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The focus of this research is to perform a detailed investigation of the tradeoffs between mass, efficiency, service factor (SF), power factor (PF), and cost of commercially available induction machines (IMs). To support this effort, data from a large number of IMs is used to establish Pareto-optimal fronts between these competing objectives. From the Pareto-optimal fronts, relatively straightforward models are formulated for the mass versus loss, cost versus loss, SF versus mass, PF versus cost. Parameters of the models are obtained using a genetic algorithm (GA).

Flexible polyurethane foam is the main cushioning element used in car seats. Optimization of an occupied seat's static and dynamic behavior requires models of foam that are accurate over a wide range of excitation and pre-compression conditions. In this research, a method is described to estimate the parameters of a global model of the foam behavior from data gathered in a series of impulse tests at different settling points. The estimated model is capable of describing the responses gathered from all the impulse tests using a unique set of parameters. The global model structure includes a nonlinear elastic term and a hereditary viscoelastic term. The model can be used to predict the settling point for each mass used and, by expanding the model about that settling point, local linear models of the response to impulsive excitation can be derived. From this analysis the relationship between the local linear model parameters and the global model parameters is defined.

Numerical simulations are performed to investigate noise generated by flow in automotive HVAC ducts. A hybrid computational method for analyzing flow noise is applied: Large Eddy Simulation (LES) for predicting flow fields and Multi-domain boundary element method for predicting acoustic propagation. LES gives time-resolved solutions of flow velocity and pressure fields. By applying the acoustic analogy theory, the unsteady flow parameters are translated into sound source in evaluating the acoustic propagation. The computational result shows the noise caused by the HVAC ducts is strong. The noise is of broadband with a peak value at 370Hz. A major contribution of the noise generation is from the center ducts. Two design modifications of the center ducts are explored to regulate the flow structures with the ducts for reducing noise generation. Test results demonstrate the effectiveness of the modifications.

A unique concept for a multi-body test rig enabling the simulation of longitudinal, steering and vertical dynamics was developed at the Institute for Mechatronic Systems (IMS) at TU Darmstadt. A prototype of this IMS test rig is currently being built. In conjunction with the IMS test rig, the Vehicle Terrain Performance Laboratory (VTPL) at Virginia Tech further developed a full car, seven degree of freedom (7 DOF) simulation model capable of accurately reproducing measured displacement, pitch, and roll of the vehicle body due to terrain excitation. The results of the 7 DOF car model were used as the reference input to the multi-body IMS test rig model. The goal of the IMS/VTPL joint effort was to determine whether or not a controller for the IMS test rig vertical actuator could accurately reproduce wheel displacements due to different measured terrain constraints.

The identification of the propulsion noise of turbofan engines plays an important role in the design of low-noise aircraft. The noise generation mechanisms of a typical turbofan engine are very complicated and it is not practical, if not impossible, to identify these noise sources efficiently and accurately using numerical or experimental techniques alone. In addition, a major practical concern for the measurement of acoustic pressure inside the duct of a turbofan is the placement of microphones and their supporting frames which will change the flow conditions under normal operational conditions. The measurement of acoustic pressures on the surface of the duct using surface-mounted microphones eliminates this undesirable effect. In this paper, a generalized acoustical holography (GAH) method that is capable of estimating aeroacoustic sources using surface sound pressure is developed.

The renewed interest in electric and hybrid-electric vehicles has been prompted by the drastic rise in oil prices in 2008 and launch of new initiatives by the Federal Government. One of the key issues is to promote the incorporation of electric drivetrain in vehicles at all levels and particularly with emphasis on educational activities to prepare the workforce needed for the near future. Purdue University has been conducting a Grand Prix for over 50 years with Gas-powered Karts. In April 2010, an annual event was initiated to hold an EV Grand Prix where 17 EV Karts participated in the competition. Four of the participating teams comprised of Purdue students in a new graduate course for EV design and fabrication. Using the basic framework of the gas-powered Kart, an electric version was developed as a part of this course. Other participants were also provided with the guidelines and design parameters developed for the course and competition.

Two structure-borne and two airborne paths were measured on 99 “identical” Isuzu RODEOs and 57 “identical” Isuzu pickup trucks. Significant effort was made to control measurement variability but not environmental (climate) variations. A record was kept of the tests of a reference vehicle over the variation of environmental factors. The frequency response functions (FRFs) of the reference vehicle varied by approximately 2-4 dB over the frequency range 0-500 Hz for the structure-borne paths and over 0-1000 Hz for the airborne paths due to measurement and environmental variations. The FRFs of the fleet varied by as much as 5-10 dB over the same frequency range. In this paper, the vehicle tests are described. The reference and the fleet data are shown in raw form. Reduced data and implications of the results are also discussed.

In this paper it is shown that time-frequency analysis of a transient structural response may be used to identify the wave-types carrying significant energy through a multi-element structure. The identification of various wave-types is possible since each is characterized by its own dispersion relation, with the result that each wave-type may be associated with characteristic features in the time-frequency domain representation of a structural response. For multi-element structures, propagating energy can be converted from one wave-type to another at the junction of the elements. Consequently, for those structures, the characteristic features in the time-frequency domain consist of the superposition of features associated with propagation in each element. In the work described here, the Wigner Distribution has been used to obtain time-frequency domain representations of structural transient responses.

The mobility modeling technique is applied to the structure-borne noise path through a vehicle suspension. The model is developed using measured FRF data taken on the isolated components of the suspension and body structure of a midsize sedan. Several important modeling issues of suspensions are resolved. It was determined that multiple degrees of freedom are required to model the coupling at joints between the suspension and body structure. The investigation also demonstrated that bushings should not be included in the measurements used to develop these models and should be added later using simplified bushing parameters. The importance of transfer mobility information between the various suspension attachments was also investigated. The agreement between the mobility model predictions and the measured FRF data for the overall system is better than similar data published in the literature to date.

The Nexus vehicle was designed and built for Transport Canada at the University of Saskatchewan to demonstrate that a safety compliant single passenger commuter vehicle could attain extremely low fuel consumption rates at modest highway speeds. Experimentally determined steady state fuel consumption rates of the Nexus prototype ranged from 1.6 L/100 km at 61 km/hr up to 2.8 L/100 km at 121 km/hr. Fuel consumption rates for the Society of Automotive Engineers (SAE) driving cycle tests were 4.5 L/100 km for the SAE Urban cycle and 2.0 L/100 km for the SAE Interstate 55 cycle. The efficiency of the power train was determined using a laboratory dynamometer, enabling the road test results to be compared to the results from an energy and performance simulation program. Predicted fuel economy was in good agreement with that determined experimentally. Widespread use of single passenger commuter vehicles would substantially reduce current transportation energy consumption.

The authors relate their experience in teaching a senior level Computer-Aided Design (CAD) course in Mechanical Engineering using advanced Computer-Aided Engineering software. The course balances the theory and the need for hands-on experience with commercial CAD software in solving practical design problems. Students are given assignments ranging from simple 3D modeling exercises and 2D finite element analyses to an optimization project requiring more advanced 3D modeling and analysis. Where possible, analytical solutions are found and compared to the finite element results. The software allows the students to explore much more complex problems than would have otherwise been possible.

In experimental work, it is well known that measured values are not exact. Statistical treatment of uncertainty in measured values is common. The propagation of uncertainty in measured values into calculated values is examined. This technique of uncertainty analysis presented provides a rigorous mathematical technique for the analysis of uncertainty propagation from experimentally measured values into calculated results. The method of uncertainty analysis is introduced in general and an application to the momentum equation is examined to demonstrate the technique. The example presented demonstrates the effectiveness of the technique by demonstrating the growth of uncertainty in the calculated results around a singularity in the equations.

A finite element model (FEM) of elastic noise control materials like polyurethane foams is presented in this paper, and its implementation in two-dimensional form as a computer program is discussed. So that realistic noise control treatments could be studied, methods for coupling the foam FEM with conventional acoustical and structural finite elements are also described. The validity of the foam FEM is demonstrated by computing the sound absorption and transmission characteristics of simple coupled air/foam/panel systems and by comparing the results with existing experimental and analytical results for such arrangements. The FEM has been used to show that the constraint of a foam layer at its edge stiffens the foam acoustically. In addition, it has been found that the constraint of the ends of the facing panels in a foam-lined double panel system increases the sound transmission loss significantly at low frequencies.

The object of the work reported here was to relate the acoustic intensity level measured near the contact patch of a driven tire on a passenger vehicle with the passby noise levels measured at a sideline microphone during coast and cruise conditions. Based on those measurements it was then possible to estimate the tire noise contribution to the passby level measured when the vehicle under test was accelerating. As part of this testing program, data was collected using five vehicles at fourteen passby sites in the United States: in excess of 800 data sets were obtained.

The Porous Ceramic Tube - Nutrient Delivery System (PCT-NDS) offers means to control water availability to plants under non-standard gravities. It is hypothesized that control can be obtained by applying suction pressure within the ceramic tubes. The research objectives include verifying the presented control equation for the PCT-NDS under micro-(less than 1 g) and hyper- (greater than 1 g) gravities. Experiments were conducted on a KC-135 subjecting the system to near-zero to 2 g's and to sustained hyper-gravities upto 10 g's using a centrifuge. Results indicated that the water availability can be controlled through applied suction pressure.

Farmers are a small group, mostly college educated who run multi-million dollar yearly operations. Recent favorable economics has allowed this sector to look at new technology and determine the best way to invest in it. New considerations in the last few years have led to minimum/alternative tillage and planting, site specific farming decisions and small technology groups of farmers. The authors have put together their thoughts and wants which should be evaluated by future suppliers of technology and farm machinery.

Presented in this paper is the nonlinear modeling and control of the idle speed of a Ford 4.6L-2 valve V-8 fuel injected engine. The nonlinear model of the engine is based on a Hammerstein type model which is identified through input-output data without a priori knowledge of the engine dynamics. The nonlinear model is used in a frequency domain controller design methodology to achieve the performance goal of maintaining the engine idle speed within a prespecified asymmetric output tolerance despite external torque disturbances. An experimental verification of the nonlinear controller is included.

Modern diesel engines typically utilize pulse-turbocharging where an increase in exhaust gas transport efficiency is achieved at the expense of creating a highly unsteady flow through the turbine which may have a detrimental effect on turbine performance. As the turbocharger plays a major role in the performance and emissions of the engine system, the characterization of on-engine turbocharger aerodynamics is critical. Thus, this paper is directed at the investigation of the turbocharger turbine volute inlet flowfield on an in-line, six cylinder, diesel engine. Specifically, Particle Image Velocimetry (PIV), a quantitative non-intrusive whole flowfield measurement technique, is used to perform a detailed study of the on-engine pulsating flowfield at the volute inlet of the twin-entry turbocharger turbine.

A feedback controller bas been developed using robust control techniques to control the sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain loop shaping techniques. System uncertainty, sound pressure level reductions, and actuator constraints are included in the design process. For the wind noise problem, weighting factors have been included to distinguish between the importance of modes that radiate sound and those that do not radiate. The wind noise controller has been implemented in the quiet wind tunnel facility at the Ray W. Herrick Laboratories at Purdue University. A multiple-input, multiple-output controller using accelerometer feedback and shaker control was able to achieve control up to 1000 Hz. Sound pressure level reductions of as much as 15 dB were achieved at the frequencies of the plates modes. Overall reductions over the 100-1000 Hz band were approximately 5 dB.

An analytical model based on “vortex sound” theory was investigated for predicting the frequency, the relative magnitude, the onset, and the offset of self-sustained interior pressure fluctuations inside a vehicle with an open sunroof. The “buffeting” phenomenon was found to be caused by the flow-excited resonance of the cavity. The model was applied to investigate the optimal sunroof length and width for a mid-size sedan. The input parameters are the cavity volume, the orifice dimensions, the flow velocity, and one coefficient characterizing vortex diffusion. The analytical predictions were compared with experimental results obtained for a system which geometry approximated the one-fifth scale model of a typical vehicle passenger compartment with a rectangular, open sunroof. Predicted and observed frequencies and relative interior pressure levels were in good agreement around the “critical” velocity, at which the cavity response is near resonance.