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A finite element (FE) model with knee-thigh-hip (KTH) and lower-extremity muscles has been developed to study the potential effects of muscle tension on KTH injuries due to knee bolster loadings in frontal crashes. This model was created by remeshing the MADYMO human lower-extremity FE model to account for regional differences in cortical bone thickness, trabecular bone, cortical bone with directionally dependent mechanical properties and Tsai-Wu failure criteria, and articular cartilage. The model includes 35 Hill-type muscles in each lower extremity with masses based on muscle volume. The skeletal response of the model was validated by simulating biomechanical tests without muscle tension, including cadaver skeletal segment impact tests documented in the literature as well as recent tests of seated whole cadavers that were impacted using knee-loading conditions similar to those produced in FMVSS 208 testing.

The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situations including the worst cases such as rollover, spin-out and so on. Although the known NHTSA J-turn and Fish-hook steering maneuvers are applied for the vehicle performance assessment, they are not enough to predict other possible worst case scenarios. Therefore, it is crucial to search for the various worst cases including the existing severe steering maneuvers. This paper includes the procedure to search for other useful worst case based upon the existing worst case scenarios in terms of rollover and its application in simulation basis. The human steering angle is selected as a design variable and optimized to maximize the index function to be expressed in terms of vehicle roll angle. The obtained scenarios were enough to generate the worse cases than NHTSA ones.

A multi-body dynamics model of the U.S. Army3s High Mobility Multi-purpose Wheeled Vehicle (HMMWV) has been created using commercial software (ADAMS) to simulate and analyze the vehicle3s rollover behavior. However, manual operation of such simulation and analysis for design purposes is prohibitively expensive and time consuming, limiting the engineers3 ability to utilize the model fully and extract from it useful design information in a timely, cost-effective manner. To address this challenge, a commercial system integration and optimization software (OPTIMUS) is utilized in order to automate the simulation processes and to enable the more complex uncertainty-based analysis of the HMMWV rollover behavior under a variety of external conditions. Challenges involved in integrating the software are highlighted and remedies are discussed. Rollover analysis results from using the integrated model and automated simulation are also presented.

Half of the car occupant deaths involved in two-vehicle crashes results from side impact collisions. In an attempt to better understand the role that vehicle mass plays in crashes and injury causation, detailed information from the NASS CDS database on injury source was distributed in three classes: contact with intrusion, contact without intrusion, and restrained acceleration or non-contact. We compared these distributions for belted drivers in side verses frontal crashes. When looking at the type of striking, or bullet, vehicle in near-side impacts, we found that intrusion injuries are more prevalent in cars hit by SUVs and pickups than by other cars. We also looked at the body region injured verses the type of striking vehicle and found head injuries to be slightly more prevalent when the striking vehicle is an SUV or pick-up. Data from the University of Michigan CIREN case studies on side impacts are presented and are consistent with the NASS CDS data.

Automated clutches for vehicle startup is being increasingly deployed in commercial trucks for benefits, which include driver comfort, gradient performance, improved clutch life, emissions and driveline vibration reduction potential. The process of designing the controller is divided into 2 parts. Firstly, the parameter estimation of previously developed driveline models is carried out. The procedure involves an off-line minimization technique based on measured and estimated speeds. Secondly, the nominal plant model is used to develop LQR based optimal control strategy, which takes into account the slip time, dissipated power and slip acceleration. Mathematical expression of the performance index is clearly developed. A variety of clutch lock up profiles can be incorporated by changing a single tuning parameter, thus providing the driver the ability to select a launch profile based on specific driving objectives.

The Milliken Moment Method (MMM) can be used to quantify the constraints imposed on vehicle stability and controllability by front and rear tire traction limitations. The main aspect of the Milliken Moment Method is the plot of vehicle's yaw moment versus lateral acceleration for given vehicle sideslip and steering angle ranges. This plot is typically called the Milliken Moment Diagram (MMD). This paper proposes a dynamic simulation approach to implementing the MMM that emulates the traditional experimental one. The approach embeds a vehicle dynamics model in a control loop that maintains a constant desired sideslip angle, and integrates the resulting controlled vehicle system model in time to generate the MMD.

In this paper, a simulation-based dynamic rollover evaluation procedure is described. This work is based on the worst-case methodology developed at the University of Michigan, and is the result of a collaborated research project between the University of Michigan and TRW Inc. The target vehicle studied in this paper is a large production volume SUV. This vehicle is equipped with a production-intent TRW Vehicle Stability Control (VSC) system. The main goals of this paper are to (i) study the rollover propensity of this SUV, as influenced by vehicle and environment parameters such as vehicle speed, road condition, etc.; and (ii) investigate whether, and by how much, does the VSC system influence the rollover propensity of this SUV. The modeling, evaluation procedure, and preliminary evaluation results are reported.

The addition of synthetic traffic to a driving simulation greatly enhances the realism of the virtual world. Giving this traffic human-like behavior is likewise desirable, and has been the focus of some research over the past few years. This paper presents a modular architecture for including autonomous traffic in a driving simulation, and describes the first steps taken toward the application of this architecture to the DaimlerChrysler Auburn Hills Simulator. By separating the planning part of the agent from the low-level control and vehicle dynamics systems, the described architecture permits the inclusion of powerful, previously developed components in a straightforward way; in the present application, agents use Soar to reason about their actions. This paper gives an overview of the structures of the agents, and of the entire system, describes the components and their implementations, and discusses the current state of the project and plans for the future.

Belt drives have long been utilized in engine applications to power accessories such as alternators, pumps, compressors and fans. The first belt drives consisted of one or more V-belts powering fixed-centered pulleys and were pre-tensioned by statically adjusting the pulley center separation distances. In recent years, such drives have been replaced by a single, flat, ‘serpentine belt’ tensioned by an ‘automatic tensioner.’ The automatic tensioner consists of a spring-loaded, dry friction damped, tensioner arm that contacts the belt through an idler pulley. The tensioner's major function is to maintain constant belt tension in the presence of changing engine speeds and accessory loads. The engine crankshaft supplies both the requisite power to drive the accessories as well as the (unwanted) dynamic excitation that can adversely affect the accessories and the noise and vibration performance of the belt.

Real-time simulation of tracked vehicle dynamics demands very efficient modeling of the vehicle track. Multi-body dynamics models which model the response of each track pitch are complete, but require on the order of 100 degrees of freedom to capture lateral track dynamics and an additional 200 degrees of freedom to capture longitudinal (stretching) track dynamics. The sheer size of such models renders them difficult to use for rapid estimates of track response. This paper summarizes an efficient alternative for modeling vehicle tracks, as illustrated herein by a model for longitudinal track dynamics. The present model is a hybrid discrete/continuous model in which the track is modeled as a continuous uniform elastic rod which is kinematically coupled to discrete models for the sprocket, wheels, and rollers. Solution efficiency derives from transforming the dynamic track model to one employing modal coordinates.

Using the CDC (SAE J224), a comparison of the NASS data and the UMTRI field accident files (UM series) indicates a similar distribution of offset frontal crashes. Offset frontal damage occurs in 56-61% of crashes, often involving more than one third of the front of the car. Lap-shoulder belted drivers sustain more AIS 2 or greater injuries when there is interior intrusion and occur more often when the offset damage is in front of the driver. However, this may well be due to the severity of the crash. European studies have no uniformity as to offset frontal collision descriptors are difficult to interpret, or to compare one to another.

The preliminary design of a single engine business jet is presented. The airplane is intended to fill a market niche surrounded by several types of airplanes: single engine (piston and turboprop) and entry-level twin engine airplanes (turboprop and turbofan). The Williams-Rolls FJ44 turbofan engine, with a takeoff thrust rating of 1900 pounds, is chosen as the powerplant because of its low acquisition and maintenance costs. The airplane is designed to carry four persons and baggage 1500 n.m. with VFR reserves, and is intended to meet FAR 23 standards — including the 61 knot single engine stall speed requirement. A parametric analysis of wing aspect ratio, thickness, and taper is performed to determine the best planform from the standpoint of weight, cruise speed, and cost. Maximum cruise speed is estimated to be 371 knots and the airplane purchase price is estimated to be 1.98 million. These results indicate the airplane will satisfy intended market niche.

NASS 80-88 passenger side impacts data were analyzed. Location of primary car damage using the CDC classification, the AIS for injury severity studies, and the interior contacts of the various body areas. Drivers alone, or with passengers were studied separately in both left and right side crashes. Direct impacts to the passenger compartment only are less frequent than to other CDC side zones. Driver interior contacts vary by body region but also by side impacted in the crash. The presence of an unrestrained front passenger appears to enhance driver injury level in left side crashes but the presence of a passenger, in right side crashes appears to moderate driver injury severity.

A method has been developed for calculating the internal temperature distribution in an aircraft tire while free rolling under load. The method uses an approximate stress analysis of each point in the tire as it rolls through the contact patch, and from this stress change the mechanical work done on each volume element may be obtained and converted into a heat release rate through a knowledge of material characteristics. The tire cross-section is then considered as a body with internal heat generation, and the diffusion equation is solved numerically with appropriate boundary conditions at the wheel and runway surface. Comparisons with buried thermocouples in actual aircraft tires shows good agreement.

Lap-shoulder belt effectiveness has been indicated by many authors, however there is minimal information on the more severe injuries to lap-shoulder belted car occupants. This paper presents details of 15 lap-shoulder belted occupants in frontal collisions and 24 lap-shoulder belted occupants in side impact collisions. Case descriptions of these crashes are presented, each including vehicle, environmental and injury details.

Although over 800 references to child and infant anthropometry are in the literature, most have limited validity and application to current populations. Functional measures required by industry and government for federal safety standards for design of dummies, child products, furniture, or protective devices such as restraint systems have either been incomplete, inadequate, or nonexistent. Some of the limitations influencing validity of existing data have been outlined for the potential user. As a start toward obtaining necessary functional anthropometric data, The University of Michigan is currently conducting a study sponsored by the U.S. Consumer Product Safety Commission to obtain valid nationwide measurements on a representative U.S. population from birth to age 12 years. In this study some 41 measurements, including many functional measures, as well as seated and supine whole-body centers of gravity, are being taken utilizing a new automated anthropometric minicomputer system.