Finite element model for modal analysis of engine-transmission unit: numerical and experimental investigations

The scope of this paper is to enhance the reliability of finite element models by taking uncertain parameters of an underlying structure into account. Such parameters can be system-related (e.g. geometry, material behavior, boundary conditions and mesh density) or influenced by general assumptions in the process of modeling. Here, an engine-transmission assembly is studied. This investigation develops instructions on how detailed a numerical model must be built in order to get satisfactory results for each component. For this purpose, the system’s eigenfrequencies are computed numerically and compared to experimental results from a laser Doppler vibrometer (LDV). Within this contribution, finite element models based on computer aided design (CAD) and computer tomography (CT) data are chosen. By choosing an engine-transmission assembly with unusually high manufacturing deviations, the effect of geometry variations is highlighted. Furthermore, after developing sufficient knowledge of the dynamic behavior and the simulation accuracy for single components, the parts are bolted together and the complexity of the problem is increased. This work presents some limitations of finite element modeling, which can be useful to find the most accurate concept for modeling the real dynamic behavior.