Modal Analysis of Transmission Housing Using Finite Element Modeling for Various Assembly Conditions

In recent years the solution of the dynamic behavior of a structure by the application of the Finite Element Method has become more popular. Modal analysis is the process of determining the inherent dynamic characteristics of a system. The solver used in this analysis will give the Eigen values and Eigen vectors which represent the natural frequencies and corresponding mode shapes by solving the Eigen system. The extracted natural frequencies and mode shapes define the dynamic characteristics of the system. Free-free and constrained modal analyses are the two major types, which explains the dynamic nature of the system with and without assigned boundary conditions respectively. In this research project, the main aim is to arrive an appropriate modal analysis procedure and setting up a guideline to execute the modal analysis of transmission housing assembly using numerical analysis based finite element modeling by performing both free-free and constrained modal analysis for various assembly conditions. Modal analysis of transmission housing is a challenging task because of the complexity in its structure and the presence of various internal components. In free-free modal analysis the entire assembled model is analyzed with assumptions like surface to surface interactions and one dimensional beam elements separately, in order to achieve the bolted connections. Further in constrained modal analysis one more assumption is added that the mass of internal components and oil. In all the cases, the natural frequencies and mode shapes are extracted, documented and compared to investigate the influence of the various assembly conditions and ensure that transmission housing will not meet the resonant condition in its operating range.