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Technical Paper

Field-based Assessments of Various AIS2+ Head Risk Curves for Frontal Impact

2015-04-14
2015-01-1437
In the present study, various risk curves for moderate-to-fatal head injury (AIS2+) were theoretically assessed by comparing model-based injury rates with field-based injury rates. This was accomplished by applying the risk curves in corresponding field models. The resulting injury rates were considered from two perspectives: aggregate (0-56 kph events) and point-estimate (higher-speed, barrier-like events). Four risk curves were studied: a HIC15-based curve from Mertz et al. (1997), a BRIC-based curve from Takhounts et al. (2011), a BrIC-based curve from Takhounts et al. (2013) and a Concussion-Correlate-based curve from Rowson et al. (2013). The field modeling pertained to adult drivers in 11-1 o'clock, towaway, full-engagement frontal crashes in the National Automotive Sampling System (NASS, calendar years = 1993-2012), and the model-year range of the passenger vehicles was 1985-2010.
Technical Paper

Injury Distributions of Belted Drivers in Various Types of Frontal Impact

2015-04-14
2015-01-1490
Injury distributions of belted drivers in 1998-2013 model-year light passenger cars/trucks in various types of real-world frontal crashes were studied. The basis of the analysis was field data from the National Automotive Sampling System (NASS). The studied variables were injury severity (n=2), occupant body region (n=8), and crash type (n=8). The two levels of injury were moderate-to-fatal (AIS2+) and serious-to-fatal (AIS3+). The eight body regions ranged from head/face to foot/ankle. The eight crash types were based on a previously-published Frontal Impact Taxonomy (FIT). The results of the study provided insights into the field data. For example, for the AIS2+ upper-body-injured drivers, (a) head and chest injury yield similar contributions, and (b) about 60% of all the upper-body injured drivers were from the combination of the Full-Engagement and Offset crashes.
Journal Article

Modeling of an Advanced Steering Wheel and Column Assembly for Frontal and Side Impact Simulations

2014-04-01
2014-01-0803
This paper presents the final phase of a study to develop the modeling methodology for an advanced steering assembly with a safety-enhanced steering wheel and an adaptive energy absorbing steering column. For passenger cars built before the 1960s, the steering column was designed to control vehicle direction with a simple rigid rod. In severe frontal crashes, this type of design would often be displaced rearward toward the driver due to front-end crush of the vehicle. Consequently, collapsible, detachable, and other energy absorbing steering columns emerged to address this type of kinematics. These safety-enhanced steering columns allow frontal impact energy to be absorbed by collapsing or breaking the steering columns, thus reducing the potential for rearward column movement in severe crashes. Recently, more advanced steering column designs have been developed that can adapt to different crash conditions including crash severity, occupant mass/size, seat position, and seatbelt usage.
Journal Article

Modeling of Adaptive Energy Absorbing Steering Columns for Dynamic Impact Simulations

2014-04-01
2014-01-0802
The objective of this paper focused on the modeling of an adaptive energy absorbing steering column which is the first phase of a study to develop a modeling methodology for an advanced steering wheel and column assembly. Early steering column designs often consisted of a simple long steel rod connecting the steering wheel to the steering gear box. In frontal collisions, a single-piece design steering column would often be displaced toward the driver as a result of front-end crush. Over time, engineers recognized the need to reduce the chance that a steering column would be displaced toward the driver in a frontal crash. As a result, collapsible, detachable, and other energy absorbing steering columns emerged as safer steering column designs. The safety-enhanced construction of the steering columns, whether collapsible, detachable, or other types, absorb rather than transfer frontal impact energy.
Journal Article

Side Crash Pressure Sensor Prediction for Unitized Vehicles: An ALE Approach

2013-04-08
2013-01-0657
With a goal to help develop pressure sensor calibration and deployment algorithms using computer simulations, an Arbitrary Lagrangian Eulerian (ALE) approach was adopted in this research to predict the responses of side crash pressure sensors for unitized vehicles. For occupant protection, acceleration-based crash sensors have been used in the automotive industry to deploy restraint devices when vehicle crashes occur. With improvements in the crash sensor technology, pressure sensors that detect pressure changes in door cavities have been developed recently for vehicle crash safety applications. Instead of using acceleration (or deceleration) in the acceleration-based crash sensors, the pressure sensors utilize pressure change in a door structure to determine the deployment of restraint devices. The crash pulses recorded by the acceleration-based crash sensors usually exhibit high frequency and noisy responses.
Journal Article

Side Crash Pressure Sensor Prediction for Body-on-Frame Vehicles: An ALE Approach

2013-04-08
2013-01-0666
In an attempt to assist pressure sensor algorithm and calibration development using computer simulations, an Arbitrary Lagrangian Eulerian (ALE) approach was adopted in this study to predict the responses of side crash pressure sensors for body-on-frame vehicles. Acceleration based, also called G-based, crash sensors have been used extensively to deploy restraint devices, such as airbags, curtain airbags, seatbelt pre-tensioners, and inflatable seatbelts, in vehicle crashes. With advancements in crash sensor technologies, pressure sensors that measure pressure changes in vehicle side doors have been developed recently and their applications in vehicle crash safety are increasing. The pressure sensors are able to detect and record the dynamic pressure change when the volume of a vehicle door changes as a result of a crash.
Journal Article

Side Crash Pressure Sensor Prediction: An Improved Corpuscular Particle Method

2012-04-16
2012-01-0043
In an attempt to predict the responses of side crash pressure sensors, the Corpuscular Particle Method (CPM) was adopted and enhanced in this research. Acceleration-based crash sensors have traditionally been used extensively in automotive industry to determine the air bag firing time in the event of a vehicle accident. The prediction of crash pulses obtained from the acceleration-based crash sensors by using computer simulations has been very challenging due to the high frequency and noisy responses obtained from the sensors, especially those installed in crash zones. As a result, the sensor algorithm developments for acceleration-based sensors are largely based on prototype testing. With the latest advancement in the crash sensor technology, side crash pressure sensors have emerged recently and are gradually replacing acceleration-based sensor for side impact applications.
Journal Article

Side Crash Pressure Sensor Prediction: An ALE Approach

2012-04-16
2012-01-0046
An Arbitrary Lagrangian Eulerian (ALE) approach was adopted in this study to predict the responses of side crash pressure sensors in an attempt to assist pressure sensor algorithm development by using computer simulations. Acceleration-based crash sensors have traditionally been used to deploy restraint devises (e.g., airbags, air curtains, and seat belts) in vehicle crashes. The crash pulses recorded by acceleration-based crash sensors usually exhibit high frequency and noisy responses depending on the vehicle's structural design. As a result, it is very challenging to predict the responses of acceleration-based crash sensors by using computer simulations, especially those installed in crush zones. Therefore, the sensor algorithm developments for acceleration-based sensors are mostly based on physical testing.
Technical Paper

Archetypal Vehicle Dynamics Model for Resistance Rollover Prediction

2010-04-12
2010-01-0715
Nowadays is a common sense the importance of the CAE usage in the modern automotive industry. The ability to predict the design behavior of a project represents a competitive advantage. However, some CAE models have become so complex and detailed that, in some cases, one just can not build up the model without a considerable amount of information. In that case simplified models play an important role in the design phase, especially in pre-program stages. This work intends to build an archetypal vehicle dynamics model able to predict the rollover resistance of a vehicle design. Through the study of a more complex model, carried out in Adams environment, it was possible to identify the key degrees of freedom to be considered in the simplified model along with important elements of the suspension which are also important design factors.
Technical Paper

Passive Safety Technologies and Belted ATD Neck Loads in Rollover Events

2010-04-12
2010-01-1008
Two rigid rollover test devices were constructed to have the approximate dimensions, mass and inertial properties of a mid-sized Car and Sport Utility Vehicle (SUV). The rigid devices were used to generate vehicle and occupant responses from a series of laboratory rollover tests. For each rigid rollover test, a deceleration sled was used to subject each rigid vehicle to nearly identical lateral speeds and decelerations. The rigid vehicles were limited to a single roll by tethering the vehicles to the deceleration cart. The vehicle's roll rate, roll angle, lateral acceleration and Anthropomorphic Test Devices (ATD) neck responses generated from the rigid SUV were compared to the responses of a full vehicle production SUV under similar test conditions. The rigid SUV and Car devices were then used to examine the effects of activating safety belt pre-tensioning systems and roof mounted side curtain airbags at various times on ATD neck forces and moments.
Technical Paper

Thoracic Response of Belted PMHS, the Hybrid III, and the THOR-NT Mid-Sized Male Surrogates in Low-Speed, Frontal Crashes

2006-11-06
2006-22-0009
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.
Technical Paper

A Theoretical Math Model for Projecting Ais3+ Thoracic Injury for Belted Occupants in Frontal Impacts

2004-11-01
2004-22-0020
A theoretical math model was created to assess the net effect of aging populations versus evolving system designs from the standpoint of thoracic injury potential. The model was used to project the next twenty-five years of thoracic injuries in Canada. The choice of Canada was topical because rulemaking for CMVSS 208 has been proposed recently. The study was limited to properly-belted, front-outboard, adult occupants in 11-1 o'clock frontal crashes. Moreover, only AIS3+thoracic injury potential was considered. The research consisted of four steps. First, sub-models were developed and integrated. The sub-models were made for numerous real-world effects including population growth, crash involvement, fleet penetration of various systems (via system introduction, vehicle production, and vehicle attrition), and attendant injury risk estimation. Second, existing NASS data were used to estimate the number of AIS3+ chest-injured drivers in Canada in 2001.
Technical Paper

Finite element simulation of drive shaft in truck/SUV frontal crash

2001-06-04
2001-06-0106
Drive shaft modelling effects frontal crash finite element simulation. A 35 mph rigid barrier impact of a body on frame SUV with an one piece drive shaft and a unibody SUV with a two piece drive shaft have been studied and simulated using finite element analyses. In the model, the drive shaft can take significant load in frontal impact crash. Assumptions regarding the drive shaft model can change the predicted engine motion in the simulation. This change influences the rocker @ B-pillar deceleration. Two modelling methods have been investigated in this study considering both joint mechanisms and material failure in dynamic impact. Model parameters for joint behavior and failure should be determined from vehicle design information and component testing. A body on frame SUV FEA model has been used to validate the drive shaft modeling technique by comparing the simulation results with crash test data.
Technical Paper

Assessment of Magnetohydrodynamic Angular Rate Sensors in Measuring Ankle Rotations During Vehicle's Crash Tests

2000-03-06
2000-01-0609
While testing vehicles for crash, particularly the offset frontal crash mode, new devices and techniques are needed to enhance the ability to measure rotations of certain vehicle components and dummy parts (or joints). The reason for this new demand is that the capabilities of existing techniques or devices in measuring rotations of small masses in confined areas are limited. Examples of the desired measurements are the rotations of dummy's feet and tibias as well as the rotations of the vehicle's toe-board during intrusion. These measurements help to understand dummy's ankle loads as a result of different intrusion rates. Furthermore, having these measurements is very beneficial to the validation of the computer models used in simulating the behavior of dummy's lower extremities in high intrusion crashes. Recent research demonstrated the use of an angular rate sensor, based on magnetohydrodynamic principles, on Hybrid-III dummies and cadavers.
Technical Paper

Prediction of Front TTI in NHTSA Side Impact Using a Regression-Based Approach

2000-03-06
2000-01-0636
Vehicle side impact performance is potentially affected by a large number of parameters which may be related to body stiffness and energy absorption characteristics, and packaging dimensions. An understanding of the principal variables controlling TTI (Thoracic Trauma Index) is fundamental to the achievement of high LINCAP (Lateral Impact New Car Assessment Program) rating especially for sedans. In the present study, the effects on TTI of the following are considered: response-related parameters such as velocity and intrusion (which are in turn related to body structure), countermeasures such as side airbag, and dummy to structure clearance dimensions. With the help of test data gathered from side impact tests carried out on cars and trucks at Ford, a new “best subset” regression model is developed and is shown to be able to predict TTI for a number of LINCAP tests which were not part of the suite used in the derivation of the model.
Technical Paper

Investigating Ankle Injury Mechanisms in Offset Frontal Collisions Utilizing Computer Modeling and Case-Study Data

1999-10-10
99SC14
A significant number of documented ankle injuries incurred in automobile accidents indicate some form of lateral loading is present to either cause or influence injury. A high percentage of these cases occur in the absence of occupant compartment intrusion. To date, no specific ankle injury mechanism has been identified to explain these types of injuries. To investigate this problem, several resources were used including full-scale crash test data, finite element models, and case study field data. Results from car-to-car, offset frontal crash tests indicate a significant lateral acceleration (10-18 g) occurs at the same time as the peak in longitudinal acceleration. The combined loading condition results in a significant lateral force being applied to the foot-ankle region while the leg region is under maximum compression.
Technical Paper

A New Component Test Methodology Concept for Side Impact Simulation

1999-03-01
1999-01-0427
This paper describes the development of a new component test methodology concept for simulating NHTSA side impact, to evaluate the performance of door subsystems, trim panels and possible safety countermeasures (foam padding, side airbags, etc.). The concept was developed using MADYMO software and the model was validated with a DOT-SID dummy. Moreover, this method is not restricted to NHTSA side impact, but can be also be used for simulating the European procedure, with some modifications. This method uses a combination of HYGE and VIA decelerator to achieve the desired door velocity profile from onset of crash event until door-dummy separation, and also takes into account the various other factors such as the door/B pillar-dummy contact velocity, door compliance, shape of intruding side structure, seat-to-door interaction and initial door-dummy distance.
Technical Paper

Finite Element Simulation of the EEVC Offset Deformable Barrier

1997-04-08
971531
Statistic shows the majority of real world frontal collisions involve only partial overlap of the vehicle front end. Thus the European Experimental Vehicle Committee (EEVC) has established a safety standard and test procedure utilizing a deformable barrier for offset impacts. The offset deformable barrier (ODB) is designed to represent the characteristics of a vehicle front end. Therefore, it can replace a target vehicle and the offset test can be conducted economically. Many component, sub-assembly and full vehicle system tests have been conducted in Ford using the EEVC ODB. Based on the various tests, the barrier responds differently depending on the front end design and the size of an impacting vehicle. Sometimes the front end of a test vehicle punches through the barrier. Also rupture of aluminum sheets and tearing of honeycomb materials are often observed in post-test barriers.
Technical Paper

Intrusion Factors and Their Effects on Steering Column Movements During Vehicle's Frontal Impact Testing

1997-02-24
970573
Significant dashpanel intrusion is seen in some cars after severe frontal crashes at high speeds or after offset impact with rigid barrier or both. This intrusion may also result in severe steering column displacements and rotation. Knowledge of both responses is critical for designing an efficient vehicle front end that will respond well in crash. The intrusion has an effect on deciding the car front end length, while the column movements have an effect on the driver dummy's response. For reasons of developing efficiency and safety in vehicles and due to lack of published research, studies were conducted to understand the nature of the intrusion phenomenon as well as the mechanics of the steering column movement in the presence of intrusion. This paper describes an experimental investigation on intrusion and steering column movements.
Technical Paper

Development of a Door Test Facility for Implementing the Door Component Test Methodology

1997-02-24
970568
This paper describes the development of an automated Door Test Facility for implementing the Door Component Test Methodology for side impact analysis. The automated targeting and loading of the door inner/trim panels with Side Impact Dummy (SID) ribcage, pelvis, and leg rams will greatly improve its test-to-test repeatability and expedite door/trim/armrest development/evaluation for verification with the dynamic side impact test of FMVSS 214 (Occupant Side Impact Protection). This test facility, which is capable of evaluating up to four (4) doors per day, provides a quick evaluation of door systems. The results generated from this test methodology provide accurate input data necessary for a MADYMO Side Impact Simulation Model. The test procedure and simulation results will be discussed.
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