Far-side Occupant Research Articles

Interaction between multiple convertible child restraint systems and pediatric occupants in oblique impacts

Objectives To assess the interaction of multiple rearward-facing (RF) and forward-facing (FF) CRS restrained pediatric occupants on their kinetics in oblique impacts. Methods A Q3s and a Q1.5 ATD were restrained in 2 CRSs of varying widths—standard (503mm) and slim-fit (425mm)—in the 2 rear outboard seats of a 2023 compact sedan rigidized rear seat bench. A surrogate door structure was mounted at the left outboard location. The Q1.5 was seated in an RF configuration, and the Q3s was seated in RF or FF configurations across tests. The ATDs were restrained as follows: (1) both ATDs in standard CRSs and (2) both ATDs in slim-fit CRSs, switching between the outboard seats for a total of 8 conditions. The condition with the highest head kinetic metrics from these tests was reproduced in a ninth test with the rear seat’s center armrest lowered between CRSs. The entire environment was subjected to an oblique impact at 60° using the FMVSS 213 impact pulse. Results The Q3s’ head contacted the nearby CRS shell when seated farside. When seated nearside, the Q3s’ head contacted the surrogate door structure in 1 of 4 conditions. The Q1.5’s head contacted the nearby CRS in 2 of 4 conditions when seated farside. The Q3s when seated RF had higher HIC15 and head 3ms clip acceleration (H3ms), regardless of farside or nearside position. When seated farside, upper neck tensile force (Fz) for the Q3s in FF configuration (2,317.4 and 2,077.9 N) was higher than that in RF configuration (1,850.8 and 1,802.8 N). When seated nearside, the same in FF configuration (701.3 and 1,029.4 N) was lower than that in RF configuration (997.6 and 1,261.7 N). Repeating the condition with the highest head kinetic metrics (HIC15 = 1246; H3ms = 114.4 g) but lowering the center armrest between the CRSs resulted in lower head kinetic metrics (HIC15 = 916, H3ms = 93.5 g). Conclusions In most cases, the farside seated ATD’s head contacted the nearside CRS shell, resulting in elevated injury metric numbers and higher loading in both CRS types. The nearside ATD did not experience detrimental effects of the interaction with the farside occupant and CRS.

Characterization of far-side occupant chest injuries in oblique side impact considering uncertainty

Purpose Oblique side impact is a common form of impact in life, and the far-side occupant’s chest is highly susceptible to injury in the impact process. This study analyzed the effects of different factors on the chest response of far-side occupants in oblique side impacts. Methods In this study, a simplified sled model was developed. After that, five factors, namely, impact velocity, impact angle, seat friction coefficient, seatbelt friction coefficient, and seatbelt force-limiting were considered as uncertain variables and randomly sampled. Sixteen sets of impact simulations with different parameters were performed using the sampled results to evaluate the farside occupant chest response. Results Results showed that the impact velocity was positively correlated with the chest deflection and chest acceleration, with correlation coefficients 0.77 and 0.92, respectively, and the impact angle was negatively correlated with the chest deflection and chest acceleration, with correlation coefficients -0.83 and -0.54, respectively. The seatbelt friction coefficient and force limiting value were positively and negatively correlated with the occupant’s chest response, respectively. Conclusions The results suggested that multiple variables collectively influenced occupant injury, and random combinations of different variables may play a critical role in impact outcomes. This study provides a reference for the study of occupant injury in far-side impacts.

Analysis of characteristics about far-side occupant’s chest injury during oblique side impact

The chest is one of the most frequently injured body parts during a side impact. In this study, the effects of impact angle, impact speed, and D-ring position on the occupant’s chest injury in the far-side crash were analyzed. First, a model with a sled and a Test Human Occupant Restraint (THOR) dummy was established. Second, the acceleration curves with peaks of 6.6 and 9.0 g were applied to the sled. Then 12 sets of simulations with different impact angles and D-ring positions were conducted to evaluate the occupant’s chest responses. Results indicate that the peak chest deflection at Lower Left (LL) decreased by 11.6% on average, and that at Lower Right (LR) increased by 11.7% on average when the D-ring position moved backward. Meanwhile, with the D-ring position moving upward, the peak chest deflection at LL grew by 24.8% on average, while it decreased by 14.7% at LR.

THOR dummy chest deflection response in oblique and lateral far-side sled tests

Objective: The focus of this study is side impact. Though occupant injury assessment and protection in nearside impacts has received considerable attention and safety standards have been promulgated, field studies show that a majority of far-side occupant injuries are focused on the head and thorax. The 50th percentile male Test Device for Human Occupant Restraint (THOR) has been used in oblique and lateral far-side impact sled tests, and regional body accelerations and forces and moments recorded by load cells have been previously reported. The aim of this study is to evaluate the chestband-based deflection responses from these tests.Methods: The 3-point belt–restrained 50th percentile male THOR dummy was seated upright in a buck consisting of a rigid flat seat, simulated center console, dashboard, far-side side door structure, and armrest. It was designed to conduct pure lateral and oblique impacts. The center console, dashboard, simulated door structure, and armrest were covered with energy-absorbing materials. A center-mounted airbag was mounted to the right side of the seat. Two 59-gage chestbands were routed on the circumference of the thorax, with the upper and lower chestbands at the level of the third and sixth ribs, respectively, following the rib geometry. Oblique and pure lateral far-side impact tests with and without airbags were conducted at 8.3 m/s. Maximum chest deflections were computed by processing temporal contours using custom software and 3 methods: Procedures paralleling human cadaver studies, using the actual anchor point location and actual alignment of the InfraRed Telescoping Rods for the Assessment of Chest Compression (IR-TRACC) in the dummy on each aspect—that is, right or left,—and using the same anchor location of the internal sensor but determining the location of the peak chest deflection on the contour confined to the aspect of the sensor; these were termed the SD, ID, and TD metrics, respectively.Results: All deformation contours at the upper and lower thorax levels and associated peak deflections are given for all tests. Briefly, the ID metrics were the lowest in magnitude for both pure lateral and oblique modes, regardless of the presence or absence of an airbag. This was followed by the TD metric, and the SD metric produced the greatest deflections.Conclusion: The chestbands provide a unique opportunity to compute peak deflections that parallel current IR-TRACC-type deflections and allow computation of peak deflections independent of the initial point of attachment to the rib. The differing locations of the peak deflection vectors along the rib contours for different test conditions suggest that a priori attachment is less effective. Further, varying magnitudes of the differences between ID and TD metrics underscore the difficulty in extrapolating ID outputs under different conditions: Pure lateral versus oblique, airbag presence, and thoracic levels. Deflection measurements should, therefore, not be limited to an instrument that can only track from a fixed point. For improved predictions, these results suggest the need to investigate alternative techniques, such as optical methods to improve chest deflection measurements for far-side occupant injury assessment and mitigation.

Far-side occupant responses based on current US side-impact protocol using finite element human body models

Most of the applied vehicle side-impact occupant protection research to date has concentrated on near-side occupants. Currently, no regulation exists in North America for the far-side occupant protection. Real-world crash data has shown that occupants seated on the non-struck side, defined as 'far-side' occupants, are still subjected to a risk of injuries. The objective of this study is to investigate body responses for the far-side occupant using current US side impact protocols. Current side impact protocol in the USA is designed to meet side Moving Deformable Barrier (MDB) and fixed oblique pole impact. Two seating cases are addressed; the first case consisted of a far-side occupant in the first row (single occupant) to evaluate the interaction of the occupant to the structure. The second case, a near-side occupant, was added to the far-side occupant (two occupants in a row) to study the interaction of the occupant-to-occupant. A finite element human body model (50th male) was used as a far-side and near-side occupant. Simulation results indicated that the LINCAP barrier could potentially produce the significant head rotational acceleration and thoracic rib deflection if the far-side occupant was included in the existing near-side crash protocols.

Far-side occupant responses based on current US side-impact protocol using finite element human body models

Most of the applied vehicle side-impact occupant protection research to date has concentrated on near-side occupants. Currently, no regulation exists in North America for the far-side occupant protection. Real-world crash data has shown that occupants seated on the non-struck side, defined as 'far-side' occupants, are still subjected to a risk of injuries. The objective of this study is to investigate body responses for the far-side occupant using current US side impact protocols. Current side impact protocol in the USA is designed to meet side Moving Deformable Barrier (MDB) and fixed oblique pole impact. Two seating cases are addressed; the first case consisted of a far-side occupant in the first row (single occupant) to evaluate the interaction of the occupant to the structure. The second case, a near-side occupant, was added to the far-side occupant (two occupants in a row) to study the interaction of the occupant-to-occupant. A finite element human body model (50th male) was used as a far-side and near-side occupant. Simulation results indicated that the LINCAP barrier could potentially produce the significant head rotational acceleration and thoracic rib deflection if the far-side occupant was included in the existing near-side crash protocols.

Assessment of Bilateral Thoracic Loading on the Near-Side Occupant Due to Occupant-to-Occupant Interaction in Vehicle Crash Tests

Objective: This study aims, by means of the WorldSID 50th percentile male, to evaluate thoracic loading and injury risk to the near-side occupant due to occupant-to-occupant interaction in combination with loading from an intruding structure.Method: Nine vehicle crash tests were performed with a 50th percentile WorldSID male dummy in the near-side (adjacent to the intruding structure) seat and a THOR or ES2 dummy in the far-side (opposite the intruding structure) seat. The near-side seated WorldSID was equipped with 6 + 6 IR-Traccs (LH and RH) in the thorax/abdomen enabling measurement of bilateral deflection. To differentiate deflection caused by the intrusion, and the deflection caused by the neighboring occupant, time history curves were analyzed. The crash tests were performed with different modern vehicles, equipped with thorax side airbags and inflatable curtains, ranging from a compact car to a large sedan, and in different loading conditions such as car-to-car, barrier, and pole tests. Lateral delta V based on vehicle tunnel acceleration and maximum residual intrusion at occupant position were used as a measurement of crash severity to compare injury measurements.Result: In the 9 vehicle crash tests, thoracic loading, induced by the intruding structure as well as from the far-side occupant, varied due to the size and structural performance of the car as well as the severity of the crash. Peak deflection on the thoracic outboard side occurred during the first 50 ms of the event. Between 70 to 150 ms loading induced by the neighboring occupant occurred and resulted in an inboard-side peak deflection and viscous criterion. In the tests where the target vehicle lateral delta V was below 30 km/h and intrusion less than 200 mm, deflections were low on both the outboard (20–40 mm) and inboard side (10–15 mm). At higher crash severities, delta V 35 km/h and above as well as intrusions larger than 350 mm, the inboard deflections (caused by interaction to the far-side occupant) were of the same magnitude or even higher (30–70 mm) than the outboard deflections (30–50 mm).Conclusion: A WorldSID 50th percentile male equipped with bilateral IR-Traccs can detect loading to the thorax from a neighboring occupant making injury risk assessment feasible for this type of loading. At crash severities resulting in a delta V above 35 km/h and intrusions larger than 350 mm, both the inboard deflection and VC resulted in high risks of Abbreviated Injury Scale (AIS) 3+ injury, especially for a senior occupant.

Study of injury mechanism of far-side occupant in K-car side collision

Study of injury mechanism of far-side occupant in K-car side collision

Factors That Influence Chest Injuries in Rollovers

Objectives: The design of countermeasures to reduce serious chest injuries for belted occupants involved in rollover crashes requires an understanding of the cause of these injuries and of the test conditions to assure the effectiveness of the countermeasures. This study defines rollover environments and occupant-to-vehicle interactions that cause chest injuries for belted drivers.Methods: The NASS-CDS was examined to determine the frequency and crash severity for belted drivers with serious (Abbreviated Injury Scale [AIS] 3+) chest injuries in rollovers. Case studies of NASS crashes with serious chest injuries sustained by belted front occupants were undertaken and damage patterns were determined. Vehicle rollover tests with dummies were examined to determine occupant motion in crashes with damage similar to that observed in the NASS cases. Computer simulations were performed to further explore factors that could contribute to chest injury. Finite element model (FEM) vehicle models with both the FEM Hybrid III dummy and THUMS human model were used in the simulations.Results: Simulation of rollovers with 6 quarter-turns or less indicated that increases in the vehicle pitch, either positive or negative, increased the severity of dummy chest loadings. This finding was consistent with vehicle damage observations from NASS cases. For the far-side occupant, the maximum chest loadings were caused by belt and side interactions during the third quarter-turn and by the center console loading during the fourth quarter-turn. The results showed that the THUMS dummy produced more realistic kinematics and improved insights into skeletal and chest organ loadings compared to the Hybrid III dummy.Conclusions: These results suggest that a dynamic rollover test to encourage chest injury reduction countermeasures should induce a roll of at least 4 quarter-turns and should also include initial vehicle pitch and/or yaw so that the vehicle's axis of rotation is not aligned with its inertial roll axis during the initial stage of the rollover.

Influence of a Combo Side Airbag on the Risk for Basilar Skull Fracture in a Far-Side Occupant

Objective: The impact force to the head and neck were measured in sled tests with and without inflation of a combo airbag for a far-side occupant to determine the risk for basilar skull fracture.Methods: Sled tests were run at 24 and 32 km/h (15 and 20 mph) with and without inflation of a combo side airbag to analyze the effect of cross-car diving into the side interior. The matched tests involved one pair at 24 km/h and another at 32 km/h. The 24 km/h pair involved a lap–shoulder-belted 5th percentile female Hybrid III and the series at 32 km/h involved an unbelted 5th percentile Hybrid III. The dummy was ballasted to 69.5 kg (153 lb) and laid on the right side. The dummy was positioned 30.5 cm (12″) from the far-side interior to ensure the full sled delta V occurred before head impact. The buck consisted of a 2001 Ford Taurus. The combo thorax–head side airbag was stored in the seatback. The airbag was triggered about 120 ms before the head impact. The head, chest, and pelvis were instrumented with triaxial accelerometers and the upper and lower neck, thoracic spine, and lumbar spine had transducers measuring triaxial loads and moments. High-speed video recorded different views of the dummy motion. Dummy kinematics and biomechanical responses were compared to study the influence of inflating the side airbag on the head and neck.Results: The top of the head impacted the far side. The force of impact was similar with and without the airbag as the head compressed the airbag and loaded the vehicle interior trim behind the airbag. The peak force on the head was primarily from neck load as torso augmentation occurred. For the 24 km/h (15 mph) tests, the peak force was 4.7 kN (1055 lb) without and 4.8 kN (1088 lb) with the airbag and there was over 2.67 kN (600 lb) of lap belt load. The peak head acceleration was 93 g without and 72 g with the airbag. For the 32 km/h (20 mph) tests, the force on the head was 15.3 kN (3433 lb) without and 15.2 kN (3406 lb) with the airbag, although the instrumentation saturated. The peak head acceleration was 236 g without and 262 g with the airbag.Conclusion: The airbag reduced head acceleration in the belted test but did not influence the diving forces from torso augmentation through the neck of the far-side occupant. The side airbag did not reduce the risk for basilar skull fracture due to high neck compression loads in either the belted or unbelted tests.

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

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

Severe Injury to Near- and Far-Seated Occupants in Side Impacts by Crash Severity and Belt Use

Purpose: This study investigated the risk of severe-to-fatal injury (MAIS 4+F) to near- and far-seated front occupants in side impacts by belt use and crash severity (delta V). Methods: 1993–2007 NASS-CDS was analyzed for front-seat occupants in side impacts while they were either the near-side or far-side occupant by belt use. Light vehicles were included with model year 1994+. Injury severity was subdivided into MAIS 0–2, 3, and 4+F. The risk for MAIS 4+F injury was determined by dividing the number of MAIS 4+F by the number of exposed occupants with known injuries. Individual NASS-CDS cases were downloaded from the 1997–2007 electronic data to evaluate injury patterns causing high relative risks. Results: In 35+ mph side-impact delta Vs, the risk for MAIS 4+F injury was 75.4 ± 41.0% for unbelted near-side and 48.1 ± 14.6% for unbelted far-side occupants. The risk was 51.8 ± 14.8% for belted near-side and 30.9 ± 8.2% for far-side occupants. Seat belt use was 81.4% effective in preventing MAIS 4+F injury for near-side occupants and 93.5% for far-side occupants. The relative risk (RR) for unbelted compared to belted occupants was 35.9 for far-side occupants in 10–15 mph delta V crashes. The relative risk was 35.1 for near-side occupants in < 10 mph delta V side impacts. The high relative risks were associated with complex, high-speed multi-collision crashes often with occupant impacts on the windshield, steering wheel, or other frontal components and ejection. Conclusions: Seat belt use was more effective in preventing severe injury (MAIS 4+F) to far-side occupants than near-side occupants in < 25 mph delta V impacts. High relative risk for unbelted occupants in low-speed side impacts was explained by the fact that the accidents were high-speed, multi-impact collisions. Severe injury was caused by ejection, impact with the side interior, or impact with the frontal components where airbags sometimes deployed.

Occupant injury severity from lateral collisions: A literature review

Problem Side impacts are a serious automotive injury problem; they represent about 30% of all fatalities for passenger vehicle occupants. This literature review focuses on occupant injuries resulting from real lateral collisions. It emphasizes the interaction between injury patterns and crash factors, taking into account type of injuries and their severity. It highlights what is known on the subject and suggests further studies. Method We reviewed papers identified by searches in two electronic databases for the 1996-2009 publication period, and in specific journals and conference proceedings. Results Studies on the Primary Direction of Force (PDOF) have revealed that fatal crashes occur most frequently when the PDOF is at 3 or 9 o'clock. The risk of serious injury is two to three times higher for the near-side occupant than for the far-side occupant. Head injuries predominate in oblique impacts and thoracic injuries in perpendicular ones. A few results are also reported on side airbag protection. Conclusions This literature review presents an overall picture of the injuries caused by lateral collisions, though each of the papers or articles examined focuses mostly on some particular aspect of the problem. The incidence of specific injuries depends on the data source used. Very few population-based analyses of lateral collision injuries were found. Impact on industry New studies are needed to evaluate new protective devices (e.g., lateral airbags, inflatable curtains). Without interfering with their care duties, Emergency Medical Technicians could be systematically trained to observe the collision's specific characteristics and to report all their relevant observations to the emergency physicians to increase the likelihood of prompt diagnosis and proper care.

Development of an occupant model for far-side vehicle crashes

The biofidelity and performance requirements for a far-side occupant model are described. Previous work is analysed that highlights the potential use of a modified version of the TNO Human Facet Model for simulating far-side impacts. The model's biofidelity and performance are compared with PMHS results from pelvic offset sled tests, pendulum tests and a full-scale far-side crash test. Results indicate that the model exhibits good biofidelity compared with PMHS results, specifically its ability to simulate: belt interaction with the shoulder; loading to the pelvis, thorax and abdomen and whole body kinematics in a full-vehicle far-side crash. The model's main limitations are that its thorax is less capable of matching the magnitude of deflection observed in the PMHS pendulum tests.

Far-Side Occupant Kinematics in Low Speed Lateral Sled

Objective. The objective of this study was to evaluate the far-side occupant kinematics in low-speed lateral pulses with and without a seatbelt system. Methods. The kinematics responses of three volunteers and a Hybrid III were compared in three low-to-moderate lateral pulses. The parameters evaluated were pulses and belt usage. A total of 24 tests were carried out in a side-impact sled. The subjects consisted of two 50th-percentile males (Vol 1 & 2), one 5th-percentile female (Vol 3), and a Hybrid III 50th-percentile male (ATD). All subjects were seated in a far-side impact. Three low speed pulses were used: Pulse 1: a 4 g at 6 km/h, Pulse 2: 4 g/8 kph followed by a -2.5 g pulse to simulate a low curb impact, and Pulse 3: a 4 g's pulse at 10 km/h. In addition, the kinematics result from Pulse 2 was used to assess the performance of a human model. The human model was developed by TNO. Results. For all three pulses, the peak head lateral displacement was greater with the 5th female (Vol 3) than the male volunteers. The ATD results in the 6 and 10 km/h pulses were comparable to the volunteers. However, in Pulse 2, the ATD motion was higher than the volunteers. Conclusion. The results obtained in this study suggest the Hybrid III is a somewhat conservative device for an evaluation of occupant kinematics in low-speed lateral pulses. The human model also seemed to be representative of volunteer kinematics.

Side Impact Protection - Occupants in the Far-Side Seat

Much of the applied vehicle side impact occupant protection research to date has concentrated on occupants seated beside the struck side of vehicles. These occupants are defined as ‘near-side occupants’. Regulatory side impact test standards focus exclusively on this scenario. Real world crash evidence however has shown that occupants seated on the side away from the struck side, defined as ‘far-side occupants’, are still subject to a risk of injury. Relatively little research literature is available that addresses the protection of far-side occupants. Existing three-pint seat belt restraint systems were primarily designed for frontal impacts. Consequently, there is an inability for these systems to perform as effectively under lateral loading, compared to longitudinal loading. This is particularly the case for far-side occupant restraints, where the occupant's upper tom has often been observed to slip out from under the sash part of the seat belt system. This paper examines side impact epidemiology from an injury causation perspective, and endeavours to explain evidence indicating head injuries and seat belt related injuries constitute a significant proportion of all far-side impact injuries. Injury mechanisms and key dynamic parameters governing injury severity are detailed. Computer models simulating the dynamic motion of vehicle far-side occupants are described. Occupant kinematics and injury parameters from the models are then compared with real world crash case studies. The paper finally suggests vehicle design strategies which are likely to reduce far-side injuries. Some alternative restraint systems are proposed as potential countermeasures to reduce occupant injuries.