| 1. |
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| 2. |
- Baker, Gretchen, et al.
(författare)
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Kinematics and Shoulder Belt Engagement of Children on Belt-Positioning Boosters during Emergency Braking Events
- 2017
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151.
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Konferensbidrag (refereegranskat)abstract
- Emergency braking can influence children’s posture and seatbelt interaction. To better protect children in crashes preceded by emergency braking, this study a ims to quantify kinematics and seatbelt engagement during braking events . Eighteen rear‐seated children were exposed to braking events with 1 g deceleration in a passenger vehi cle, restrained by the seatbelt on a booster cushion and an integrated booster cushion. Vehicle acceleration and video data were analysed to m easure head displacement and shoulder belt position. On the booster cushion the belt was generally mid‐sho ulder and lower on the torso with a gap, while on the integrated booster cushion i t was closer to the neck and hi gher on the torso without a gap. Average forward head displacement was 160 mm on the booster cushion and 150 mm on the integrated booster cushion. Generally, the belt maintained the same position on the shoulde r throughout braking, with exceptions influenced by shifted initial positions or non‐standard motions. Braking e vents placed the head approximately 150‐190 mm forward from the initial position, influenced by booster, statu re, and initial seatbelt positioning. This reinforces the importance of maintaining mid‐shoulder or close to neck bel t positions and upright, centred postures prior to emergency braking, which may influence the likelihood of imp acting the vehicle interior and sustaining head injuries in a subsequent crash.
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| 3. |
- Baker, Gretchen, 1994, et al.
(författare)
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KINEMATICS AND SHOULDER BELT ENGAGEMENT OF CHILDREN ON BELT-POSITIONING BOOSTERS DURING EVASIVE STEERING MANEUVERS
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To increase the protection of child passengers in crashes preceded by evasive steering, understanding of how children interact with the seatbelt in such situations is essential. This study aims to quantify child kinematics and describe child-to-restraint interaction during evasive steering maneuvers. Methods: Eighteen child volunteers (aged 5-10) were seated on the rear seat of a passenger vehicle. A professional driver made repeatable sharp turns at 50 km/h. Children were restrained by the seatbelt on a booster cushion (BC) and on an integrated booster cushion (IBC). Kinematics of the nasion and upper sternum were analyzed with video tracking software and shoulder belt (SB) engagement and position were evaluated. Results: Children moved laterally inboard, and SB-to-body interaction was influenced by booster and stature. For shorter children, the SB was closer to the neck with more of the belt webbing in contact with the torso and a more curved belt paths on the IBC compared to the BC, where less of the SB was in contact with the torso and straight belt paths were observed throughout steering. Taller children generally had the SB initially mid-shoulder with more contact between the SB and torso, resulting in curved belt paths at initial and maximum displacement on both boosters. Children loaded the shoulder belt by axially rotating their torso into the SB more often on the IBC compared to BC. The SB generally stayed on the shoulder, with 89% of slip-off instances occurring for shorter children on the BC. Shorter children on the BC had the largest average inboard nasion displacement of 105 mm initially and 120 mm overall. Taller children on the BC had the lowest average inboard displacement of the nasion (85 mm initially, 100 mm overall). All children initially displaced on average between 65-75 mm inboard with their sternum and 90 mm overall. Conclusions: Initial SB position on the shoulder and torso differed with booster and stature, which influenced how children engaged with the seatbelt during steering. Children with less SB initially in contact with the torso moved laterally behind the belt, resulting in straighter SB paths and outboard motion of the SB on the shoulder (often ending far out or slipped-off). When more of the SB was initially in contact with the torso, children tended to engage the SB more, moving with the belt and causing the SB path to become more curved, resulting in less inboard head displacement and less outboard motion of the SB on the shoulder. Enhanced understanding of how evasive steering affects the kinematic response of children provides valuable data for protection of children in real world situations.
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| 4. |
- Baker, Gretchen, 1994, et al.
(författare)
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Kinematics and shoulder belt engagement of children on belt-positioning boosters during evasive steering maneuvers
- 2018
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 19:S1, s. S131-S138
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To increase the protection of child passengers in crashes preceded by evasive steering, understanding of how children interact with the seat belt in such situations is essential. This study aims to quantify child kinematics and describe child-to-restraint interaction during evasive steering maneuvers. Methods: Eighteen child volunteers (aged 5–10) were seated on the rear seat of a passenger vehicle. A professional driver made repeatable sharp turns at 50 km/h. Children were restrained by the seat belt on a booster cushion (BC) and on an integrated booster cushion (IBC). Kinematics of the nasion and upper sternum were analyzed with video tracking software and shoulder belt (SB) engagement and position were evaluated. Results: Children moved laterally inboard, and SB-to-body interaction was influenced by booster and stature. Shorter children displayed initial SB positions closer to the neck with less instances of gap between the SB and the lower torso, resulting in more curved belt paths on the IBC. On the BC, shorter children had less of the SB in contact with the torso and straight belt paths were observed throughout steering. Taller children generally had the SB initially mid-shoulder with less instances of gap, resulting in curved belt paths at initial and maximum displacements on both boosters. Children loaded the shoulder belt by axially rotating their torso into the SB more often on the IBC compared to BC. The SB generally stayed on the shoulder, with 89% of slip-off instances occurring for shorter children on the BC. Shorter children on the BC had the largest average inboard nasion displacement (120 mm). Taller children on the BC had the lowest average inboard displacement of the nasion (100 mm). All children initially displaced on average 90 mm inboard with their upper sternum. Conclusions: Initial SB position on the shoulder and torso differed with booster and stature, which influenced how children engaged with the seat belt during steering. Children with less SB initially in contact with the torso moved laterally behind the belt, resulting in straighter SB paths and outboard motion of the SB on the shoulder (often ending far out or slipped off). When more of the SB was initially in contact with the torso, children tended to engage the SB more, moving with the belt and causing the SB path to become more curved, resulting in less inboard head displacement and less outboard motion of the SB on the shoulder. Enhanced understanding of how evasive steering affects the kinematic response of children provides valuable data for protection of children in real-world situations.
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| 5. |
- Bohman, Katarina, 1970, et al.
(författare)
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Kinematics and shoulder belt position of child rear seat passengers during vehicle maneuvers
- 2011
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Ingår i: Annals of Advances in Automotive Medicine. - 1943-2461. ; 55, s. 15-26
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Tidskriftsartikel (refereegranskat)abstract
- Head impact to the seat back has been identified as one important injury causation scenario for seat belt restrained, head-injured children and previous research highlighted vehicle maneuvers prior to impact as possible contributing factors. The aim was to quantify kinematics of child occupants during swerving maneuvers focusing on the child’s lateral movement and seat belt position relative to the child’s shoulder. A study was conducted on a closed-circuit test track with 16 children aged 4-12, restrained in the rear seat of a modern passenger vehicle. A professional driving instructor drove at 50 km/h making sharp turns in a repeatable fashion, resulting in inboard motion of the children. The children were exposed to two turns in each of two restraint systems. Shorter children were on a booster or highback booster cushion. The taller children were seated on a booster cushion or with only a lap and shoulder seat belt. Four film cameras were fixed in the vehicle monitoring the child. Vehicle data were also collected. The seat belt slipped off the shoulder in 1 of 5 turns, varying by age and restraint type. Among shorter children, the belt slipped off in a majority of turns when seated on a booster cushion while the belt remained on the shoulder when seated on the highback booster cushion. Among taller children, the shoulder belt moved far laterally on the shoulder in half of the turns. This data provides valuable knowledge on possible pre-impact postures of children as a result of vehicle swerving maneuvers for a variety of restraint systems.
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| 6. |
- Brolin, Karin, 1974, et al.
(författare)
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Active Spine Modeling Representing a 6 Year-Old Child
- 2014
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Ingår i: 7th World Congress of Biomechanics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In a car crash, properly restrained forward facing children may sustain head injuries due to contact with the car interior. Emergency events such as braking and steering will influence the kinematics of the child, thereby affecting the child’s interaction with the restraint systems. Volunteer experiments (Stockman et al. 2013) have shown that children around six years of age, properly restrained on a booster cushion, may slip out of the shoulder belt during a 1g emergency event, while older children can maintain their posture better. A numerical human body model of the 6 year-old would be a valuable tool to study and improve the performance of restraint systems in the pre-crash phase. Compared to a crash, an emergency event typically has low g and long duration loading; hence, the muscle activity will influence the kinematics of the child. Therefore, the aim of this work is to develop an active 6 year-old human body model.The 6 year-old facet occupant multi body model in the MADYMO code (TASS, Rijswijk, the Netherlands) was selected. The spine is composed of rigid vertebral bodies connected with spherical joints. Muscle activity was implemented by applying torques at each vertebral joint for flexion-extension and lateral bending. The torque actuators were controlled by proportional, integrative and derivative controllers comparing the current joint angles to an initial posture reference value. The controller gains were based on adult data and scaled by 50% for a first version of the active child model. The resulting active 6 year-old model was used to simulate the volunteer experiments by Stockman et al. 2013. The model was seated on a booster cushion and loaded with the average experimental pulse. The first version of the active child model had a significantly improved biofidelity compared to the original facet model, with shape and magnitude of displacements similar to the volunteer data, see Figure.It is concluded that the first version active 6 year-old model can reproduce this specific emergency event. Future work should focus on controller gain optimization and further validation.
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| 7. |
- Brolin, Karin, 1974, et al.
(författare)
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Development of an Active 6-Year-Old Child Human Body Model for Simulation of Emergency Events
- 2015
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Ingår i: 2015 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; :IRC-15-74, s. 689-700
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Konferensbidrag (refereegranskat)abstract
- One contributing factor to head injury in restrained child occupants is pre‐crash maneuvers andactive child human body models (HBMs) can be useful tools to design pre‐crash interventions with child safety infocus. This paper implemented postural control in the MADYMO human facet occupant model of a 6‐year‐oldchild using feedback controlled torque actuators. Control parameters were tuned and the active HBM wascompared to experimental data from braking and steering events with child volunteers. The head and sternumdisplacements of the active HBM were within one standard deviation of the experimental data, while theoriginal HBM did not capture the volunteer kinematics at all. By predicting biofidelic child kinematics, thedeveloped model shows potential as a useful tool for the automotive industry to study the protective propertiesof restraint systems in pre‐crash scenarios. For autonomous steering events, it was illustrated that the shape ofthe acceleration pulse highly influences the peak head displacements of child occupants. This is an aspect thatneeds to be considered when autonomous interventions are designed, to ensure the safety of short forwardfacing child occupants.
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| 8. |
- Brolin, Karin, 1974, et al.
(författare)
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Safety of children in cars: A review of biomechanical aspects and human body models
- 2015
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Ingår i: IATSS Research. - : Elsevier BV. - 0386-1112. ; 38:2, s. 92-102
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Forskningsöversikt (refereegranskat)abstract
- The protection of children in motor vehicle crashes has improved since the introduction of child restraint systems. However, motor vehicle crashes remain one of the top leading causes of death for children. Today, computer-aided engineering is an essential part of vehicle development and it is anticipated that safety assessments will increasingly rely on simulations. Therefore, this study presents a review of important biomechanical aspects for the safety of children in cars, including child human body models, for scenarios ranging from on-road driving, emergency maneuvers, and pre-crash events to crash loading. The review is divided into four parts: Crash safety, On-road driving for forward facing children, Numerical whole body models, and Discussion and future outlook.The first two parts provide ample references and a state-of-the-art description of important biomechanical aspects for the safety of children in cars. That children are not small adults has been known for decades and has been considered during the development of current restraints that protect the child in the crash phase. The head, neck, thorax, and pelvis are body areas where development with age changes the biomechanics and the interaction with restraint systems. The rear facing child seat distributes the crash load over a large area of the body and has proved to be a very efficient means of reducing child injuries and fatalities. Children up to age 4. years need to be seated rearward facing for optimal protection, mainly because of the proportionally large head, neck anthropometry and cartilaginous pelvis. Children aged 4 up to 12. years should use a belt positioning booster together with the vehicle seat belt to ensure good protection, as the pelvis is not fully developed and because of the smaller size of these children compared to adults. On-road driving studies have illustrated that children frequently change seated posture and may choose slouched positions that are poor for lap belt interaction if seated directly on the rear seat. Emergency maneuvers with volunteers illustrate that pre-crash loading forces forward-facing children into involuntary postures with large head displacements, having potential influence on the risk of head impact. Children, similar to adults, benefit from the safety systems offered in the vehicle. By providing child adaptability of the vehicle, such as integrated booster cushions, the child-restraint interaction can be further optimized. An example of this is the significant reduction of lap belt misuse when using integrated boosters, due to the simplified and natural positioning of the lap belt in close contact with the pelvis. The research presented in this review illustrates that there is a need for enhanced tools, such as child human body models, to take into account the requirements of children of different ages and sizes in the development of countermeasures.To study how children interact with restraints during on-road driving and during pre- and in-crash events, numerical child models implementing age-specific anthropometric features will be essential. The review of human whole body models covers multi body models (age 1.5 to 15. years) and finite element models (ages 3, 6, and 10. years). All reviewed child models are developed for crash scenarios. The only finite element models to implement age dependent anthropometry details for the spine and pelvis were a 3. year-old model and an upcoming 10. year-old model. One ongoing project is implementing active muscles response in a 6. year-old multi body model to study pre-crash scenarios. These active models are suitable for the next important step in providing the automotive industry with adequate tools for development and assessment of future restraint systems in the full sequence of events from pre- to in-crash.
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| 9. |
- Carlsson, Anna K, 1966, et al.
(författare)
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Barns Skallskador vid Olyckor i Personbil
- 2016
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Ingår i: Transportforum, January 12–13, 2016; Linköping, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Carlsson, Anna K, 1966, et al.
(författare)
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Review of Child Car Occupant Fatalities in Sweden During Six Decades
- 2013
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Ingår i: Proceedings: IRCOBI Conference; September 11-13; Gothenburg, Sweden. ; , s. 1-14
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Konferensbidrag (refereegranskat)abstract
- The development of fatal outcome was reviewed based on crash data including all fatally injured 0–14 year old car occupants in Sweden during 1956–2011 and put in relation to general improvements in vehicle and road safety and implementation of restraint systems.The review revealed a substantial decrease in crash‐related fatalities among 0–14 year old car occupants during the past three decades, representing a significant drop of 83% compared to the highest scores in the 1960s–70s. During 1992–2011, a total of 194 crash‐related fatalities were registered; the majority occurred on high‐speed roads. Head injury was a primary cause of death, in a total of 54% of all cases. Two fifths of the crashes involved a single car, while three fifths involved other vehicles. In total, 24% of the children were unrestrained, and 59% of those were ejected during crashes. Among the restrained children, 56% were considered to be appropriately restrained according to Swedish recommendations. Crash severity, complex crash situation, fire and drowning were factors that contributed to the fatal outcome, even though the restraint usage was considered to be optimal.
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