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Chromium Molybdenum Steel (AISI 4130), commonly referred to as “Chrome Moly”, is one of the most popular materials used in the construction of tubular space frames and chassis components for racing applications. Its high strength, light weight and comparably low material cost make the reasons for its popularity quite obvious. However, there is one problem that is commonly overlooked: maintaining the strength component of Chrome Moly in areas exposed to high levels of heat followed by rapid cooling during welding. This paper seeks to better understand the affects of cooling due to welding on the strength of Chrome Moly tubing.

A unique differential assembly was needed for the Lawrence Technological University (LTU) SAE Formula race car. Specifically, a differential was required that had torque sensing capabilities, perfect reliability, high strength, light weight, the ability to withstand inertia and shock loading, a small package, no leaks, the ability to support numerous components. In that regard, an existing differential was selected that had the torque sensing capabilities, but had deficiencies that needed to be fixed. Those deficiencies included the following: Differential unit was over 4 kg unmounted, with no housing. This was considered too heavy, when housed properly. Bearing surface was provided on only one end of the carrier. This design provides insufficient bearing surface to support either the differential housing or half-shafts The internal drive splines integral to the case are not optimized for a perpendicular drive/axle arrangement, such as, a chain drive.

Control of annoying noises such as buzzes, squeaks and rattles (BSRs) is particularly important for complex products such as automobiles. This importance has become even more significant as electric vehicles become more popular, eliminating much of the ambient background vehicle noise. A customer's perception of the durability and solidness of a vehicle is based largely on sensory responses such as sound. Recent advances in beamforming technology have the potential to change the way BSR audits and vehicle development testing are done. This paper introduces the application of spherical beamforming technology to BSR testing and provides test results showing the localization accuracy of a rigid spherical array system in a vehicle cabin.

All-wheel drive (AWD) vehicle performance considerably depends not only on total power amount needed for the vehicle motion in the given road/off-road conditions but also on the total power distribution among the drive wheels. In turn, this distribution is largely determined by the driveline system and its mechanisms installed in power dividing units. They are interwheel, interaxle reduction gears, and transfer cases. The paper presents analytical methods to evaluate the energy and, accordingly, fuel efficiency of vehicles with any arbitrary number of the drive wheels. The methods are based on vehicle power balance equations analysis and give formulas that functionally link the wheel circumferential forces with slip coefficients and other forces acting onto an AWD vehicle. The proposed methods take into consideration operational modes of vehicles that are tractive mode, load transportation, or a combination of both.

The 2000 Formula SAE Team at Lawrence Technological University (LTU) has designed a chain driven, three-piece aluminum differential unique from past years. This innovative design introduces an adjustable chain mount replacing conventional shackles. Made completely of aluminum, this device moves the entire rear drive train. The gear set remains to be limited slip with a student designed housing. The idea of an aluminum housing with manufactured gear set is a continued project at LTU. After cutting approximately 33% from the weight of the 1999 differential, the 2000 is geared toward a simpler, and smaller design, easier assembly and lighter weight. After reading this brief overview, the idea of this paper is to provide an understanding of the reasoning behind the choices made on the LTU driveline team. FIGURE 1

To obtain a maximum range for usable torque, Helmholtz theory is utilized to tune an Honda CBR 600 cc engine. The design objectives were to: 1) Increase performance by reducing pressure losses in the entire intake system; 2) Maximize the restrictor's design to increase airflow at lower pressure drops; 3) Improve throttle response through throttle body design and reduction of turbulence when full open; 4) Utilize runner design to improve tuning effects as predicted by Helmholtz resonance theory and; 5) Incorporate a plenum design with equal air distribution to all four cylinders.

Aerodynamics plays an important role in the dynamic behavior of a vehicle. The purpose of this paper is to evaluate external and internal aerodynamics of the 1999 and 2000 Lawrence Technological University Formula SAE vehicles. The external aerodynamic study will be limited to form and interference drag and the evaluation of lift. The internal aerodynamics study will be limited to ram air to the intake, heat exchanger, and oil cooler.

Aerodynamic drag is the force that restricts the forward velocity of a vehicle. Sources of drag are form drag, interference drag, internal flow drag, surface friction, and induced drag. Aerodynamic drag directly impacts the fuel economy attainable by a vehicle. In the Formula SAE competition (FSAE), fuel economy is a factor during the endurance phase. This paper will focus on the effects of aerodynamic drag and how it impacts the fuel economy of a FSAE racing style vehicle. Using the Lawrence Technological University (LTU) 1999 and 2000 cars to study and evaluate various methods to reduce drag and optimize fuel economy. Theoretical and experimental methods will be used and the study will be limited to the effects of form and interference drag.

This paper discusses how to effectively design and set-up an ideal spring/damper combination in a low-mass open wheeled racecar to properly control vehicle handling and gain optimum performance of the system. The system that will be discussed is outfitted with a non-parallel, unequal length SLA suspension that was designed and raced at the 2001 Formula SAE competition. The focus of this paper will be more on how to choose an ideal suspension set-up for a low-mass open wheeled racecar, while considering the various variables that can affect the system as a whole. To properly design a suspension, a passive system will be used, and then the performance gains of a semi-active system will be introduced and discussed.

This paper is an introduction to the design of suspension components for a Formula SAE car. Formula SAE is a student competition where college students conceive, design, fabricate, and compete with a small formula-style open wheel racing car. The suspension components covered in this paper include control arms, uprights, spindles, hubs, pullrods, and rockers. Key parameters in the design of these suspension components are safety, durability and weight. The 2001 Lawrence Technological University Formula SAE car will be used as an example throughout this paper.

This paper reviews how sound transmission loss (STL) of insulators is affected by gravitational and thermal effects. A special STL test fixture was designed and fabricated to quickly and accurately obtain the STL measurement of a sample oriented at various controlled angles. The STL apparatus was designed to roll into a large reverberation chamber and act as the anechoic termination for a two-microphone approach to measuring STL. The fixture was also built with the intention of studying the temperature effects on a material's STL performance. A variety of samples, including lightweight and traditional barrier decoupled insulators, were tested in the horizontal, vertical, and inverted positions to evaluate gravitational/inertial effects. Thermal effects were investigated by bringing the STL apparatus and sample to a low temperature by moving outdoors, and then rolling the system into the reverberation chamber, at normal room temperature.

There is evidence to suggest that before military equipment ever experiences sustainment delays the equipment carries state patterns within its logistics and supply chain data history that could be leveraged for risk mitigation. Analysis of these patterns can also identify new research & development (R&D) and technology transition candidates that relate the seemingly disparate activities of R&D project management and Diminishing Manufacturing Sources and Material Shortages (DMSMS) management. Relating eligible R&D activities to the DMSMS risk identification phase helps stage potential sustainment risk mitigations ahead of time on the one hand, while creating additional demand and resources to mature prototypes on the other hand.

This paper presents an experimental investigation of flow field instabilities in a centrifugal pump impeller at low flow rates. The measurements of pump hydraulic performance and flow field in the impeller passages were made with a hydraulic test rig. Analysis of Q-ΔP-η data and flow structures in the impeller passages were performed. In the present work, the effect of various flowrates on centrifugal pump impeller performance was analyzed based on pump measured parameters. The impeller’s geometry was modified, with positioning the curved spacer at the impeller suction side. This research investigates the effect of each inlet curved spacer model on pump performance improvement. The hydraulic performance and cavitation performance of the pump have been tested experimentally. The flow field inside a centrifugal pump is known to be fully turbulent, three dimensional and unsteady with recirculation flows and separation at its inlet and exit.

The dynamics of an AWD vehicle is determined by the interactions between the vehicle's wheels and the tire contact surface. Understanding and controlling these interactions drives the vehicle mobility and energy efficiency. In this paper new issues related to tire slippage control are addressed. The paper analytically demonstrates that two tires on the same axle with the same rotational speeds can have different slippages when the normal reaction and inflation pressure vary due to motion conditions. Hence, a new method is proposed to control the rotational velocity of the wheels in a way that provides the same slippages of the tires by accounting for changes in the normal load and tire inflation pressure. This approach is especially beneficial for vehicles with individual (electric) wheel drives which can be individually controlled by introducing the proposed algorithm for controlling both the vehicle linear velocity and the tire slippages.

In this study, a new nonlinear correlation between Brinell hardness and ultimate tensile strength is proposed. The correlation factor in this case is higher than that found in the current literature. The ultimate tensile strength is replaced by an equivalent hardness expression in the Modified Universal Slopes Method. This change results in fatigue parameters that are predicted using hardness, true fracture ductility, and modulus of elasticity. This new fatigue life prediction approach is compared with the original Modified Universal Slopes method and experimental data in literature. This method is valid for steel with hardness that ranges from 150HB to 660HB. The results show that this method provides better approximations of the strain-life curves when compared with the Modified Universal Slopes and experimental data.

To evaluate traction and velocity performance and other operational properties of a vehicle requires data on some tire parameters including the effective rolling radius in the driven mode (no torque on a wheel), the effective radii in the drive mode (torque applied to the wheel), and also the tire longitudinal elasticity. When one evaluates vehicle performance, these parameters are extremely important for linking kinematic parameters (linear velocity and tire slip coefficient) with dynamic parameters (torque and traction net force) of a tired wheel. This paper presents an experimental method to determine the above tire parameters in laboratory facilities. The facilities include Lawrence Technological University's 4x4 vehicle dynamometer with individual control of each of the four wheels, Kistler RoaDyn® wheel force sensors that can measure three forces and three moments on a wheel, and a modern data acquisition system. The experimental data are also presented in the paper.

Today's strict fuel economy requirement produces the need for the cars to have really optimized shapes among other characteristics as optimized cooling packages, reduced weight, to name a few. With the advances in automotive technology, tight global oil resources, lightweight automotive design process becomes a problem deserving important consideration. It is not however always clear how to modify the shape of the exterior of a car in order to minimize its aerodynamic resistance. Air motion is complex and operates differently at different weather conditions. Air motion around a vehicle has been studied quite exhaustively, but due to immense complex nature of air flow, which differs with different velocity, the nature of air, direction of flow et cetera, there is no complete study of aerodynamic analysis for a car. Something always can be done to further optimize the air flow around a car body.

The 1999 Lawrence Technological University (LTU) drive train consists of a sprocket and chain assembly that delivers the torque, developed by a 600cc Honda F3 engine, to the rear wheels. The torque is transferred through a limited-slip, torque sensing differential unit comprised of a gear set in a student designed housing. The 1999 differential is a second-generation aluminum housing. The idea of using aluminum was first attempted with the 1998 team who successfully completed and used aluminum despite much complexity and a few design flaws. Therefore, in the LTU Formula Team's continuing effort to optimize the design, a new less complex design was conceived to house the gear set. This innovative design reduces the number of housing components from three in 1998, to two in 1999.

An ergonomics apparatus was designed and built to aid in the design of a Formula SAE (FSAE) Race Car cockpit. The apparatus incorporated adjustable cockpit dimensions that were adjusted accordingly for the tested subjects. A compilation of this data was used to design a cockpit suitable for people within the range of 95th percentile male and 5th percentile female. By testing subjects in various cockpit designs, the ergonomics apparatus was also used to validate the final design of the cockpit.

Traction control is an electronic means of reducing the wheel spin caused by the application of excessive power for the valuable grip. Wheel spin can result in loss control of the car, reduce acceleration and cause tire wear. In the front wheel tire the loss grip is experienced as underwater, where the front of the car ‘pushes’ forward, not turning as much as the driver has exposed by turning the tearing. In the rear wheels slip causing oversteer, where the rear of the car swings around, turning much sharper than the driver anticipated. The result of all these problems is that the driver starts loosing control of the vehicle, which is undesirable. With the new design of the Traction Control System, the amount of the wheel slippage is precisely controlled. In racing, this means corner can be taken constantly quicker, with system applying the maximum power possible while the driver remains in total control.