Rear Seated Child Injury Risk Experimental Measures Related to Vehicle Front Seat Performance in Rear Impacts

2009 ◽  
Author(s):  
Kenneth J. Saczalski ◽  
Mark C. Pozzi ◽  
Joseph Lawson Burton
Keyword(s):  
Risk Assessment ◽  
Injury Risk ◽  
Crash Test ◽  
Front Seat ◽  
Child Injury ◽  
Vehicle Type ◽  
Rear Impact ◽  
Study Results ◽  
Statistical Studies ◽  
Rear Impacts

Recent field accident statistical studies dealing with injury risk assessment of rear seated children in rear impacts indicated a doubling of AIS 2+ injuries when front seats deformed, and a 61 percent increase in fatal injury for rear-seated children, as compared to front-seated children, in rear impacts. Several interrelated factors, which influence child injury risk in rear impacts, were not evaluated in these field accident statistical studies. These factors include: rear-impact severity levels; front occupant sizes; front seat strength variations and protection levels; vehicle type; (i.e. minivan, sedan, etc.); rear child sizes; and, rear child restraint types. This current study uses an experimental “multi-variable” crash test approach, and “inferred statistical” methodology, to scientifically evaluate the several key factors that effect rear child injury risk in rear impacts. This “multi-variable” methodology was previously utilized by the authors for study of front-seated adult injury risk assessment. Various sizes of rear child surrogates (i.e. 6 month-old up to the 6 year-old Hybrid III size), located behind different sizes of front adult surrogates (i.e. small 50kg female up to larger male surrogates ballasted to 110kg) seated in different strength front seats, were dynamically tested at rear-impact severity speed change levels ranging from about 20 to 50 kph. Both sled-body-buck and full vehicle crash tests were used in this study. Front seat strength levels ranged from the weaker 3.2kN level for single recliner (SR) seats, without belts attached to the seatback, up to the stronger belt-integrated seat (BIS) levels of about 14.7kN. The study results demonstrate that, even absent rear crush intrusion, the easily deforming SR front seats pose a high risk of injury to the rear child, regardless of vehicle type, in contrast to stronger and safer BIS designs.

scholarly journals Design and Evaluation of the Initial 50th Percentile Female Prototype Rear Impact Dummy, BioRID P50F – Indications for the Need of an Additional Dummy Size

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna Carlsson ◽  
Johan Davidsson ◽  
Astrid Linder ◽  
Mats Y. Svensson
Keyword(s):  
Angular Displacement ◽  
Crash Test ◽  
Head Restraint ◽  
Response Data ◽  
Rear Impact ◽  
Protection Systems ◽  
Crash Test Dummy ◽  
Rear Impacts ◽  
Lumbar Spinal ◽  
Head Neck

The objective of this study was to present the design of a prototype rear impact crash test dummy, representing a 50th percentile female, and compare its performance to volunteer response data. The intention was to develop a first crude prototype as a first step toward a future biofidelic 50th percentile female rear impact dummy. The current rear impact crash test dummy, BioRID II, represents a 50th percentile male, which may limit the assessment and development of whiplash protection systems with regard to female occupants. Introduction of this new dummy size will facilitate evaluation of seat and head restraint (HR) responses in both the average sized female and male in rear impacts. A 50th percentile female rear impact prototype dummy, the BioRID P50F, was developed from modified body segments originating from the BioRID II. The mass and rough dimensions of the BioRID P50F is representative of a 50th percentile female. The prototype dummy was evaluated against low severity rear impact sled tests comprising six female volunteers closely resembling a 50th percentile female with regard to stature and mass. The head/neck response of the BioRID P50F prototype resembled the female volunteer response corridors. The stiffness of the thoracic and lumbar spinal joints remained the same as the average sized male BioRID II, and therefore likely stiffer than joints of an average female. Consequently, the peak rearward angular displacement of the head and T1, and the rearward displacement of the T1, were lesser for the BioRID P50F in comparison to the female volunteers. The biofidelity of the BioRID P50F prototype thus has some limitations. Based on a seat response comparison between the BioRID P50F and the BioRID II, it can be concluded that the male BioRID II is an insufficient representation of the average female in the assessment of the dynamic seat response and effectiveness of whiplash protection systems.

Head-turned rear impact causing dynamic cervical intervertebral foramen narrowing: implications for ganglion and nerve root injury

2006 ◽  
Vol 4 (5) ◽  
pp. 380-387 ◽  
Author(s):  
Yasuhiro Tominaga ◽  
Travis G. Maak ◽  
Paul C. Ivancic ◽  
Manohar M. Panjabi ◽  
Bryan W. Cunningham
Keyword(s):  
Nerve Root ◽  
Injury Risk ◽  
Compression Injury ◽  
Nerve Root Injury ◽  
Rear Impact ◽  
Cervical Ganglion ◽  
Spine Model ◽  
Continuous Dynamic ◽  
Rear Impacts ◽  
The Right

Object A rotated head posture at the time of vehicular rear impact has been correlated with a higher incidence and greater severity of chronic radicular symptoms than accidents occurring with the occupant facing forward. No studies have been conducted to quantify the dynamic changes in foramen dimensions during head-turned rear-impact collisions. The objectives of this study were to quantify the changes in foraminal width, height, and area during head-turned rear-impact collisions and to determine if dynamic narrowing causes potential cervical nerve root or ganglion impingement. Methods The authors subjected a whole cervical spine model with muscle force replication and a surrogate head to simulated head-turned rear impacts of 3.5, 5, 6.5, and 8 G following a noninjurious 2-G baseline acceleration. Continuous dynamic foraminal width, height, and area narrowing were recorded, and peaks were determined during each impact; these data were then statistically compared with those obtained at baseline. The authors observed significant increases (p < 0.05) in mean peak foraminal width narrowing values greater than baseline values, of up to 1.8 mm in the left C5–6 foramen at 8 G. At the right C2–3 foramen, the mean peak dynamic foraminal height was significantly narrower than baseline when subjected to rear-impacts of 5 and 6.5 G, but no significant increases in foraminal area were observed. Analysis of the results indicated that the greatest potential for cervical ganglion compression injury existed at C5–6 and C6–7. Greater potential for ganglion compression injury existed at C3–4 and C4–5 during head-turned rear impact than during head-forward rear impact. Conclusions Extrapolation of present results indicated potential ganglion compression in patients with a non-stenotic foramen at C5–6 and C6–7; in patients with a stenotic foramen the injury risk greatly increases and spreads to include the C3–4 through C6–7 as well as C4–5 through C6–7 nerve roots.

Study of Seat System Performance Related to Injury of Rear Seated Children and Infants in Rear Impacts

2002 ◽  
Author(s):  
Kenneth J. Saczalski ◽  
Joseph Lawson Burton ◽  
Paul R. Lewis ◽  
Keith Friedman ◽  
Todd K. Saczalski
Keyword(s):  
Injury Risk ◽  
Rear Seat ◽  
Motor Vehicles ◽  
Front Seat ◽  
Vehicle To Vehicle ◽  
Booster Seats ◽  
Child Restraint ◽  
Speed Change ◽  
Serious Injury ◽  
Rear Impacts

Since 1996 the NHTSA has warned of the airbag deployment injury risk to front seated children and infants, during frontal impact, and they have recommended that children be placed in the rear seating areas of motor vehicles. However, during most rear impacts the adult occupied front seats will collapse into the rear occupant area and, as such, pose another potentially serious injury risk to the rear seated children and infants who are located on rear seats that are not likely to collapse. Also, in the case of higher speed rear impacts, intrusion of the occupant compartment may cause the child to be shoved forward into the rearward collapsing front seat occupant thereby increasing impact forces to the trapped child. This study summarizes the results of more than a dozen actual accident cases involving over 2-dozen rear-seated children, where 7 children received fatal injuries, and the others received injuries ranging from severely disabling to minor injury. Types of injuries include, among others: crushed skulls and brain damage; ruptured hearts; broken and bruised legs; and death by post-crash fires when the children became entrapped behind collapsed front seat systems. Several rear-impact crash tests, utilizing sled-bucks and vehicle-to-vehicle tests, are used to examine the effects of front seat strength and various types of child restraint systems, such as booster seats and child restraint seats (both forward and rearward facing), in relation to injury potential of rear seated children and infants. The tests utilized sedan and minivan type vehicles that were subjected to speed changes ranging from about 20 to 50 kph (12 to 30 mph), with an average G level per speed change of about 9 to 15. The results indicate that children and infants seated behind a collapsing driver seat, even in low severity rear impacts of less than 25 kph, encounter a high risk of serious or fatal injury, whether or not rear intrusion takes place. Children seated in other rear seat positions away from significant front seat collapse, such as behind the stronger “belt-integrated” types of front seats or rearward but in between occupied collapsing front seat positions, are less likely to be as seriously injured.

Comparison of High and Low Speed Rear-Impact Head and Neck Injury Risk Measures Related to Occupant Size and Vehicle Seat Strength Characteristics

2008 ◽  
Author(s):  
Kenneth J. Saczalski ◽  
Mark C. Pozzi ◽  
Joseph Lawson Burton
Keyword(s):  
Head And Neck ◽  
Injury Risk ◽  
Risk Measures ◽  
Neck Injury ◽  
Child Injury ◽  
Small Female ◽  
Factorial Method ◽  
Rear Impact ◽  
Hybrid Iii ◽  
Head And Neck Injury

This study demonstrates the use of efficient inferred statistical “factorial methods” for scientifically evaluating, with a relatively few tests, the rear-impact occupant “head and neck injury risk” performance of 2 different types of vehicle front seats, with adjustable headrests, when various size occupants are subjected to high and low impact severities. The 2 seat types studied included the stronger “belt-integrated seat” (BIS) designs, with restraints attached and having strength levels beyond 14 kN, and the more common but weaker single recliner (SR) seats, without attached restraints and having only about 3.2 kN strength. Sled-body-buck systems and full vehicle to barrier tests were run with “matched pairs” of surrogates in the 2 seat types at speed changes of 12.5 to 50 kph. Three sizes of Hybrid-III adult surrogates (i.e. 52 kg small female, 80 kg average male, and an average male surrogate ballasted to about 110 kg) were used in the evaluations. Also, some tests were run with 6 year-old Hybrid-III child surrogates located behind the front seats due to interest in potential child injury from collapsing front seats. The 2-level factorial method, combined with a biomechanical ratio comparison and a “student-t” test evaluation, were used to compare safety performance of the 2 seat designs. The resulting data analysis indicates that, in the mid to high range of rear impact severity (i.e. 20 to 50 kph), the stronger BIS seat systems tend to provide greatly improved “head-neck” protection over the weaker SR type seats for both the front seated adult occupants and rear seated children. At the low range of impact severity (i.e. 12.5 to 19 kph) there was no significant statistical difference between either seat types, except that the headrests of both could be improved.

scholarly journals Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

2021 ◽  
Vol 18 (6) ◽  
pp. 2901
Author(s):  
Paul S. Nolet ◽  
Larry Nordhoff ◽  
Vicki L. Kristman ◽  
Arthur C. Croft ◽  
Maurice P. Zeegers ◽  
...  
Keyword(s):  
Real World ◽  
Injury Risk ◽  
Angular Acceleration ◽  
Traffic Crashes ◽  
Rear Impact ◽  
Comparative Review ◽  
Minimal Damage ◽  
Injury Causation ◽  
Crash Tests ◽  
Biomechanical Approach

Injury claims associated with minimal damage rear impact traffic crashes are often defended using a “biomechanical approach,” in which the occupant forces of the crash are compared to the forces of activities of daily living (ADLs), resulting in the conclusion that the risk of injury from the crash is the same as for ADLs. The purpose of the present investigation is to evaluate the scientific validity of the central operating premise of the biomechanical approach to injury causation; that occupant acceleration is a scientifically valid proxy for injury risk. Data were abstracted, pooled, and compared from three categories of published literature: (1) volunteer rear impact crash testing studies, (2) ADL studies, and (3) observational studies of real-world rear impacts. We compared the occupant accelerations of minimal or no damage (i.e., 3 to 11 kph speed change or “delta V”) rear impact crash tests to the accelerations described in 6 of the most commonly reported ADLs in the reviewed studies. As a final step, the injury risk observed in real world crashes was compared to the results of the pooled crash test and ADL analyses, controlling for delta V. The results of the analyses indicated that average peak linear and angular acceleration forces observed at the head during rear impact crash tests were typically at least several times greater than average forces observed during ADLs. In contrast, the injury risk of real-world minimal damage rear impact crashes was estimated to be at least 2000 times greater than for any ADL. The results of our analysis indicate that the principle underlying the biomechanical injury causation approach, that occupant acceleration is a proxy for injury risk, is scientifically invalid. The biomechanical approach to injury causation in minimal damage crashes invariably results in the vast underestimation of the actual risk of such crashes, and should be discontinued as it is a scientifically invalid practice.

Injury risk assessment based on pre-crash variables: The role of closing velocity and impact eccentricity

2021 ◽  
Vol 150 ◽  
pp. 105864
Author(s):  
Michelangelo-Santo Gulino ◽  
Leonardo Di Gangi ◽  
Alessio Sortino ◽  
Dario Vangi
Keyword(s):  
Risk Assessment ◽  
Injury Risk

The relationship of seat backrest angle and neck injury in low-velocity rear impacts

2005 ◽  
Vol 219 (11) ◽  
pp. 1293-1302 ◽  
Author(s):  
J Latchford ◽  
E C Chirwa ◽  
T Chen ◽  
M Mao
Keyword(s):  
Close Correlation ◽  
Neck Injury ◽  
Low Velocity ◽  
Cervical Spine Injuries ◽  
Rear Impact ◽  
Test Specifications ◽  
Lower Neck ◽  
Rear Impacts ◽  
Relationship Of ◽  
The Relationship

Car-rear-impact-induced cervical spine injuries present a serious burden on society and, in response, seats offering enhanced protection have been introduced. Seats are evaluated for neck protection performance but only at one specific backrest angle, whereas in the real world this varies greatly owing to the variation in occupant physique. Changing the backrest angle modifies the seat geometry and thereby the nature of its interaction with the occupant. Low-velocity rear-impact tests on a BioRID II anthropomorphic test dummy (ATD) have shown that changes in backrest angle have a significant proportionate effect on dummy kinematics. A close correlation was found between changes in backrest angle and the responses of neck injury predictors such as lower neck loading and lower neck shear but not for the neck injury criterion NICmax. Torso ramping was evident, however, with negligible effect in low-velocity impacts. The backrest angle ranged from 20° to 30° whereas the BioRID II spine was adapted to a range from 20° to 26.5°. Nevertheless, in general, instrumentation outputs correlated well, indicating that this ATD could be used for evaluating seats over a 20–30° range rather than solely at 25° as required by current approval test specifications.

scholarly journals Risk assessment of ice dams for water diversion projects based on fuzzy fault trees

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Mengkai Liu ◽  
Xiaoxia Dong ◽  
Hui Guo
Keyword(s):  
Risk Assessment ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Northern China ◽  
Indicator System ◽  
Water Diversion ◽  
Risk Indicators ◽  
Scoring Method ◽  
Study Results ◽  
Dam Risk

AbstractIce dams are among the important risks affecting the operational safety and water conveyance efficiency of water diversion projects in northern China. However, no evaluation indicator system for ice dam risk assessment of water diversion projects has been proposed. Therefore, in this paper, based on the formation mechanism of ice dams, the risk assessment indicator system and the possibility calculation model of ice dams were both proposed for water diversion projects based on the fuzzy fault tree analysis method. The ice dam risk fault tree constructed in this study mainly includes three aspects: ice production, ice transport, and ice submergence conditions. Eighteen basic risk indicators were identified, and 72 minimum cut sets were obtained by using the mountain climb method. Eight risk indicators were determined as the key risk indicators for ice dams, including meteorological conditions, narrowed cross section, sluice incident, erroneous scheduling judgment, ice cover influence, flat bed slope, control structures, and ice flow resistance of piers. Then, the canal from the Fenzhuanghe sluice to the Beijumahe sluice of the Middle Route of the South-to-North Water Diversion Project was taken as the research object. Combined with the expert scoring method, the ice dam risk probability of the canal was determined to be 0.2029 × 10−2, which was defined as a level III risk, which is an occasionally occurring risk. The study results can support ice dam risk prevention and canal system operation in winter for water diversion projects.

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