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We have recently obtained experimental data and used them to develop computational models to quantify occupant impact responses and injury risks for military vehicles during frontal crashes. The number of experimental tests and model runs are however, relatively small due to their high cost. While this is true across the auto industry, it is particularly critical for the Army and other government agencies operating under tight budget constraints. In this study we investigate through statistical simulations how the injury risk varies if a large number of experimental tests were conducted. We show that the injury risk distribution is skewed to the right implying that, although most physical tests result in a small injury risk, there are occasional physical tests for which the injury risk is extremely large. We compute the probabilities of such events and use them to identify optimum design conditions to minimize such probabilities.

Seat belt anchorage locations have a strong effect on occupant protection. Federal Motor Vehicle Safety Standard (FMVSS) 210 specifies requirements for the layout of the anchorages relative to the seating reference point and seat back angle established by the SAE J826 H-point manikin. Sled testing and computational simulation has established that belt anchorage locations have a strong effect on occupant kinematics, particularly for child occupants using the belt as their primary restraint. As part of a larger study of vehicle geometry, the locations of the anchorage points in the second-row, outboard seating positions of 83 passenger cars and light trucks with a median model year of 2005 were measured. The lower anchorage locations spanned the entire range of lap belt angles permissible under FMVSS 210 and the upper anchorages (D-ring locations) were distributed widely as well.

The factors that influence airbag-induced upper-extremity injuries sustained by drivers were investigated in this study. Seven unembalmed human cadavers were used in nineteen direct-forearm-interaction static deployments. A single horizontal-tear-seam airbag module and two different inflators were used. Spacing between the instrumented forearm and the airbag module was varied from 10 cm to direct contact in some tests. Forearm-bone instrumentation included triaxial accelerometry, crack detection gages, and film targets. Internal airbag pressure was also measured. The observed injuries were largely transverse, oblique, and wedge fractures of the ulna or radius, or both, similar to those reported in field investigations. Tears of the elbow joint capsule were also found, both with and without fracture of the forearm.

Four unembalmed human cadavers were used in eight direct-forearm-airbag-interaction static deployments to assess the relative aggressivity of two different airbag modules. Instrumentation of the forearm bones included triaxial accelerometry, crack detection gages, and film targets. The forearm-fracture predictors, peak and average distal forearm speed (PDFS and ADFS), were evaluated and compared to the incidence of transverse, oblique, and wedge fractures of the radius and ulna. Internal-airbag pressure and axial column loads were also measured. The results of this study support the use of PDFS or ADFS for the prediction of airbag-induced upper-extremity fractures. The results also suggest that there is no direct relationship between internal-airbag pressure and forearm fracture. The less-aggressive system (LAS) examined in this study produced half the number of forearm fracture as the more-aggressive system (MAS), yet exhibited a more aggressive internal-pressure performance.

Three different models of forward-facing CRS were evaluated dynamically using a two-point belt fixation (FMVSS 213 Standard). Ann additional test was conducted with one same model of CRS but using the three-point belt fixation. Results showed that CRS performance differ strongly according to belt fixation being the two-point belt securement dangerously inefficient for children transportation safety.

This paper describes the design and development of a family of surrogate child restraints that are intended for use in developing and testing occupant sensing and classification systems. Detailed measurements were made of the geometry and mass distribution characteristics of 34 commercial child restraints, including infant restraints, convertibles, combination restraints, and boosters. The restraints were installed in three test seats with appropriately sized crash dummies to obtain data on seat-surface pressure patterns and the position and orientation of the restraint with belt loading. The data were used to construct two surrogates with removable components. The convertible surrogate can be used to represent a rear-facing infant restraint with or without a base, a rear-facing convertible, or a forward-facing convertible. The booster surrogate can represent a high-back belt-positioning booster, a backless booster, or a forward-facing-only restraint with a five-point harness.

As passenger car use becomes more common in developing countries, the number of child passengers killed and injuries also increases. Rates of child restraint use appear to be much lower in developing countries than in the U.S. or Europe. One barrier to increased restraint use is the relatively high cost of child restraints in low- and middle-income countries, where the cost of child restraints can be similar to the U.S. but incomes and typical vehicle prices are much lower. As part of a broader effort to improve child passenger safety worldwide, a team at the University of Michigan has begun development of a child restraint that is intended to be fabricated using low-cost technology in developing countries with minimal capital investment. Providing a design that has been tested successfully to regulatory standards may reduce barriers to entry and allow the restraints to be marketed at low prices.

Federal Motor Vehicle Safety Standard (FMVSS) 213 specifies a bench seat that is used in dynamic testing of child restraint systems. To assess the representativeness of the FMVSS 213 bench, data from 54 passenger cars, minivans, and SUVs were analyzed to quantify the side-view profile of the seat centerlines in second-row, outboard seats. SAE J826 H-point measurements were performed on all seats and on the FMVSS 213 bench. A landmark-based resampling method was used to obtain a meaningful average seat contour after aligning on H-point. Principal component analysis and regression were conducted to quantify the effects of seat cushion angle, cushion length, and back angle on the seat profile. When aligned on H-point, the cushion length and surface angles of the FMVSS 213 bench were similar to the mean contour, except that no seats were as flat as the bench profile.

Reliable, accurate data on vehicle occupant characteristics could be used to personalize the occupant experience, potentially improving both satisfaction and safety. Recent improvements in 3D camera technology and increased use of cameras in vehicles offer the capability to effectively capture data on vehicle occupant characteristics, including size, shape, posture, and position. In previous work, the body dimensions of standing individuals were reliably estimated by fitting a statistical body shape model (SBSM) to data from a consumer-grade depth camera (Microsoft Kinect). In the current study, the methodology was extended to consider seated vehicle occupants. The SBSM used in this work was developed using laser scan data gathered from 147 children with stature ranging from 100 to 160 cm and BMI from 12 to 27 kg/m2 in various sitting postures.

Law enforcement officers (LEO) make extensive use of vehicles to perform their jobs, often spending large portions of a shift behind the wheel. Few LEO vehicles are purpose-built; the vast majority are modified civilian vehicles. Data from the field indicate that LEO suffer from relatively high levels musculoskeletal injury that may be due in part to poor accommodation provided by their vehicles. LEO are also exposed to elevated crash injury risk, which may be exacerbated by a compromise in the performance of the occupant restraint systems due to body-borne equipment. A pilot study was conducted to demonstrate the application of three-dimensional anthropometric scanning and measurement technology to address critical concerns related to vehicle design. Detailed posture and belt fit data were gathered from five law enforcement officers as they sat in the patrol vehicles that they regularly used and in a mockup of a mid-sized vehicle.

The objective of this study was to optimize the occupant restraint systems for a light tactical vehicle in frontal crashes. A combination of sled testing and computational modeling were performed to find the optimal seatbelt and airbag designs for protecting occupants represented by three size of ATDs and two military gear configurations. This study started with 20 sled frontal crash tests to setup the baseline performance of existing seatbelts, which have been presented previously; followed by parametric computational simulations to find the best combinations of seatbelt and airbag designs for different sizes of ATDs and military gear configurations involving both driver and passengers. Then 12 sled tests were conducted with the simulation-recommended restraint designs. The test results were further used to validate the models. Another series of computational simulations and 4 sled tests were performed to fine-tune the optimal restraint design solutions.

Static deployments of driver-side airbags into the legs of human subjects were used to investigate the effects of inflator capacity, internal airbag tethering, airbag fabric, and the distance from the module on airbag-induced skin abrasion. Abrasion mechanisms were described by measurements of airbag fabric velocity and target surface pressure. Airbag fabric kinematics resulting in three distinct abrasion patterns were identified. For all cases, abrasions were found to be caused primarily by high-velocity fabric impactrather than scraping associated with lateral fabric motion. Use of higher-capacity inflators increased abrasion severity, and untethered airbags produced more severe abrasions than tethered airbags at distances greater than the length of the tether. Abrasion severity decreased as the distance increased from 225 to 450 mm. Use of a finer-weave airbag fabric in place of a coarser-weave fabric did not decrease the severity of abrasion.

Although driver-side airbag systems provide protection against serious head and chest injuries in frontal impacts, injuries produced by the airbag itself have also been reported. Most of these injuries are relatively minor, and consist primarily of skin abrasions and burns. Previous investigations have addressed the mechanisms of airbag-induced skin abrasion. In the current research, laboratory studies related to the potential for thermal burns due to high-temperature airbag exhaust gas were conducted. A laboratory apparatus was constructed to produce a 10-mm-diameter jet of hot air that was directed onto the leg skin of human volunteers in time-controlled pulses. Skin burns were produced in 70 of 183 exposures conducted using air temperatures ranging from 350 to 550°C, air velocities from 50 to 90 m/s, and exposure durations from 50 to 300 ms.

The UMTRI Airbag Skin Burn Model has been improved through laboratory testing and the implementation of a more flexible heat transfer model. A new impinging jet module based on laboratory measurements of heat flux due to high-velocity gas jets has been added, along with an implicit finite-difference skin conduction module. The new model can be used with airbag gas dynamics simulation outputs, or with heat flux data measured in the laboratory, to predict the potential for thermal skin burn due to exposure to airbag exhaust gas.

Two new techniques for investigating the thermal skin-burn potential of airbags are presented. A reduced-volume airbag test procedure has been developed to obtain airbag pressures that are representative of a dynamic ridedown event during a static deployment. Temperature and heat flux measurements made with this procedure can be used to predict airbag thermal burn potential. Measurements from the reduced-volume procedure are complemented by data obtained using two gas-jet simulators, called heatguns. Gas is vented in controlled bursts from a large, heated, pressurized tank of gas onto a target surface. Heat flux measurements on the target surface have been used to develop quantitative models of the relationships between gas jet characteristics and burn potential.

Advanced airbag systems use information from a variety of sensors to tune the airbag performance for crash severity and occupant characteristics. A new family of Occupant Classification ATDs (OCATD) have been developed for use in the design and testing of advanced airbag systems. This paper describes the development of anthropometric standards for an OCATD that represents a typical six-year-old child. Detailed analyses of existing child anthropometry databases were conducted to develop reference dimensions. A child who closely matched the reference dimensions was measured in a variety of conditions. A custom molded measurement seat was constructed using foam-in-place seating material. The surface of the child's body was scanned as he sat in the custom seat, and the three-dimensional locations of body landmarks defining the skeleton position were recorded.

This paper presents a laboratory study of body dimensions, seated posture, and seatbelt fit for children weighing from 40 to 100 lb (18 to 45 kg). Sixty-two boys and girls were measured in three vehicle seats with and without each of three belt-positioning boosters. In addition to standard anthropometric measurements, three-dimensional body landmark locations were recorded with a coordinate digitizer in sitter-selected and standardized postures. This new database quantifies the vehicle-seated postures of children and provides quantitative evidence of the effects of belt-positioning boosters on belt fit. The data will provide guidance for child restraint design, crash dummy development, and crash dummy positioning procedures.

A detailed understanding of the size, shape, and postures of children is required to design effective restraint systems for protecting children in motor vehicle crashes. Compiled and edited by experts in the fields of anthropometry, ergonomics, and child restraint, this book includes 14 important papers which provide a comprehensive overview of the methods for collecting, analyzing, and applying child anthropometry data for crash safety purposes. A detailed understanding of the size, shape, and postures of children is required to design effective restraint systems for protecting children in motor vehicle crashes. Compiled and edited by experts in the fields of anthropometry, ergonomics, and child restraint, this book includes 14 important papers which provide a comprehensive overview of the methods for collecting, analyzing, and applying child anthropometry data for crash safety purposes.

To determine the frequency of facial injuries from steering-wheel airbag deployments, 540 consecutive steering-wheel airbag deployments, investigated by the University of Michigan Transportation Research Institute (UMTRI) personnel, were reviewed. About 1 in 3 drivers sustain an injury to the face. Injuries to the area surrounding the eye (periorbital) or to the eyeball (ocular) rarely occur. The frequencies of facial or ocular injuries are the same for belted and unbelted drivers. Drivers of short stature had a higher frequency of facial injury. Females sustained ocular injuries more frequently than males. Untethered airbags were not overly involved in drivers with an ocular injury. No specific make or model car were overly represented in the ocular injury cases.

In recent investigations of airbag deployments, drivers h v c reported abrasions to the face, neck, and forearms due to deploying airbags, A study of the airbag design and deployments parameters affecting the incidence and severity of abrasions caused by driver-side airbags has led to the development of a laboratory test procedure to evaluate the potential of an airbag design m cause skin injury This report describes the procedure, which is based an static deployments of airbags into a cylindrical lest fixture. The target area is covered with a material that responds to abrasion-producing events in a manner related to human skin tolerance. Test results show excellent correlation with abrasion injuries produced by airbag deployments into the skin of human volunteers.