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The Sine with Dwell (SWD) maneuver is the basis for the NHTSA FMVSS-126 regulation. When put into effect, all vehicles under 10,000 lbs GVWR will need to pass this test. Understanding the variability in the yaw rate ratio and lateral displacement test metrics is important for vehicle design. Anything that influences vehicle handling can affect test metric variability. Vehicle handling performance depends largely on vertical tire patch loads, tire force and moment behavior, on slip angle, and camber angle. Tire patch loads are influenced, among other things, by weight distribution and (quasi-static and dynamic) roll-couple distribution. Tire force and moment relationships have a distinct shapes, but they all commonly rise to a peak value at a given slip angle value and then fall off with increasing slip angle. Severe handling maneuvers, like the SWD operate at slip angles that are at, or above, the peak lateral force.

The goal of this paper is to discuss the critical aspects of damper tuning for production vehicles. These aspects include ride and handling performance attributes, damper basics, conflicts in achieving desirable results, tuning philosophies, and the influence of the damper design. The marketplace has become increasingly competitive. Customer preference, cost, mass and regulatory pressures often conflict. Yet each year more vehicles are required to do all these things well. Damper tuning can play a significant role in resolving these conflicts. Although many papers have been written on the theory behind damper design and capabilities, there has been very little written about the techniques of tuning dampers for production vehicles. This paper attempts to discuss the critical aspects of damper tuning for production vehicles in four sections. The first section discusses the performance attributes of ride and handling. The second section provides a basic understanding of dampers.

The automotive industry commonly uses two definitions of the suspension roll center, the Kinematic Roll Center (KRC) - of interest in studying suspension geometry, and the Force-based Roll Center (FRC) - of interest in studying steady-state vehicle dynamics. This paper introduces a third definition, the Dynamic Roll Axis (DRA) - of interest in studying transient vehicle dynamics. The location of each one of these roll centers has a unique application to vehicle design and development. Although the physical meaning of each roll center is significantly different, the generic term “roll center” is often used without proper specification. This can lead to confusion about how roll centers influence vehicle behavior.

Under the initiative of The United States Council for Automotive Research LLC (USCAR) [1], we have developed and run comprehensive friction tests of dual clutch transmission fluids (DCTFs). The focus of this study is to quantify the anti-shudder durability over a simulated oil life of 75,000 shifts. We have evaluated six DCT fluids, including 2 fluids with known field shudder performance. Six different tests were conducted using a DC motor-driven friction test machine (GK test bench): 1. Force Controlled Continuous Slip, 2. Dynamic Friction, 3. Speed controlled Acceleration-Deceleration, 4. Motor-torque controlled Acceleration-Deceleration, 5. Static Friction, and 6. Static Break-Away. The test fluids were aged (with the clutch system) on the test bench to create a realistic aging of the entire friction system simultaneously.

Heat treated cast aluminum components like engine blocks and cylinder heads can develop significant amount of residual stress and distortion particularly with water quench. To incorporate the influence of residual stress and distortion in cast aluminum product design, a rapid simulation approach has been developed based on artificial neural network and component geometry characteristics. Multilayer feed-forward artificial neural network (ANN) models were trained and verified using FEA residual stress and distortion predictions together with part geometry information such as curvature, maximum dihedral angle, topologic features including node's neighbors, as well as quench parameters like quench temperature and quench media.

For a CAE model of the park pawl dynamic system, the engagement speed calculation is done by controlling the input rotational velocity of the vehicle. Usually, it requires multiple adjustment of the input rotational velocity to get the engagement speed and that demands time, effort and file management skill of an analyst. The current objective of this paper is to demonstrate how software Isight, working with ABAQUS Explicit as the solver, can be used to automate the engagement speed calculation procedure and thus reduce the time and effort required of a CAE analyst. The automated system is developed in a way such that the accuracy of the results can be controlled by the end user. It is observed that the automated system significantly saves an analyst's effort. The system design can be optimized easily for modifiable design features such as the torsional spring and the actuator spring stiffness values using the proposed procedure.

Rapidly increasing customer, financial, and regulatory pressures are creating clear changes in the calculus of vehicle design for modern automotive OEM's (Original Equipment Manufacturers). Customers continue to demand shorter product lifecycles; the increasingly competitive global market exerts pressure to reduce costs in all stages of development; and environmental regulations drive a continuous need to reduce mass and energy consumption. OEM's must confront these challenges while continuing to satisfy the customer. The foundation to meeting these challenges includes: (1) Continued development of objective metrics to quantify performance; (2) Frontloading vehicle design content and performance synthesis; (3) A precise understanding of the customer and their performance preferences under diverse usage conditions. These combined elements will enable products better optimized amongst competing (and often contradictory) imperatives.

This paper presents an overview of a four-year project focused on development of an integrated computational materials engineering (ICME) toolset for third generation advanced high-strength steels (3GAHSS). Following a brief look at ICME as an emerging discipline within the Materials Genome Initiative, technical tasks in the ICME project will be discussed. Specific aims of the individual tasks are multi-scale, microstructure-based material model development using state-of-the-art computational and experimental techniques, forming, toolset assembly, design optimization, integration and technical cost modeling. The integrated approach is initially illustrated using a 980MPa grade transformation induced plasticity (TRIP) steel, subject to a two-step quenching and partitioning (Q&P) heat treatment, as an example.

Impact toughness (or resistance to fracture) is a key material property for press hardened steel used in construction of the safety-critical elements of automotive body structures. Prior austenite grain size, as primarily controlled by the incoming microstructure and austenitization process, is a key microstructural feature that influences the impact toughness of press hardened steel. In this paper, a special Charpy V-notch impact test is developed to quantify the impact toughness of press hardened steel sheets with various prior austenite grain sizes, by stacking a number of thin sheets via mechanical riveting. Both the ductile-to-brittle transition temperature and upper shelf energy are analyzed in an effort to establish a correlation between impact toughness and prior austenite grain size. Within tested conditions, impact performance shows only a slight decrease as the prior austenitic grain size increases from 18 to 38 microns.

AZ31B Mg sheet is being considered for automotive applications. This study investigates the effect of pre-treatments, such as heat-treatments and surface treatments, on the corrosion performance of AZ31B sheet, with a goal of learning which pre-treatment can improve corrosion resistance of the sheet material in production. It is found that the heat-treatment and oxidation during a warm and hot forming (WHF) process will not deteriorate the corrosion performance of the AZ31B sheet; polishing and acid etching can clean the surface and significantly increase the corrosion resistance, but corrosion can be accelerated by sandblasting which contaminates the surface. The change in corrosion performance can be associated with surface cleaning or contamination of the sheet by these pre-treatments. Furthermore, the influence of a pre-treatment on the uncoated AZ31B sheet may affect its corrosion behavior after coating.

The strain-induced diffusionless shear transformation of retained austenite to martensite during straining of transformation induced plasticity (TRIP) assisted steels increases strain hardening and delays necking and fracture leading to exceptional ductility and strength, which are attractive for automotive applications. A novel technique that provides the retained austenite volume fraction variation with strain with improved precision is presented. Digital images of the gauge section of tensile specimens were first recorded up to selected plastic strains with a stereo digital image correlation (DIC) system. The austenite volume fraction was measured by synchrotron X-ray diffraction from small squares cut from the gage section. Strain fields in the squares were then computed by localizing the strain measurement to the corresponding region of a given square during DIC post-processing of the images recorded during tensile testing.