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Technical Paper

A More Effective Post-Crash Safety Feature to Improve the Medical Outcome of Injured Occupants

2006-04-03
2006-01-0675
Automatic Crash Notification (ACN) technology provides an opportunity to rapidly transmit crash characteristics to emergency care providers in order to improve timeliness and quality of care provided to occupants in the post crash phase. This study evaluated the relative value of crash attributes in providing useful information to assist in the identification of crashes where occupants may be seriously injured. This identification includes an indication of whether a crash is likely to require a level of emergency response with higher priority than is needed for most crashes reported by ACN Systems. The ability to predict serious injury using groupings of variables has been determined. In this way, the consequence of not transmitting each variable can be estimated. In addition, the incremental benefit of voice communication is shown.
Technical Paper

Effect of Occupant Position and Air Bag Inflation Parameters on Driver Injury Measures

1998-02-23
980637
This paper investigates the effects of driver airbag inflation characteristics, airbag relative position, airbag to dummy relative velocity, and steering column characteristics using a finite element model of a vehicle, air bag, and Hybrid III 50% male dummy. Simulation is conducted in a static test environment using a validated finite element model. Several static simulation tests are performed where the air bag module's position is mounted in a rigid steering wheel and the vertical and horizontal distances are varied relative to the dummy. Three vertical alignments are used: one position corresponds to the head centered on module, another position corresponds to the neck centered on module, and the third position centers the chest on the module. Horizontal alignments vary from 0 mm to 50 mm to 100 mm. All of these tests are simulated using a typical pre-1998 type inflation curve (mass flow rate of gas entering the bag).
Technical Paper

Evaluating Frontal Crash Test Force-Deformation Data for Vehicle to Vehicle Frontal Crash Compatibility

2008-04-14
2008-01-0813
Vehicle stiffness is one of the three major factors in vehicle to vehicle compatibility in a frontal crash; the other two factors are vehicle mass and frontal geometry. Vehicle to vehicle compatibility in turn is an increasingly important topic due to the rapid change in the size and characteristics of the automotive fleet, particularly the increase of the percentage of trucks and SUVs. Due to the non-linear nature of the mechanics of vehicle structure, frontal stiffness is not a properly defined metric. This research is aimed at developing a well defined method to quantify frontal stiffness for vehicle-to-vehicle crash compatibility. The method to be developed should predict crash outcome and controlling the defined metric should improve the crash outcome. The criterion that is used to judge the aggressivity of a vehicle in this method is the amount of deformation caused to the vulnerable vehicles when crashed with the subject vehicle.
Technical Paper

Evaluation of Different Roof Strength Methods in Quasi-Static and Dynamic Rollover Tests Using Finite Element Analysis of a 2003 Ford Explorer Model

2014-04-01
2014-01-0532
Different roof strength methods are applied on the 2003 Ford Explorer finite element (FE) model to achieve the current Federal Motor Vehicle Safety Standard (FMVSS) 216 requirements. Two different modification approaches are utilized. Additionally, the best design of each approach is tested dynamically, in rollover and side impact simulations. In the first approach, several roll cage designs are integrated in all pillars, roof cross-members, and in the side roof rails. A roll cage design with a strength-to-weight ratio (SWR) of 3.58 and 3.40 for driver and passenger sides, respectively, with a weight penalty of 18.54 kg is selected for dynamic test assessments. The second approach investigates different localized reinforcements to achieve a more reasonable weight penalty. A localized reinforcement of the B-pillar alone with a tube meets the new FMVSS 216 requirements with a weight penalty of 4.52 kg and is selected for dynamic analyses.
Technical Paper

Far-Side Impact Vehicle Simulations with MADYMO

2007-04-16
2007-01-0363
To date, anthropomorphic test devices (ATDs) have not been designed with consideration for human motion in far-side impacts. Previous tests with a cadaver and a BioSID dummy at the Medical College of Wisconsin confirmed that the dummy does not suitably model the human motion. To further evaluate different ATDs in far-side crashes, MAthematical DYnamic MOdeling (MADYMO) was employed. The modeling showed that the motion of a Hybrid III, BioSID, EuroSid1, EuroSID2, or SID2s did not accurately reflect the motion of a human cadaver under the same impact configurations as the cadaver test. The MADYMO human facet model was found to closely reproduce the kinematics of the cadaver test. The effect of varying console designs on occupant kinematics is presented in this paper. The human facet model appears to be a good interim tool for the evaluation of countermeasures in far-side crashes.
Technical Paper

Foot and Ankle Injuries to Drivers in Between-Rail Crashes

2013-04-08
2013-01-1243
The research question investigated in this study is what are the key attributes of foot and ankle injury in the between-rail frontal crash? For the foot and ankle, what was the type of interior surface contacted and the type of resulting trauma? The method was to study with in-depth case reviews of NASS-CDS cases where a driver suffered an AIS=2 foot or ankle injury in between-rail crashes. Cases were limited to belted occupants in vehicles equipped with air bags. The reviews concentrated on coded and non-coded data, identifying especially those factors contributing to the injuries of the driver's foot/ankle. This study examines real-world crash data between the years 1997-2009 with a focus on frontal crashes involving 1997 and later model year vehicles. The raw data count for between-rail crashes was 732, corresponding to 227,305 weighted, tow-away crashes.
Technical Paper

Frontal Crash Testing and Vehicle Safety Designs: A Historical Perspective Based on Crash Test Studies

2010-04-12
2010-01-1024
This study tracks vehicle design changes and frontal crash test performance in NHTSA's NCAP and IIHS consumer information tests since the mid-90s for the Honda Accord and Toyota Camry. The objective was to provide insights into how passenger cars have changed in response to frontal consumer information tests. The history of major design changes for each model was researched and documented. The occupant injury measures from both NHTSA and IIHS were computed and the ratings compiled for several generations of both vehicles. Changes in vehicle crash pulse and occupant injury measures from both NCAP and IIHS tests, and from Canadian low speed rigid barrier tests, when available, were used to assess driver frontal protection for various vehicle generations. Loading of the rigid barrier in NCAP tests was used to evaluate front end stiffness changes over the years.
Technical Paper

Heart Injuries Among Restrained Occupants in Frontal Crashes

1997-02-24
970392
The William Lehman Injury Research Center has conducted multi-disciplinary investigations of one hundred seventy-eight crashes involving adult occupants protected by safety belts and air bags. In all cases, serious injuries were suspected. Nine cases involved serious heart injuries. These cases are not representative of crashes in general. However, when used in conjunction with National Accident Sampling System; Crashworthiness Data System (NASS/CDS) they provide insight into the most severe injuries suffered by restrained occupants in frontal crashes. Heart injuries are rare, but when they occur they are usually life threatening. NASS/CDS shows that heart injuries comprise about 0.2% of the injuries in frontal tow-away crashes. In the NHTSA file of Special Crash Investigations (SCI) of air bag cases, heart injuries are reported in 1% of the occupants over 15 years of age. Twenty-five percent of the fatally injured occupants had heart injuries, and 83% of those with heart injury died.
Technical Paper

INJURIES TO RESTRAINED OCCUPANTS IN FAR-SIDE CRASHES

2001-06-04
2001-06-0149
Occupants exposed to far-side crashes are those seated on the side of the vehicle opposite the struck side. This study uses the NASS/CDS 1988–98 to determine distributions of serious injuries among restrained occupants exposed to far-side crashes and the sources of the injuries. Vehicle-to-vehicle crash tests were conducted to study dummy kinematics. The NASS/CDS indicated that the head accounted for 45% of the MAIS 4+ injuries in far-side collisions and the chest/abdomen accounted for 39%. The opposite-side interior was the most frequent contact associated with driver AIS 3+ injuries (26.9%). The safety belt was second, accounting for 20.8%. Vehicle-to-vehicle side impact tests with a 60 degree crash vector indicated that different safety belt designs resulted in different amounts of head excursion for the far side Hybrid III dummy. For all three point belt systems tested, the shoulder belt was ineffective in preventing large amounts of head excursion.
Technical Paper

New Method of Vehicle Inspection for Incompatible Crashes

2007-04-16
2007-01-1184
This paper creates a worksheet to thoroughly document vehicle damage during an incompatible vehicle-to-vehicle frontal crash. This data form serves as a supplement to the current and already established NASS inspection forms. It will assist biomechanics research by determining the extent by which incompatibility caused or changed occupants' injuries through structural analysis of the vehicles. This study identifies deficiencies in the current NASS inspection system for compatibility, and develops new measurable parameters to document the crash and associate injury to it.
Technical Paper

Protection of Rear Seat Occupants in Frontal Crashes, Controlling for Occupant and Crash Characteristics

2009-11-02
2009-22-0003
In this study, the level of protection offered to rear seat occupants in frontal crashes is investigated. The Fatality Analysis Reporting System (FARS) and National Automotive Sampling System Crashworthiness Data System (NASS CDS) databases were used for the analyses. The investigation focused on: 1- estimating the fatality protection effectiveness of the rear seat position relative to the right front seat position, using the double paired comparison method, 2- evaluating the effect of control group selection method on effectiveness predictions, and 3- identifying trends in rear seat occupant protection over model years of vehicles. By applying a uniform control group to the double paired comparison analysis of FARS data, this study suggests that all ages of occupants are safer in the rear seat than in the right front seat. Effectiveness estimates ranged from 5.9% to 82% for different age groups of occupants.
Technical Paper

Side Impact Injury Risk for Belted Far Side Passenger Vehicle Occupants

2005-04-11
2005-01-0287
In a side impact, the occupants on both the struck, or near side, of the vehicle and the occupants on the opposite, or far side, of the vehicle are at risk of injury. Since model year 1997, all passenger cars in the U.S. have been required to comply with FMVSS No. 214, a safety standard that mandates a minimum level of side crash protection for near side occupants. No such federal safety standard exists for far side occupants. The mechanism of far side injury is believed to be quite different than the injury mechanism for near side injury. Far side impact protection may require the development of different countermeasures than those which are effective for near side impact protection. This paper evaluates the risk of side crash injury for far side occupants as a basis for developing far side impact injury countermeasures. Based on the analysis of NASS/CDS 1993–2002, this study examines the injury outcome of over 4500 car, light truck, and van occupants subjected to far side impact.
Technical Paper

Side Impact Risk for 7-13 Year Old Children

2008-04-14
2008-01-0192
The purpose of this paper is to assess the vehicle environment that a child occupant, between the ages of seven and thirteen years old, is exposed to in a real world crash. The focus of analysis is on those child occupants that are seated at the struck side in a lateral collision. This study was based on data extracted from the National Automotive Sampling System / Crashworthiness Data System (NASS/CDS) between years 1991-2006. Analysis was based upon the evaluation of the projected consequence of injury to the child occupants. The societal costs generated as a result of occupant injuries were quantified. The societal cost, or Harm, acts as a measure of consequence of occupant exposure to the vehicle environment, when involved in a collision. The Harm was determined as a function of ΔV, principal direction of force, vehicle extent of damage, the pattern of damage to the vehicle, and the magnitude of intrusion based on the occupant seating position.
Technical Paper

Simulation of Road Crash Facial Lacerations By Broken Windshields

1987-02-23
870320
The facial laceration test has been proposed as an addition to the dummy injury criteria of Federal Motor Vehicle Safety Standard 208. To better understand laceration conditions as they actually occur, three road crashes of increasing severity, all involving facial laceration by the broken (cracked) windshield and one involving partial ejection, have been simulated physically and analytically. The physical simulations used vehicle test bucks, the Hybrid III head with the chamois facial coverings of the facial laceration test, and a piston - constrained Head Impactor. Computer simulations of the three crashes were also carried out using the CALSPAN 3D “CVS” and the 2D “DRISIM” computer programs. The computer simulations provide insight into the effective mass of the head and body on windshield contact, and the forces, velocities, and accelerations involved.
Technical Paper

The Role of Intrusion in Injury Causation in Frontal Crashes

2005-04-11
2005-01-1376
In December 2003, fifteen participating Automobile Manufacturers announced the adoption of voluntary standards for geometric compatibility in frontal crashes. In an October 2003 report, Insurance Institute of Highway Safety (IIHS) estimated that an 8 to 28 percent fatality reduction might be achieved with better geometric and stiffness compatibility (O’Neill, 2003). This benefit was based on comparing the fatality risks of car occupants in car-to-car collisions and in car-to-SUV collisions. Reduced occupant compartment intrusion was cited as the principal advantage gained by compatibility improvements. However, the study did not actually examine the role that intrusion played in causing the fatalities. This study examines the magnitude of serious injuries in frontal crashes that could be addressed by reducing occupant compartment intrusion. Each frontal vehicle-to-vehicle case in William Lehman Injury Research Center (WLIRC) data was examined to determine the cause of each injury.
Technical Paper

Trend of Rear Occupant Protection in Frontal Crashes over Model Years of Vehicles

2009-04-20
2009-01-0377
The National Automotive Sampling System’s Crashworthiness Data System (NASS CDS) was used to study rear occupant injuries in frontal crashes. The risks of injury for the rear passengers of different age groups were calculated and compared to the risks of injury for the front occupants. Furthermore, the risks of injury were investigated for the rear and front adult occupants over model years of vehicles. Distribution of injuries among body regions and vehicle contact points were also investigated for the rear adult occupants. While the rear occupants were more protected than the front occupants in most of the groups studied, an increasing trend was observed in the risk of injury of the rear adult occupants over the model years of the vehicles.
Technical Paper

Using CIREN Data to Assess the Performance of the Second Generation of Air Bags

2004-03-08
2004-01-0842
The U.S. Department of Transportation-sponsored Crash Injury Research and Engineering Network (CIREN) program offers a reasonable look at the efficacy of second-generation air bags. This paper examines the data from the William Lehman Injury Research Center (WLIRC). The WLIRC data is a near census of crashes in the Miami-Dade region with occupants that appear to be severely injured. The percentage of deaths among trauma patients in the WLIRC data as a function of delta-V for first-generation air bags was higher than expected at lower delta-V's. There were nine driver fatalities at delta-V's of less than 20 mph (four involving short stature occupants, four with elderly occupants, and one due to significant intrusion and/or vehicle incompatibility). The data supported NHTSA's conclusion that first-generation air bags were too aggressive for occupants in close proximity to the deploying air bag and too aggressive for older persons.
Journal Article

Validation of Sled Tests for Far-Side Occupant Kinematics Using MADYMO

2010-04-12
2010-01-1160
Far-side occupants are not addressed in current government regulations around the world even though they account for up to 40% of occupant HARM in side impact crashes. Consequently, there are very few crash tests with far-side dummies available to researchers. Sled tests are frequently used to replicate the dynamic conditions of a full-scale crash test in a controlled setting. However, in far-side crashes the complexity of the occupant kinematics is increased by the longer duration of the motion and by the increased rotation of the vehicle. The successful duplication of occupant motion in these crashes confirms that a sled test is an effective, cost-efficient means of testing and developing far-side occupant restraints or injury countermeasures.
Technical Paper

Vehicle Frontal Stiffness in a Front to Front Crash

2005-04-11
2005-01-1375
In the effort to understand and solve the frontal crash compatibility problem, one needs to use values of frontal stiffness. Various definitions of stiffness have been used in other studies based on measurements from NHTSA's 35mph frontal NCAP test. Those definitions varied from assuming a linear stiffness based on static crush to more refined ones that vary with time dependent crush. A major consideration in selecting a method is the amount of vehicle damage that occurs in an incompatible crash. To partially address this issue, a method was introduced based on the energy absorbed in a front to front crash at 25mph approach speed. Four alternative definitions of stiffness were studied.
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