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Technical Paper

Analysis of Road Traffic Accidents on NH 45 (Kanchipuram District)

2009-12-13
2009-28-0056
With the support and cooperation of the Kanchipuram district police and Tamil Nadu police, researchers conducted detailed investigations of accidents occurring on the National Highway 45 over a 60 km stretch. The primary objective was to collect and analyze India-based traffic crash data to begin to create a sound basis for decision making for improving safety on India's roadways. A secondary objective was to establish a standardized methodology using economical tools for collecting and analyzing crash data, specific to Indian roads. For the 45 day study period, an accident intimation network was established between researchers and all police stations/highway patrols in the study area. On occurrence of an accident, police called a 24-hour contact number and researchers responded to the scene. On site, researchers used standardized reporting forms, methodologies, and equipment to perform accident scene examinations, accident vehicle examination, and AIS injury coding.
Technical Paper

Dashboard Stiffness Control for Reducing Knee Injury in Frontal Crashes

2009-01-21
2009-26-0006
In frontal crashes, one of the primary reasons for occupant injuries is hard contact with the vehicle interiors. While restraints like airbags, seat belt pre-tensioners etc. help in preventing direct contact of the upper body region; vehicle interiors play a critical role in controlling the lower body region injuries. Knee injuries can be controlled in various ways as follows: Avoiding contact with the dashboard by use of buckle pre-tensioners etc. Using restraints like knee airbags Optimizing the dashboard profile and stiffness at the contact locations All the above options have their own advantages and limitations. This paper explains the effect of dashboard stiffness tuning for controlling knee injuries in a frontal crash. The development methodology and some validation tools are discussed using a case study.
Technical Paper

Efficient and Cost Effective Energy Absorbers for Automotive Bumper: A Novel Energy Absorber

2009-01-21
2009-26-0009
During recent years, the development of new vehicles has to cope with continuously emerging requirements, implemented by new legislation and consumer test (eg. EuroNCAP) to insure occupant and pedestrian protection as well as new insurance classification test to improve vehicle damageability and repairability. These conflicting requirements have pose significant challenge to car manufacturers and designers to tune the vehicle front styling to meet pedestrian norm at the same time reduce damage to vehicle structure to minimize repair cost. Today Indian automotive OEM's are expanding their arms in global platform and need to design compliant vehicle front structure to meet these regulations requirements. Bumper is the first component that will come in contact during pedestrian or car-to-car impact and has a main role in damping the impact and minimize the injury. This paper explores injection molded thermoplastic energy absorber solution to meet pedestrian safety.
Technical Paper

Development of Sensor Attachment Criteria (Immunity) - Side Impact Sensor Mounted on Door Impact Beam

2011-04-12
2011-01-1445
The sensor mounted on the door impact beam plays a major role in side impact events. The accelerations of side impact sensors are processed by sensing algorithms to make a decision on the air bag deployment. The sensing signal criterion for the deployable condition is a well understood process. However, the non-deployment sensing signal for the immunity to abuse conditions is a function of sensor attachment stiffness to the base structure. The base structure can be a door inner panel or door impact beam. In one of the production program, the acceleration based sensor attached to the impact beam showed immunity issues in the abusive door slams/opening to objects. Hence, the computer Aided Engineering (CAE) analysis was used to develop the sensor attachment criterion.
Journal Article

Data Extraction Methods and their Effects on the Retention of Event Data Contained in the Electronic Control Modules of Detroit Diesel and Mercedes-Benz Engines

2011-04-12
2011-01-0808
The Electronic Control Modules (ECMs) aboard many on-highway commercial motor vehicles contain event data useful to the investigation and reconstruction of motor vehicle collisions [1,2,3,4]. Methods of extracting such event data include: connecting to the ECMs through the vehicle's Off-Board Diagnostics Connector (a 6 or 9 pin connector typically found inside the vehicle near the driver's seat); connecting directly to any ECMs while they are still connected to the engine; and connecting directly to the ECMs after they are removed from the engine (a method typically referred to as a Bench image). This research is an attempt to document the effects of these data-extraction methods on the retention of the event data contained in the ECMs of the on-highway commercial motor vehicle engines manufactured by Detroit Diesel and Mercedes-Benz.
Technical Paper

Failure Evaluation of Clinched Thin Gauged Pedestrian Friendly Hood by Slam Simulation

2011-04-12
2011-01-0789
In order to reduce the number of head injuries sustained by pedestrian accidents, safety engineers are developing pedestrian friendly hood systems through gauge optimization of the hood inner panel. In this study, the clinch method was employed to assemble a pedestrian friendly hood with a 0.5mm thick inner panel. Static and dynamic analyses were carried out to determine the clinch experiencing the highest loads and to understand the fatigue behavior of a clinched hood during a slam event. The macroscopic failure modes of clinched joints by hood slam were studied by means of a scanning electron microscope. A simple equation was derived to correlate the hexahedron spot weld model as a substitute for clinching in order to obtain an equivalent stiffness for a clinched joint within the linear region of an F-D curve. The F-D curve was obtained by lap shear testing.
Technical Paper

Development of an Optimized Structure for Meeting Pedestrian Protection Requirements

2011-04-12
2011-01-0770
In recent years, pedestrian protection from passenger car impacts has become an important issue. In this study, a lower stiffener system has been implemented in order to reduce lower leg injuries. This system was developed using finite element analyses and impact testing. Injury criteria including bending angle, shear displacement, and deflection were studied in the analyses. These variables were optimized using a DOE (Design of Experiments) sensitivity analysis.
Technical Paper

A Comparative Study of Rollover Crashes Involving Passenger Cars With and Without Electronic Stability Control (ESC)

2011-04-12
2011-01-0951
The analysis presented here updates and expands previous research in which rollover critical events were classified based on a detailed review of about 500 police-reported single-vehicle rollover crashes of ESC-equipped vehicles. In order to compare the rollover performance of vehicles with and without ESC for the present study, an additional sample of 150 police reports on non-ESC passenger cars and 196 police reports on light vehicles with ESC in single-vehicle rollovers were obtained, and detailed coding of rollover scenarios was performed. The coding effort was undertaken by an engineering team and focused on critical events leading to rollovers (departure from road, loss of directional control, impact with an object, and departure from road with possible driver's input); driver factors (alcohol/drug involvement, speeding, inattention, distraction, fatigue, and overcorrection); and environmental factors.
Technical Paper

Jack-Knife Prevention for Articulated Vehicles Using Self-Organizing Fuzzy Control

2011-04-12
2011-01-0988
In this research the differential braking design for articulated vehicle jackknife prevention is investigated. To handle the variations in the semi-trailer loading condition, a self-organizing fuzzy control that can update its control law through a set of learning algorithms is employed. Two different types of driving scenarios are investigated, namely the constant speed step steering and a fish hook maneuver. Computer simulations, both using a linearized vehicle model and the TruckSim® vehicle model, indicate that the SOFC performs consistently well in tracking the desired fifth wheel angle under different loading conditions
Technical Paper

Probability of a Crash During Plug-in Charging

2011-04-12
2011-01-1008
Plug-in electric vehicles are becoming increasingly popular as the U.S. and other nations look for ways to reduce the usage of petroleum fuels and reduce the carbon emission footprint. Though plug-in electric vehicles offer many advantages over conventional vehicles, they also present some unique potential hazards due to the presence of high voltage in the vehicle. Specifically, potential high voltage hazards can occur if the electric vehicle is crashed by another vehicle during its plug-in charging session. High voltage hazards include the possibility of electrical shock and thermal events as a result of electrical arcing that can cause injury or death to persons that operate or work around plug-in electric vehicles. Automotive Safety Integrity Level (ISO 26262), often abbreviated as ASIL, is used by the automotive industry for determining the ranking of safety hazards.
Technical Paper

Accurate Simulation of Door Side Intrusion in Automotive Structures with Progressive Fracture

2011-04-12
2011-01-1070
Door side intrusion (FMVSS 214, Static) is a quasi-static test to determine the sufficiency of door strength and integrity of its mounting in the event of side impact. Explicit nonlinear solutions are often adapted for simulating the side intrusion test performance using the finite element method. The side intrusion performance involves intense rupture at panels as well as their connections such as spot welds, bolts and hems. The load path changes significantly with the material fracture in the panels and at their connections. Conventional finite element models assuming no material separation cannot capture such load path changes and cannot recognize the associated loss in structural integrity. Accordingly, the conventional nonlinear finite element analysis tends to over-predict the intrusion strengths by a large margin and fails to predict the potential separation of the door from the body at the latch and hinge connections.
Technical Paper

A Study of Driver Injury Mechanism in High Speed Lateral Impacts of Stock Car Auto Racing Using a Human Body FE Model

2011-04-12
2011-01-1104
This paper analyzed the mechanisms of injury in high speed, right-lateral impacts of stock car auto racing, and interaction of the occupant and the seat system for the purpose of reducing the risk of injury, primarily rib fractures. Many safety improvements have been made to stock car racing recently, including the Head and Neck Support devices (HANS®), the 6-point restraint harnesses, and the implementation of the SAFER Barrier. These improvements have contributed greatly to mitigating injury during the race crash event. However, there is still potential to improve the seat structure and the understanding of the interaction between the driver and the seat in the continuation of making racing safety improvements. This is particularly true in the case of right-lateral impacts where the primary interaction is between the seat supports and the driver and where the chest is the primary region of injury.
Technical Paper

Field Effectiveness Calculation of Integrated Safety Systems

2011-04-12
2011-01-1101
The potential of determining the change of injury severity in the accident event taking passive as well as active measures into account at the vehicle (integral systems) are at present limited to pedestrian protective systems. Therefore, an extension of the existing methods for the application with common integral systems (front protection, side protection, etc.) is suggested. Nowadays the effectiveness of passive safety systems is determined in crash tests with very high accident severities. However, approximately 90% of real-world accidents have a lower accident severity as the required crash tests. Thus, this paper will present a method calculating the effectiveness of such an integral system based on real-world accident data. For these reasons, this paper is presenting a method for a more valid prediction of injury severity. The German In-Depth Database GIDAS allows clustering the accident event in relevant car-to-car scenarios.
Journal Article

A Component Test Methodology for Simulation of Full-Vehicle Side Impact Dummy Abdomen Responses for Door Trim Evaluation

2011-04-12
2011-01-1097
Described in this paper is a component test methodology to evaluate the door trim armrest performance in an Insurance Institute for Highway Safety (IIHS) side impact test and to predict the SID-IIs abdomen injury metrics (rib deflection, deflection rate and V*C). The test methodology consisted of a sub-assembly of two SID-IIs abdomen ribs with spine box, mounted on a linear bearing and allowed to translate in the direction of impact. The spine box with the assembly of two abdominal ribs was rigidly attached to the sliding test fixture, and is stationary at the start of the test. The door trim armrest was mounted on the impactor, which was prescribed the door velocity profile obtained from full-vehicle test. The location and orientation of the armrest relative to the dummy abdomen ribs was maintained the same as in the full-vehicle test.
Journal Article

Comparing Dolly Rollover Testing to Steer-Induced Rollover Events for an Enhanced Understanding of Off-Road Rollover Dynamics

2011-04-12
2011-01-1112
The field of motor vehicle rollover research and testing has been one of multiple and varied approaches, dating back to at least the 1930's. The approach has been as simple as tipping a vehicle over at the top of a steep hill ( Wilson et al., 1972 ), to as complex as releasing a vehicle from an elevated roll spit mounted to the rear of a moving tractor and trailer ( Cooper et al., 2001 and Carter et al., 2002 ). Between these extremes exists numerous other rollover initiation methods, including driving a vehicle into a ramp, sliding a vehicle sideways into soil or a curb-like obstruction, launching or releasing a vehicle from a dolly cart, and remotely steering a moving vehicle into an orientation that will produce a rollover event ( Cooperrider et al., 1990 and Larson et al., 2000 ).
Technical Paper

Rollover Crash Test Results: Steer-Induced Rollovers

2011-04-12
2011-01-1114
A series of rollover tests was conducted in a real-world environment in which a vehicle was driven or towed to highway speed then steered to induce a rollover. This research presents analysis of the rollover phase of five tests. In each test, the steering maneuver was initiated on-pavement, and the rollover was caused by tire-to-ground interaction. Tests included vehicles that tripped both on-pavement and on soil. Four tests ended with the vehicle at rest off-road, and one ended with the vehicle remaining on the pavement. A programmable remote control radio was used to steer the vehicles through a double-step steer maneuver to result in a rollover. The test vehicles were instrumented and data was collected during each test, including steering, suspension motion, rotational rates, and accelerations. A Global Positioning System (GPS) speed sensor (VBOX III manufactured by Racelogic) was used to monitor the vehicle speed. Data from all tests is presented in the Appendix .
Technical Paper

Comprehensive Computational Rollover Sensitivity Study Part 2: Influence of Vehicle, Crash, and Occupant Parameters on Head, Neck, and Thorax Response

2011-04-12
2011-01-1115
Fatalities resulting from vehicle rollover events account for over one-third of all U.S. motor vehicle occupant fatalities. While a great deal of research has been directed towards the rollover problem, few studies have attempted to determine the sensitivity of occupant injury risk to variations in the vehicle (roof strength), crash (kinematic conditions at roof-to-ground contact), and occupant (anthropometry, position and posture) parameters that define the conditions of the crash. A two-part computational study was developed to examine the sensitivity of injury risk to changes in these parameters. The first part of this study, the Crash Parameter Sensitivity Study (CPSS), demonstrated the influence of parameters describing the vehicle and the crash on vehicle response using LS-DYNA finite element (FE) simulations.
Technical Paper

Rollover Testing of Recreational Off-Highway Vehicles (ROVs) for Accident Reconstruction

2011-04-12
2011-01-1117
This paper presents results of full-scale instrumented rollover testing on ROV type recreational vehicles. Five tests were conducted using two instrumented side-by-side ROVs at speeds between 20 and 32 mph on unpaved surfaces. Each test vehicle was brought to speed and released, allowing remote steering inputs to initiate turn sequences resulting in rollover. Accelerations were determined using x, y, and z axis accelerometers mounted at the vehicle CG and recorded using a robust data acquisition system. Roll rates were measured using a rotation rate sensor. Roll rates and key acceleration events are presented for each test. Mapping and measurement of the test site includes photography and digital survey of resulting tire marks, impact marks and gouging. Documentation and reconstruction of test roll sequences includes roll rates, vehicle positions and velocities, peak accelerations by impact, and scratch mark and damage examination. These are included in the appendix .
Journal Article

Design of a Dynamic Rollover Test System

2011-04-12
2011-01-1116
A dynamic rollover test system (DRoTS) capable of simulating rollover crashes in a laboratory was designed for research use at the University of Virginia. The goal of the current study is to describe the system's capabilities and specifications as well as to explore the limitations of the system's ability to simulate rollover crashes. The test apparatus was designed to permit simulation of a single roof-to-ground interaction of a rollover crash with the potential to be modified for evaluation of pre-roof contact occupant motion. Special considerations were made to permit testing of both dummies and post-mortem human surrogates in both production vehicles and a parametric test buck. DRoTS permits vertical translation, pitch, and roll of the test vehicle while constraining longitudinal and lateral translations and yaw. The study details the ranges of test parameters capable with the DRoTS and evaluates the limitations of the system relative to rollover crash conditions.
Journal Article

Effects of Safety Belt Pretensioning on ATD Motion in Rigid Fixture Rollover Testing

2011-04-12
2011-01-1118
General Motors conducted a series of subsystem rigid fixture sled rollover tests to evaluate the effects of various safety belt pyrotechnic pretensioners on Anthropomorphic Test Device (ATD) head motion. Twelve tests were conducted using a rigid fixture comprised of a modified compact sport utility vehicle (SUV) body encased in a rigid exoskeleton. The testing simulated the pre-trip/trip, free flight and first roof to ground impact phases of a field representative curb trip initiation rollover crash test with a roof to ground impact angle of approximately 180 degrees. Various combinations of safety belt lap anchor, buckle and retractor pretensioners were tested and film analysis was used to measure trailing side ATD head motion relative to the vehicle. Additionally, a new analysis technique of measuring the reduction of lap webbing length during the crash event was developed for evaluating the ability of a restraint system to reduce ATD head motion during the rollover tests.
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