Diesel Engine System Of Modal Analysis

The dynamic characteristic analyses of the structural systems have become increasingly in structural dynamics field. Based on the engineering research on complex structures of the diesel engine, this paper systematically makes the dynamic characteristic analysis and experimental verification of the main parts and combination structures in the diesel engine study on 12V165 diesel engine, and draws a conclusion about the theoretical calculation results being keep with those achieved in experiment. This work establishes a foundation on the dynamic response calculation, the dynamic characteristic analysis of the diesel engine and optimization in structural design step by step, simultaneously finds a way for improvement of the structures. Based on the mode analysis theory, this paper analyzes the component and working situation of the diesel engine, summarizes international and native research results on the dynamic characteristic analyses of the diesel engine, systematically applies the finite element method (FEM), synthetically considers improving accuracy and reducing to a lower rank. By ANSYS software, the finite element models of the diesel engine with engine block, crankshaft and cylinder head are constructed in this paper. This overcome the difficulty in application of the finite element modeling with plate and shell, and simultaneously calculates and analyzes every free modal parameters of the models. This paper mainly studies the dynamic characteristics of the engine block and proposes improving measures for its structure.The dynamic characteristic analyses of the structures are required to describe structural systems accurately in theory, the method is a detachable structure, continuous system has become distributed relate structure in a node Through the hypotheses of the structural material and shape, the simplification of the structural constraints and joints, the theoretical calculation models are established by the finite element techniques, for accumulating bias about model structure, order and parameter, are their results reliability? This is required to be verified in experiment. Based on experimental modal method, the block, crankshaft, cylinder head and the assembly of the diesel engine are experimented, and free modal parameters achieved by finite element method coincide with those achieved in experiment, which shows the correctness of the models and adopts the proper research methods. The diesel engine is composed of a lot of the complex components and parts. If its properties are studied, it is required to research the dynamic characteristics of the assembly. Based on the modal synthesis method, this paper analyzes the situation of the coupling, demonstrates three-substructure formula by the dynamic substructure technique, establishes the finite element models of the coupling, simultaneously calculates and analyzes its free modes, roughly handled the joint of the combination structure.