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There has been an ongoing interest in replacing mineral oil with more biodegradable and/or fire-resistant hydraulic fluids in many mobile equipment applications. Although many alternative fluids may be more biodegradable, or fire-resistant, or both than mineral oil, they often suffer from other limitations such as poorer wear, oxidative stability, and yellow metal corrosion which inhibit their performance in high-pressure hydraulic systems, particularly high pressure piston pump applications. From the fluid supplier's viewpoint, the development of a definitive test, or series of tests, that provides sufficient information to determine how a given fluid would perform with various hydraulic components would be of interest because it would minimize extensive testing. This is often too slow or prohibitively expensive. Furthermore, from OEM's (original equipment manufacturer's) point of view, it would be advantageous to develop a more effective, industry accepted fluid analysis screening.

The energy finite element method (EFEM) was developed to utilize available finite element geometric models for high frequency structural-acoustic analysis. Statistical Energy Analysis (SEA) is a lumped parameter approach currently in widespread use for high frequency analysis. In this investigation, EFEM and SEA models were developed for components of a heavy equipment cab. A generalized joint process (GJP) was developed and used for processing the various joints between structural subsystems. The structural predictions were compared to each other as well as to measurements.

A new laboratory method has been developed to evaluate the acoustical properties of expandable and other automotive sealants. These materials are used to reduce wind, road, and powertrain noise transmission into passenger compartments. In the new method, ASTM E 1050 absorption measurement equipment is used along with a new sample holder, a downstream microphone holder (providing two additional microphone locations) and an anechoic termination. These additions permit measurement of normal incidence transmission loss as well as absorption. It is intended to encourage adoption of this method as a standard way of quantifying the acoustical performance of sealants and sealing composites in automotive noise control applications.

Despite numerous research efforts, there is no reliable and widely accepted tool for the prediction of erosion prone material surfaces due to collapse of cavitation bubbles. In the present paper an Erosion Aggressiveness Index (EAI) is proposed, based on the pressure loads which develop on the material surface and the material yield stress. EAI depends on parameters of the liquid quality and includes the fourth power of the maximum bubble radius and the bubble size number density distribution. Both the newly proposed EAI and the Cavitation Aggressiveness Index (CAI), which has been previously proposed by the authors based on the total derivative of pressure at locations of bubble collapse (DP/Dt>0, Dα/Dt<0), are computed for a cavitating flow orifice, for which experimental and numerical results on material erosion have been published. The predicted surface area prone to cavitation damage, as shown by the CAI and EAI indexes, is correlated with the experiments.