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A new technique for measuring the friction coefficient between the punch and workpiece during sheet forming operations has been developed at the Ohio State University. Various materials, such as interstitial-free (IF) steel, high strength (HS) steel, an aluminum alloy (2008T4) and 70/30 brass, were tested under dry and oil lubrication conditions at different punch rates and process conditions. The results show that punch friction depends on the angle of wrap, which varies with punch stroke, and on the strain rate, which depends on punch velocity. The O.S.U. Friction Test is described and typical results are presented which verify the usefulness of the new procedure.

This paper presents an overview of the evolution of computer simulations in vehicle collision and occupant kinematic reconstructions. The basic principles behind these simulations, the origin of these programs and the evolution of these programs from a basic analytical mathematical model to a sophisticated computer program are discussed. In addition, a brief computer development history is discussed to demonstrate how the evolution of computer assisted vehicle accident reconstruction becomes feasible for a reconstructionist. Possible future research in computer reconstruction is also discussed.

A distributed parameter mathematical model of a complete power steering hydraulic transmission circuit has been developed and implemented on a personal computer to analyze the effect of tuning cables on the attenuation of pressure waves generated by the pump. Tuning cables, flexible tubes positioned coaxially inside a length of hose placed at a convenient location in the circuit, reduce fluidborne noise primarily by destructive interference and viscous damping. The model uses a transfer matrix approach that includes two-dimensional viscous flow and three-dimensional fluid-structure interaction. It can be used for sizing and positioning tuning cable devices in power steering as well as other hydraulic systems prior to verification testing of the circuit.

A newly developed process allows the near-net shape fabrication of alumina/aluminum composite bodies via the immersion of a sacrificial oxide preform into a molten aluminum alloy bath. The resulting composite possesses an attractive range of properties for application in several automotive components. These properties include: high strength and stiffness, appreciable thermal and electrical conductivity, high strength at elevated temperatures, coefficient of thermal expansion of 10 X 10-6 C-1 and relative ease of machinability. Low cost fabrication renders this material/process ideal for components such as brake rotors and calipers, cylinder bore liners, piston components.

The process of producing co-continuous ceramic composite material has been investigated in order to provide a greater understanding of the formation mechanism and hence evaluate the viability of commercial applications for these exciting new materials. The ease of manufacture for components combined with the low production cost hold great promise for the production of brake rotors, brake calipers, piston crowns, cylinder liners, gears and turbine compressors. Practical issues such as bonding to this material, together with the machinability have been addressed, our findings are presented in this paper.

This paper describes the development and experimental validation of a Plug-in Hybrid Electric Vehicle (PHEV) dynamic simulator that enables development, testing, and calibration of a traction control strategy. EcoCAR 2 is a three-year competition between fifteen North American universities, sponsored by the Department of Energy and General Motors that challenges students to redesign a Chevrolet Malibu to have increased fuel economy and decreased emissions while maintaining safety, performance, and consumer acceptability. The dynamic model is developed specifically for the Ohio State University EcoCAR 2 Team vehicle with a series-parallel PHEV architecture. This architecture features, in the front of the vehicle, an ICE separated from an automated manual transmission with a clutch as well as an electric machine coupled via a belt directly to the input of the transmission. The rear powertrain features another electric machine coupled to a fixed ratio gearbox connected to the wheels.

For some vehicle dynamics applications, an estimate of a vehicle's center of gravity (cg) height and mass moments of inertia can suffice. For other applications, such as vehicle models and simulations used for vehicle development, these values should be as accurate as possible. This paper presents several topics related to inertial parameter estimation and measurement. The first is a simple but reliable method of estimating vehicle mass moment of inertia values from data such as the center of gravity height, roof height, track width, and other easily measurable values of any light road vehicle. The second is an error analysis showing the effect, during a simple static cg height test, of vehicle motion (relative to the support system) on the vehicle's calculated cg height. A method of accounting for this motion is presented. Similarly, the effects of vehicle motion are analyzed for subsequent mass moment of inertia tests.

In sheet metal forming, drawbeads are often used to control uneven material flow which may cause defects such as wrinkles, fractures, surface distortion and springback. Appropriate setting and adjusting the drawbead force is one of the most important parameters in sheet forming process control. However, drawbead design and drawbead force adjustment still rely on trial-and-error procedures. This paper summarizes the guidelines in drawbead design, evaluates a number of mathematical models in estimating drawbead forces, and investigates the effects of sheet thickness, material properties, drawbead geometry and penetration on the drawbead force.

Predominant failure modes in the forming of sheet metal parts are wrinkling and tearing. Wrinkling may occur at the flange as well as in other areas of the drawn part and is generated by excessive compressive stresses that cause the sheet to buckle locally. Fracture occurs in a drawn material which is under excessive tensile stresses. For a given part and blank geometries, the major factors affecting the occurrence of defects in sheet metal parts are the blank holder force (BHF) and the blank holder pressure (BHP). These variables can be controlled to delay or completely eliminate wrinkling and fracture. Modern mechanical presses are equipped with hydraulic cushions and various advanced multi-point pressure control systems. Thus, the BHP can be adjusted over the periphery of the blank holder as a function of location and time (or press stroke).

Shrink flanging is a major sheet forming operation to produce convex flanges in structural sheet metal components. Flanges are used for appearance, rigidity, hidden joints, and strengthening of the edge of sheet parts such as automobile front fender and complex panels formed by stretch/draw forming. Wrinkling around the flange edge is the major defect in shrink flanging operation. There has been a lack of reliable mathematical modeling to predict the strains and wrinkles in shrink flanging operations. A trial-and-error approach has been usually practiced in tooling and process designs. In this paper, a wrinkling criterion in shrink flange is proposed based on a simplification from a general criterion for a doubly curved anisotropic shell. The mathematical model for strain analysis in shrink flanging is established based on Wang and Wenner's strain model for stretch flange. Shrink flanging experiments were conducted to validate the theories.

This paper describes the background and development of a program focused on motorsports engineering education currently in progress at the Ohio State University (OSU). An interdisciplinary curriculum, with the involvement of various engineering departments, is being proposed for development in an attempt to address some of the engineering education needs of the motorsports industry. The program described in this paper strives to provide engineering students with an interdisciplinary background race engineering, and also provides opportunities for motorsports oriented thesis projects. The paper briefly summarizes the key elements of the curriculum, and describes how the integration of course material from different disciplines with team work on student competition projects, possibly coupled with internships with racing teams, can provide an ideal setting for the education of a new generation of race engineers.

Plane strain bending (e.g. bending about a straight line) is a major sheet forming operation and it is practiced as brake bending (air bending, U-die, V-die and wiping-die bending). Precise prediction of springback is the key to the design of the bending dies and to the control of the process and press brake to obtain close tolerances in bent parts. In this paper, reliable mathematical models for press brake bending are presented. These models can predict springback, bendability, strain and stress distributions, and the maximum loads on the punch and die. The elasto-plastic bending model incorporates the true (nonlinear) strain distribution across the sheet thickness, Swift's strain hardening law, Hill's 1979 nonquadratic yield criterion for normal anisotropic materials, and plane strain deformation mode.

A computer simulation has been developed that models conventional, electric, and hybrid drivetrains. The vehicle's performance is predicted for a given driving cycle, such as the Federal Urban Driving Schedule (FUDS). This computer simulation was used in a massive designspace exploration to simulate 1.8 million different vehicles, including conventional, electric, and hybrid-electric vehicles (HEVs). This paper gives a description of the vehicle simulator as well as the results and implications of the large design-space exploration.