Restraint Modal Analysis of Three-cylinder Diesel Engine Blocks

The three dimensional model of a three-cylinder diesel engine block is established by using UG 5.0 software,and the modal analysis of the engine block is carried out under four different constraint conditions using Lanczos method.Through the analysis,the inherent frequencies and the modal shapes of the first 10 order modes are obtained.The results are compared one another.Based on the comparisons,it is discovered that the inherent frequencies and the corresponding vibration modes are quite different for different constraint conditions.In addition,the weak portions of the engine block vibration are found by modal analysis,and the corresponding modifications are put forward,which may provide a reference for further structural design and dynamic response analysis of the diesel engine block.