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A method is presented to evaluate diesel engine structure borne noise differences caused by component design changes of the engine assembly. A flexible multi-body dynamics model is used to develop loads on the engine due to combustion, piston-liner interactions, and interactions at the main bearings. These loads are applied to an engine finite element model for frequency response analysis. The frequency response analysis is then varied by changing the component design of the engine assembly. Surface velocities and modal participation factors are determined from the frequency response. The participation factors are then used in a modal acoustic transfer analysis to compute the sound power. Comparisons are made between assemblies and to experimental data.

In this report, a practical finite element design method is developed for metal/polymer/metal laminates. An analysis is presented which will predict the damping characteristics of laminated structures. Predictions of natural frequencies, loss factors, and frequency responses are compared to experimental data and closed form solutions. The analysis is then used to show a reduced vibration response with the laminated design as compared to a metal design. With the methods presented here, components may be designed which reduce vibrations, noise, and fatigue wear by means of a practical finite element approach. Vibration problems are avoided, allowing other specifications, such as weight or tooling concerns, to be used to size the component.