Search Results

To serve as tools for assessing injury risk, the biofidelity of whole-body pedestrian impact dummies should be validated against reference data from full-scale pedestrian impact tests. To facilitate such evaluations, a simplified generic vehicle-buck has been recently developed that is designed to have characteristics representative of a generic small sedan. Three 40 km/h pedestrian-impact tests have been performed, wherein Post Mortem Human Surrogates (PMHS) were struck laterally in a mid-gait stance by the buck. Corridors for select trajectory measures derived from these tests have been published previously. The goal of this study is to act as a companion dataset to that study, describing the head velocities, body region accelerations (head, spine, pelvis, lower extremities), angular velocities, and buck interaction forces, and injuries observed during those tests.

The objective of the current study was to provide a comprehensive characterization of human biomechanical response to whole-body, lateral impact. Three approximately 50th-percentile adult male PMHS were subjected to right-side pure lateral impacts at 4.3 ± 0.1 m/s using a rigid wall mounted to a rail-mounted sled. Each subject was positioned on a rigid seat and held stationary by a system of tethers until immediately prior to being impacted by the moving wall with 100 mm pelvic offset. Displacement data were obtained using an optoelectronic stereophotogrammetric system that was used to track the 3D motions of the impacting wall sled; seat sled, and reflective targets secured to the head, spine, extremities, ribcage, and shoulder complex of each subject. Kinematic data were also recorded using 3-axis accelerometer cubes secured to the head, pelvis, and spine at the levels of T1, T6, T11, and L3. Chest deformation in the transverse plane was recorded using a single chestband.

The Cummins M-11 high soot diesel engine test is a key tool in evaluating lubricants for the new PC-7 (CH-4) performance category. M-11 rocker arms and crossheads from tests with a wide range of lubricant performance were studied by surface analytical techniques. Abrasive wear by primary soot particles is supported by the predominant appearance of parallel grooves on the worn parts with their widths matching closely the primary soot particle sizes. Soot abrasive action appears to be responsible for removing the protective antiwear film and, thus, abrades against metal parts as well. Subsequent to the removal of the antiwear film, carbide particles, graphite nodules, and other wear debris are abraded, either by soot particles or sliding metal-metal contact, from the crosshead and rocker arm metal surfaces. These particles further accelerate abrasive wear. In addition to abrasive wear, fatigue wear was evident on the engine parts.

One Dimensional models for front end air flows through the cooling system package are very useful for evaluating the effects of component and front end geometry changes. To solve such models for the air flow requires a robust iterative process that involves a number of non-linear sub-models. The cooling fan (s) constitute a major part of the difficulty, especially when they employ a viscous or “thermal” fan drive. This drive varies the torque coupling between the input and output shafts based on the radiator outlet air temperature. The coupling is achieved by viscous shear between two grooved disks and is regulated by a bimetal strip valve that varies the amount of fluid between the disks. This paper presents a mathematical model by which the input/output speed ratio may be determined as a function of the air temperature and input speed. Coefficients in the model are estimated from standard supplier performance information.

One potential fire ignition source in a motor vehicle is the hot surfaces on the engine exhaust system. These hot surfaces can come into contact with combustible and flammable liquids (such as engine oil, transmission fluid, brake fluid, gasoline, or Diesel fuel) due to a fluid leak, or during a vehicle collision. If the surface temperature is higher than the hot surface ignition temperature of the combustible or flammable liquid in a given geometry, a fire can potentially ignite and propagate. In addition to automotive fluids, another potential fuel in post-collision vehicle fires is grass, leaves, or other vegetation. Studies of hot surface ignition of dried vegetation have found that ignition depends on the type of vegetation, surface temperature, duration of contact, and ambient conditions such as temperature and wind speed. Ignition can occur at surface temperatures as low as 300 °C, if the vegetation is in contact with the surface for 10 minutes or longer.

Drop testing of the Hybrid III dummy head was conducted to determine variations in Head Injury Criteria values with the point of head impact, and how the variations relate to actual head injuries. Head drop tests indicated that impacts to the temple and lower forehead posed the greatest injury risks. Moreover, the application of chamois or chalk over the head, a common practice among safety researchers to detect racial lacerations and head contacts, was found to significantly lower Head Injury Criteria values for all impact locations.

This paper describes a three part analysis to characterize the interaction between the female upper extremity and a helicopter cockpit side airbag system and to develop dynamic hyperextension injury criteria for the female elbow joint. Part I involved a series of 10 experiments with an original Army Black Hawk helicopter side airbag. A 5th percentile female Hybrid III instrumented upper extremity was used to demonstrate side airbag upper extremity loading. Two out of the 10 tests resulted in high elbow bending moments of 128 Nm and 144 Nm. Part II included dynamic hyperextension tests on 24 female cadaver elbow joints. The energy source was a drop tower utilizing a three-point bending configuration to apply elbow bending moments matching the previously conducted side airbag tests. Post-test necropsy showed that 16 of the 24 elbow joint tests resulted in injuries.

The Icing Branch at NASA Glenn Research Center has funded an exploratory effort to identify requirements for developing a flight dispatcher-centered web-based icing training program that would be available for all airspace users. Through research and discussions with personnel at airlines, target areas were identified as influences on the requirements for the training system: 1 Flight dispatchers' icing related judgments and decision-making; 2 Certification, new hire and recurrent flight dispatcher training with respect to icing; 3 Icing related weather sources and the problems that flight dispatchers may have in their interpretation; 4 Pedagogical strategies (such as flight dispatcher-centered scenario-based approaches) for delivering flight dispatcher training content; and 5 Concerns/constraints with respect to web-based training for flight dispatchers.

The poisoning of three way catalysts (TWC) by the phosphorus contained in oil formulations containing zinc dialkyldithiophosphate (ZDDP) is examined. Catalysts were exposed to various types of ZDDP and detergents under conditions that were known to reduce performance through phosphorus poisoning without the blocking of sites by formation of glazing. The presence of phosphorus was detected with energy dispersive x-ray spectroscopy (EDX). In addition to analyzing the surface concentration of the phosphorus on the washcoat, the catalyst was cross cut so phosphorus that diffused into the washcoat could be mapped. The total phosphorus in the catalyst could then be calculated. The amount of total phosphorus detected correlated well with the reduced activity of the catalyst as measured by the temperature of 50% conversion.

During a rollover accident the position of an occupant within a vehicle at the time of vehicle-to-ground contact affects the occupant's injury potential and injury mechanisms. During rollovers, the accelerations developed during the airborne phases cause an occupant to move away from the vehicle's center of mass towards the perimeter of the vehicle. The occupant is already in contact with vehicle structures during upper vehicle structure-to-ground impacts. The location and extent of the occupant-to-vehicle contacts and the times and locations at which the contacts occur depend upon a variety of factors including occupant size, initial position in the vehicle, restraint status, vehicle geometry, and rollover accident parameters. Onboard and offboard video of existing dolly rollover studies, specifically the “Malibu” studies, were examined to quantify the motion of the occupants' heads and determine the timing and locations of head contacts to the vehicle perimeter.

Sixty-three simulated frontal impacts using cadaveric specimens were performed to examine and quantify the performance of various contemporary automotive restraint systems. Test specimens were instrumented with accelerometers and chest bands to characterize their mechanical responses during the impact. The resulting thoracic injury severity was determined using detailed autopsy and was classified using the Abbreviated Injury Scale. The ability of various mechanical parameters and combinations of parameters to assess the observed injury severities was examined and resulted in the observation that belt restraint systems generally had higher injury rates than air bag restraint systems for the same level of mechanical responses. To provide better injury evaluations from observed mechanical parameters without prior knowledge of what restraint system was being used, a dichotomous process was developed.

Certain ankylosing spondyloarthropathies such as ankylosing spondylitis (AS) or diffuse idiopathic skeletal hyperostosis (DISH) can substantially alter clinicopathologic spine biomechanics as well as injury mechanisms in rear-end motor vehicle collisions. AS is an inflammatory disease which can lead to structural impairments of the spine secondary to flowing ossification along the spinal column, including ossification across the spinal discs, facet joints, and ligaments, and it has also been associated with diffuse osteoporosis of the spine. DISH is characterized by excess bone formation along the spinal column, encompassing the annulus and forming the thickest and strongest bridging osteophytes over adjacent vertebral bodies at the level of the disc space. In both conditions the spine is mechanically stiffened and generally more kyphotic than a healthy spine.

Injury to the thorax is the predominant cause of fatalities in crash-involved automobile occupants over the age of 65, and many elderly-occupant automobile fatalities occur in crashes below compliance or consumer information test speeds. As the average age of the automotive population increases, thoracic injury prevention in lower severity crashes will play an increasingly important role in automobile safety. This study presents the results of a series of sled tests to investigate the thoracic deformation, kinematic, and injury responses of belted post-mortem human surrogates (PMHS, average age 44 years) and frontal anthropomorphic test devices (ATDs) in low-speed frontal crashes. Nine 29 km/h (three PMHS, three Hybrid III 50th% male ATD, three THOR-NT ATD) and three 38 km/h (one PMHS, two Hybrid III) frontal sled tests were performed to simulate an occupant seated in the right front passenger seat of a mid-sized sedan restrained with a standard (not force-limited) 3-point seatbelt.

Power steering systems provide significant design challenges. They are detrimental to fuel economy since most require the continuous operation of a hydraulic pump. This generates heat that must be dissipated by fluid lines and heat exchangers. This paper presents a simple one-dimensional transient model for power steering components. The model accounts for the pump power, heat dissipation from fluid lines, the power steering cooler, and the influence of radiation heat from exhaust system components. The paper also shows how to use a transient thermal model of the entire system to simulate the temperatures during cyclic operation of the system. The implications to design, drive cycle simulation, and selection of components are highlighted.

The likelihood of a front seat occupant sustaining a femoral shaft fracture in a frontal crash has traditionally been assessed by an injury criterion relying solely on the axial force in the femur. However, recently published analyses of real-world data indicate that femoral shaft fracture occurs at axial loads levels below those found experimentally. One hypothesis attempting to explain this discrepancy suggests that femoral shaft fracture tends to occur as a result of combined axial compression and applied bending. The current study aims to evaluate this hypothesis by investigating how these two loading components interact. Femoral shafts harvested from human cadavers were loaded to failure in axial compression, sagittal plane bending, and combined axial compression and sagittal plane bending.

Field accident data and vehicle crash and sled testing indicate that occupant kinematics, loading, and associated injury risk generally increase with crash severity. Further, these data demonstrate that the use of restraints, such as three-point belts, provides mitigation of kinematics and reduction in loading and injury potential. This study evaluated the role of seat belts in controlling occupant kinematics and reducing occupant loading in moderate severity frontal collisions. Frontal tests with belted and unbelted anthropomorphic test devices (ATDs) in the driver and right front passenger seats were performed at velocity changes (delta-Vs) of approximately 19 kph (12 mph) and 32 kph (20 mph) without airbag deployment. At the lower-moderate severity (19 kph), motion of the belted ATDs was primarily arrested by seat belt engagement, while motion of the unbelted ATDs was primarily arrested by interaction with forward vehicle structures.

Successful product development (PD) includes understanding and delighting customers, anticipating and avoiding failures, and delivering products efficiently. While Design for Six Sigma may be most naturally applied to avoid failures, it has been applied to all three of these areas with varying degrees of success. This paper discusses the advantages and disadvantages of using DFSS to bolster these key elements of PD. Example projects along with successes and shortcomings related to overall PD effectiveness are presented. Whatever form DFSS takes, organizations should make explicit the decision of how to deploy DFSS as part of an overarching quality plan.

Recently there has been a greater awareness of the increased risk of certain injuries associated with air bag deployment, especially the risks to small occupants, often women. These injuries include serious eye and upper extremity injuries and even fatalities. This study investigates the interaction of a deploying air bag with cadaveric upper extremities in a typical driving posture; testing concentrates on female occupants. The goals of this investigation are to determine the risk of upper extremity injury caused by primary contact with a deploying air bag and to elucidate the mechanisms of these upper extremity injuries. Five air bags were used that are representative of a wide range of air bag ‘aggressivities’ in the current automobile fleet. This air bag ‘aggressivity’ was quantified using the response of a dummy forearm under air bag deployment.

This work studies the effect of padding on the force levels in impulsively loaded dummy lower extremities. Tests include the effect of padding incorporated into the soles of shoes and an examination of the potential of shoe padding for mitigating impact loading on the lower extremities. Three different shoes and three paddings were studied using a pendulum impactor; two different padding levels were studied in an impact sled test with simulated translational structural intrusion. The tests indicate a greater than 20% variation in peak axial force imparted to the lower tibia between shoes, and a greater than 50% variation in peak axial force across the paddings tested. From sled tests with simulated structural intruaion, we see a decrease of approximately 15% in peak axial load and a decrease of over 20% in peak anterior/posterior moment.

The 3-D flow field inside an automotive torque converter was measured using laser velocimetry. For the tests, a torque converter completely machined from Plexiglas was operated at the 0.065 and 0.800 turbine/pump speed ratio, and detailed velocities were measured in 13 planes throughout the torque converter. Digital shaft encoder information was used to correlate measured velocities with the pump/turbine angular positions to generate blade-to-blade profiles, 3-D vector plots, and contour through flow plots. Results showed large flow separation regions, jet/wake flows, circulatory secondary flows, and significant flow unsteadiness in all three torque converter elements (pump, turbine, and stator). From the measured velocities, torque converter performance parameters such as mass flows, input/output torque, element incidence angles, slip factors, and vorticities were determined.