder head. It will be helpful for design and optimization of complex structure.Modal analysis of the main component (such as the body and head, crankshaft, the oil pan, cylinder shell and gear room cover) and the typical components (the combination of cylinder head, crankshaft system) were conducted. Comparing calculation results with the test values, the difference is mostly below 10%, which prove the finite model can be use to the subsequent simulation and optimization.In order to reduce the noise of a diesel engine, the vibration and noise were tested to get the dangerous frequency. Oil pan was founded to be one of the main noise sources. So optimization of oil pan was conducted in the end.