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Bearing press fits have a wide range of application in ground vehicles and are typically governed by longstanding rules of thumb for designs that conform to past successful design geometries and practice. However, in unusual applications such as a gear box designed to also bear external loads, the combined stress states require finite element analysis (FEA) that accounts for the press fit, the bearing loads due to torque transmission, and the external loading. Therefore accurate prediction of press fit stress states are required to construct complete solutions to gear box fatigue life prediction and in particular to predict mean stress states. Current FEA tools provide a variety of analysis methods with which to approach the problem of press fit mechanics.

A broad range of vehicle dynamic models exists for predicting tracked vehicle dynamic performance. This range begins with the point mass models embedded in automotive performance simulations that are more focused on powertrain performance, to commercial rigid body dynamics codes that model the individual track blocks and the detailed contact interactions of the drive lugs and wheel guides. Between these extremes are well known modeling tools such as the NATO Reference Mobility Model (NRMM) vehicle dynamics (VEHDYN) module and several commercial and custom purpose-driven modeling tools. The fidelity of these models can be roughly categorized from their theoretical basis, but others, such as the various means of representing track require numerical experiments. This paper presents some standard verification tests and results that help quantify the fidelity levels of these models.

For vehicle interior noise abatement and noise treatment, it is desirable to quantitatively determine sound power contribution from each vehicle component because: (1) Sound packages can be designed with maximized efficiency if sound power contribution into a vehicle is known; (2) Acoustic leakage inside a vehicle can be determined by comparing sound power contributions from adjacent vehicle components; and (3) Sound power flow information can be used to verify Statistical Energy Analysis (SEA) model. Simple sound pressure measurement does not produce any information about sound power flow and is unsuitable for these purposes. This paper describes an in-situ determination of sound power contribution inside a vehicle using sound intensity measurements. Sound power contribution from each vehicle component was determined for engine noise at idle speed. Acoustic leakage in the vehicle was also determined.