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Recent field data studies have shown that force-limiting belt systems reduce the occurrence of thoracic injuries in frontal crashes relative to standard (not force-limiting) belt systems. Laboratory cadaver tests have also shown reductions in trauma, as well as in chest deflection, associated with a force-limiting belt. On the other hand, tests using anthropomorphic test devices (ATDs) have shown trends indicating increased, decreased, or unchanged chest deflection. This paper attempts to resolve previous experimental studies by comparing the anterior-posterior and lateral chest deflections measured by the THOR and Hybrid III (H-III) dummies over a range of experimental conditions. The analysis involves nineteen 48-km/h and 57-km/h sled tests utilizing force-limiting and standard seat belt systems, both with an air bag. Tests on both the driver side and the passenger side are considered.

An On-Board Distillation System (OBDS) was developed to extract, from gasoline, a highly volatile crank fuel that allows the reduction of startup fuel enrichment and significant spark retard during cold starts and warm-up. This OBDS was installed on a 2001 Lincoln Navigator to explore the emissions reductions possible on a large vehicle with a large-displacement engine. The fuel and spark calibration of the PCM were modified to exploit the benefits of the OBDS startup fuel. Three series of tests were performed: (1) measurement of the OBDS fuel composition and distillation curve per ASTM D86, (2) measurement of real-time cold start (20 °C) tailpipe hydrocarbon emissions for the first 20 seconds of engine operation, and (3) FTP drive cycles at 20 °C with engine-out and tailpipe emissions of gas-phase species measured each second. Baseline tests were performed using stock PCM calibrations and certification gasoline.

Since the market for continuously variable transmissions (CVTs) is expanding rapidly and customer demands become more and more specific, there is an increasing need for adequate CVT fluids. In order to develop and apply new fluids, it is necessary to have reliable methods for fluid testing. However, test methods and standards that are being used nowadays for automatic transmission applications are not sufficient to select fluids for push belt CVT applications since they do not incorporate the belt-pulley behaviour. In this paper a method is described to test fluids on a belt-pulley level. The test method comprises full load testing in several ratios in which durability and functionality related push belt CVT items are being examined. This Van Doorne CVT Fluid Test can be used in addition to existing fluid tests in order to determine the suitability of fluids for push belt CVT applications.

Little is known about the response of the shoulder complex due to lateral and oblique loading. Increasing this knowledge of shoulder response due to these types of loading could aid in improving the biofidelity of the shoulder mechanisms of anthropomorphic test devices (ATDs). The first objective of this study was to define force versus deflection corridors for the shoulder corresponding to both lateral and oblique loading. A second focus of the shoulder research was to study the differences in potential injury between oblique and lateral loading. These objectives were carried out by combining previously published lateral impact data from 24 tests along with 14 additional recently completed lateral and oblique tests. The newly completed tests utilized a pneumatic ram to impact the shoulder of approximately fiftieth percentile sized cadavers at the level of the glenohumeral joint with a constant speed of approximately 4.4 m/sec.

Forty-two side impact cadaver sled tests were conducted at 24 and 32 km/h impact speeds into rigid and padded walls. The post-mortem human subjects were instrumented with accelerometers on the ribs and spine and chest bands around the thorax and abdomen to characterize their mechanical response during the impact. Load cells at the wall measured the impact force at the level of the thorax, abdomen, pelvis, and lower extremities. The resulting injuries were determined through detailed autopsy and radiography. Rib fractures with or without associated hemo/pneumo thorax or flail chest were the most common injury with severity ranging from AIS=0 to 5. Full and half thorax deflections were computed from the chest band data. The cadaver test data was analyzed using ANOVA and logistic regression. The age of the subject at the time of death had influence on injury outcome while gender and mass of the subject had little or no influence on injury outcome.

As more and more active restraint devices are added by vehicle manufacturers for occupant protection, the history of driver frontal airbags illustrates that the design performance of such devices for in-position (IP) occupants often have to be limited in order to reduce their aggressiveness for out-of-position (OOP) situations. As of today, a limited number of publications dealing with FE simulation of airbag deployment for OOP are available. The objective of our study was to evaluate the feasibility of airbag deployment simulations based on an extensive set of well-defined physical test matrix. A driver frontal airbag was chosen (European mid-size car sample) for this study. It was deployed against a force plate (14 tests in a total of 6 configurations), and used with Hybrid III 50th percentile dummy (HIII) in OOP tests (6 tests, 4 configurations). Special attention was paid to control the boundary conditions used in experiments in order to improve the modelling process.

In 1983, General Motors Corporation (GM) petitioned the National Highway Traffic Safety Administration (NHTSA) to allow the use of the biofidelic Hybrid III midsize adult male dummy as an alternate test device for FMVSS 208 compliance testing of frontal impact, passive restraint systems. To support their petition, GM made public to the international automotive community the limit values that they imposed on the Hybrid III measurements, which were called Injury Assessment Reference Values (IARVs). During the past 20 years, these IARVs have been updated based on relevant biomechanical studies that have been published and scaled to provide IARVs for the Hybrid III and CRABI families of frontal impact dummies. Limit values have also been developed for the biofidelic side impact dummies, BioSID, EuroSID2 and SID-IIs.

A non-linear contact analysis of a leading-trailing shoe drum brake, using the finite element method, is presented. The FE model accurately captures both the static and pseudo-dynamic behaviour at the friction interface. Flexible-to-flexible contact surfaces with elastic friction capabilities are used to determine the pressure distribution. Static contact conditions are established by initially pressing the shoes against the drum. This first load step is followed by a gradual increase of applied rotation to the drum in order to define the maximum reacted braking torque and pseudo-dynamic pressure distribution at the transition point between sticking and sliding motion. The method clearly illustrates the changes in contact force that take place as a function of the applied pressure, coefficient of friction and initial gap between lining and rotor. These changes in contact area are shown to influence the overall stability and therefore squeal propensity of the brake assembly.

The direct finite element analysis (FEA) approach for disc brake squeal prediction is presented in this paper. A linear model is developed to include the impact of negative μ-v slope on brake systems noise performance. The recently-developed iterative algorithm - ABLE, is used to solve the resulting large-scale complex eigenvalue problems on a PC. Efficiency and effectiveness of the algorithm are discussed. Good correlations are achieved between simulation and measurement, both in squeal frequencies and corresponding unstable modal shapes. Initial study has also validated the conventional wisdom that negative μ-v slope can cause more system instabilities.

This paper presents a new functionality of ABAQUS/Standard, which allows for a nonlinear analysis prior to a complex eigenvalue extraction in order to study the stability of brake systems. Friction-induced dynamic instabilities are caused mainly by two phenomena: coupling of two neighboring modes and negative friction-velocity gradient. Both of these phenomena can be modeled with ABAQUS. A simplified brake model, consisting of only a rotor and pads, is used to illustrate this new capability.

The out-of-plane vibration characteristics of a noisy brake are generally better understood than in-plane characteristics. The fundamental reason for this is that in-plane vibration was not considered a significant effect until recently when technology has allowed the in-plane vibration characteristics to be determined with some degree of confidence. Detailed investigations of the side views of out-of-plane holographic images indicated that the in-plane displacement could be quite significant and possibly larger than the out-of-plane displacement. It was because the fringe pattern could not be attributed solely to out-of-plane displacement that a study of in-plane vibration was initiated. The paper discusses the measurement of both out-of-plane and in-plane vibration of a twin calliper disc brake during noise generation.

Phenolic resins have been widely used as a binder for friction materials, but due to the demand for increased performance requirements, it has made the friction suppliers look at modifications to standard phenolic resins. Various modified phenolic resins have been developed and their performance levels and capabilities have been improved. Concern for both the environment and the work place must be considered during the development of any new product. New phenolic resins for friction should therefore be improved to address environmental issues as well as performance issues. New processes have been developed to reduce free phenol and increase yield, at the same time reducing the waste phenol by-product.. Technology for “dust free” resins provides a cleaner working environment at reduced production costs. Furthermore, a combination of these environmental technologies and modifications solves both performance requirements and environmental concerns in the friction industry.

Disc brake squeal can be a major problem during development of new brake systems. Squeal can be loud and persistent or fugitive but nevertheless annoying. Increasing the knowledge of the mechanisms generating squeal is one important contribution to the extensive research and development work being performed in order to solve the problems. The vibration motions of the brake components during squeal, especially the disc, have been studied intensively, and the existence of standing or traveling waves and the direction of such waves have been debated. Several measurement techniques have been employed in order to reveal the nature of the disc motion, including holography, scanning laser vibrometry and rowing accelerometers in the disc. Also acoustic holography has been employed previously - see for example [2] - but this paper documents the ability of acoustic holography to create new knowledge about disc brake squeal through measurement of the disc motion.

In the past, many different remedies have been tried to eliminate the sources of annoying brake noise, e.g., replacing brake hardware, adding shims, resurfacing the rotors, etc. The composition of the brake linings was seldom considered, since asbestos-filled materials possess many characteristics important to low noise operation. With the disappearance of asbestos from brake linings, many other materials were evaluated in order to maintain performance while keeping brake noise to a minimum. Fillers like calcium silicate, glass fiber, mica, etc. offer some similar performance characteristics to asbestos. Friction modifiers, such as metal oxides, metal sulfides, rubber scrap, etc are also used to maintain a more constant coefficient of friction during braking. Among the metal sulfides, molybdenum disulfide (MoS2) is often used since it possesses very good dry lubricating properties.

This paper explores the differences between the tribological behavior of manganese sulfide and a newly developed compound, which is a mixture of manganese sulfide and other inorganic ingredients. Eight formulation were prepared, four containing pure MnS in percentages of 15, 25, 35 & 45%; four containing the new MnS based compound with the same percentages. The base mixture contained phenolic resin, steel wool and inert substances in order not to affect the characteristics of MnS and of the new compound. The tribological properties of the formulations like bedding, pressure sensitivity and fade were evaluated on a Krauss machine. The results showed that manganese sulfide behaved like a typical lubricant with low friction level and deep fades. The data in this paper demonstrates that admixing manganese sulfide with inorganic compounds can produce mixtures that confer good tribological properties on friction formulations.

Friction and noise properties of an asbestos-free low-metal type automotive friction material were evaluated on a brake dynamometer at different sliding speeds and various brake conditions such as burnish, fade, and stability. The wear properties of the brake pad and rotor were also investigated at different initial brake temperatures. The sliding surface was analyzed by using a scanning electron microscopy (SEM). The thermal property of the friction material was tested by differential scanning calorimetry (DSC). These results showed that the wear surface morphologies which were generated by the brake temperature influences the pad wear rate, and the disk thickness variation (DTV) will influence the wear rate of the brake rotor.

Propensity of cold judder was studied by investigating the correlation between the microstructure of gray iron brake disks and friction properties of commercial brake linings. Based on a brake disk for a mid-size passenger car, gray iron disks with 6 different microstructures were manufactured by changing the carbon equivalent (C.E.) and cooling speed in a commercial manufacturing facility. Graphite morphology of the gray iron changed proportionally according to the C.E. and cooling speeds, exhibiting longer graphite flakes with high C.E. at slow cooling speeds. After screening tests of 23 commercial brake linings, 4 different brake linings (two non-steel and two low-steel linings with high μ and low μ) were selected for parasitic drag tests. Results showed that the preferential disk wear was pronounced in the case of using low steel linings and the trend was marked with the disks containing short graphite flakes.

The ever increasing use of electronics in modern vehicles has not stopped at comfort systems such as power seats and power windows. Every conventional system that requires operating force will eventually be replaced by a self-powered version. One such item is the electromechanical parking brake of the new Audi A8, offering a host of new features. Despite the many options for new functions, it is nevertheless important to keep the driver in mind. Being engineers, one tends to overlook that not all customers share our excitement for gadgets and overly complicated technical features.

This paper presents an alternative brake that uses two floating discs, with four rubbing surfaces, to provide a step change improvement in performance over existing products. The paper details the development of this product highlighting the test data, which demonstrates the significant improvements in specific torque, fluid consumption and cooling rates. The design retains conventional materials, existing processes and fits within current package constraints. The sliding discs, which compensate for wear, allow opportunities to simplify the caliper to a fixed design and allow integration with the steering knuckle. Performance, refinement and durability test results indicate the current status of the design as implemented on a small passenger car and an SUV, and show its compatibility with existing vehicle brake control systems. Design options to implement this technology within current and future vehicle systems are also described.

The object of this work was to design an innovative and an improved emergency parking brake system for the automobile. The engineering approach and technical design have been developed based on standard commercially available brake components. This system operates on the basis of pneumatic chambers connected to individual wheel brakes. Under normal driving conditions air pump maintains a certain level of pressure in a special receiver. A system comprised of two automatically operating valves provides high-pressure air delivery to the pneumatic chambers, which switch the parking brake system on or off. In the case of air pump failure there is enough pressure in the receiver for few cycles of on and off braking. In the case of main braking system failure high-pressure emergency brake system could be used for regular braking. The general system design and specific details of each component is described in details.