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This paper documents an inverse visible element Rayleigh integral (VERI) approach. The VERI is a fast though approximate method for predicting sound radiation that can be used in the place of the boundary element method. This paper extends the method by applying it to the inverse problem where the VERI is used to generate the acoustic transfer matrix relating the velocity on the surface to measurement points. Given measured pressures, the inverse VERI can be used to reconstruct the vibration of a radiating surface. Results from an engine cover and diesel engine indicate that the method can be used to reliably quantify the sound power and also approximate directivity.

Joint strength of a vibration welded air intake manifold has been optimized by controlling the process parameters. Key process parameters are: Clamp pressure, bead melt down displacement and vibration amplitude. The present study has investigated the combined effect of the vibration welding process parameters on the weld joint strength of a manifold by using a factorial DOE (Design of Experiment) with center points. The result of the DOE study revealed that the burst strength can vary as much as 50% across the process window investigated. Response surface of strength, which was developed as a function of the process variables, can be used for process control in the production plant. The weld strength values of Nylon 6 and Nylon 66 materials are also compared across the wide range of the process window.

Automatic code generation from models is actively used at Caterpillar for powertrain and machine control development. This technology was needed to satisfy the industry's demands for both increased software feature content, and its added complexity, and a short turn-around time. A pilot development effort was employed initially to roll out this new technology and shape the deployment strategy. As a result of a series of successful projects involving rapid prototyping and production code generation, Caterpillar will deploy MathWorks modeling and code generation products as their department-wide production development capability. The data collected indicated a reduction of person hours by a factor of 2 to 4 depending on the project and a reduction of calendar time by a factor of greater than 2. This paper discusses the challenges, results, and lessons learned, during this pilot effort from the perspectives of both Caterpillar and The MathWorks.

Medium-carbon, microalloyed forging steels represent a cost effective replacement of quenched and tempered grades. Their strength properties are derived from precipitation during cooling from the forging temperature. Because of the relatively high carbon content, vanadium is the most suitable addition to achieve precipitation strengthening. The effectiveness of vanadium is enhanced by the presence of nitrogen. For components subjected to impact loading, improvement in toughness is achieved by refining austenitic grains, pinning their boundaries by means of dispersed titanium nitrides. Precipitation strengthened ferrite-pearlite steels exhibit superior machinability compared to that of quenched and tempered alloy steels. As a result, the total machining costs are substantially reduced compared to the costs of machining heat-treated steels. The frequency of tool breakage and tool changes decrease dramatically, virtually eliminating line scrap and unnecessary downtime.

Very large scale, 3D, viscous, turbulent flow simulations, involving 840,000 finite volume cells and the complete form of the time-averaged Navier-Stokes equations, were conducted to study the mechanisms responsible for total pressure losses in the entire intake system (inlet duct, plenum, ports, valves, and cylinder) of a straight-six diesel engine. A unique feature of this paper is the inclusion of physical mechanisms responsible for cylinder-to-cylinder variation of flows between different cylinders, namely, the end-cylinder (#1) and the middle cylinder (#3) that is in-line with the inlet duct. Present results are compared with cylinder #2 simulations documented in a recent paper by the Clemson group, Taylor, et al. (1997). A validated comprehensive computational methodology was used to generate grid independent and fully convergent results.

Caterpillar's inboard brake and final drive axle responds to customers needs for a lifetime service brake removed from the often hostile environment encountered by exposed shoe-drum or caliper-disc brakes. A multi-disciplined team was assembled to select the single most appropriate axle configuration. That team was composed of members of the three worldwide facilities which would manufacture the axles. After selection of the configuration, the team approach was continued from development thru production. Concurrent product and process design was felt to be the most efficient way to provide the customer with an enclosed brake and to modernize our plants manufacturing operations. This paper will identify the methods used to develop a cost effective manufacturable axle. Working the product design and manufacturing process together provided for a more manufacturable axle, in a shorter time frame, with less start-up problems compared to the traditional approach.

IMPLEMENTATION OF A SECOND GENERATION SOUND POWER TEST FOR PRODUCTION TESTING OF EARTHMOVING EQUIPMENT Caterpillar has developed an automated sound power measurement system that measures construction equipment sound levels before they leave the assembly plant. This paper describes the test system and gives the results of verification tests conducted at various manufacturing plants around the world. It was concluded that the new system allows Caterpillar to quickly and accurately acquire the data necessary to assure that their product meets its noise requirements.

Caterpillar has introduced a new concept that shatters previous ripping limitations. The D9L Impact Ripper has extended the ripping capacity and productivity of the standard ripper tractor in heavy construcion, mining, and quarry applications. This paper describes the design objectives, development program, component selection, and the demonstrated productivity of the D9L Impact Ripper.

The Challenger 65 agricultural tractor combines the best features of current four wheel drive machines; speed, on-road mobility, and operator comfort with the well recognized advantages of track-type machines; tractive efficiency and reduced soil compaction.

Engine tests were conducted on a production 2.5-liter V-6 engine to investigate the effects of spark plug tip designs on a 4-cycle SI engine of current technology. The data suggest that cyclic variation can increase when the ground electrode faces the primary intake port. Lean-operation limits were extended by the use of J-gap spark plugs as compared to surface-gap and ring-gap spark plugs at the conditions tested. The surface-gap type spark plugs lose some energy as the arc traverses the surface of the insulator. Voltage requirements decrease for reversed polarity at the part load conditions tested but increase at wide open throttle.

The paper details opportunities for electronic control of the pneumatic charging system of an air braked vehicle. Electronic control of the charging and drying functions can result in increased fuel efficiency and improved air quality. Control functions can be used to identify and warn of in-service issues, provide prioritized system charging for faster drive-away, and signal required preventative maintenance. The first portion of the paper describes current industry practice, as well as common issues that can result from those practices. This is followed by presentation of areas of improvement, where specialized control features result in energy savings, air quality increases and maintenance/downtime savings. This portion will focus on adaptive control of components used today, and will briefly discuss opportunities for the next generation of charging system devices. The final section of the paper presents the control logic and vehicle interface allowing for system integration.

A parametric simulation model of a steel-tracked feller buncher was developed1. This model can be used to predict the lift capacity, side tipping angles, grade-ability, and joint forces during a cutting cycle. The feller buncher is defined parametrically, allowing the user to quickly analyze different machine configurations simply by changing the value of a variable. Several simulations were performed to illustrate the application of the model.