| 1. |
- Boström, Ola, 1963, et al.
(författare)
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Comparison of car seats in low speed rear-end impacts using the BioRID dummy and the new neck injury criterion (NIC).
- 2000
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Ingår i: Accident Analysis and Prevention. ; 32:2, s. 321-328
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Tidskriftsartikel (refereegranskat)abstract
- Long-term whiplash associated disorders (WAD) 1-3 sustained in low velocity rear-end impacts is the most common disability injury in Sweden. Therefore, to determine neck injury mechanisms and develop methods to measure neck-injury related parameters are of importance for current crash-safety research. A new neck injury criterion (NIC) has previously been proposed and evaluated by means of dummy, human and mathematical rear-impact simulations. So far, the criterion appears to be sensitive to the major car and collision related risk factors for injuries with long-term consequences. To further evaluate the applicability of NIC, four seats were tested according to a recently proposed sled-test procedure. 'Good' as well as 'bad' seats were chosen on the basis of a recently presented disability risk ranking list. The dummy used in the current tests was the Biofidelic Rear Impact Dummy (BioRID). The results of this study showed that NICmax values were generally related to the real-world risk of long-term WAD 1-3. Furthermore, these results suggested that NICmax calculated from sled tests using the BioRID dummy can be used for evaluating the neck injury risk of different car seats.
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| 2. |
- Ghaffari, Ghazaleh, 1985, et al.
(författare)
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Passenger muscle responses in lane change and lane change with braking maneuvers using two belt configurations: Standard and reversible pre-pretensioner
- 2019
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 20:sup1, s. S43-S51
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Tidskriftsartikel (refereegranskat)abstract
- Objective : The introduction of integrated safety technologies in new car models calls for an improved understanding of the human occupant response in precrash situations. The aim of this article is to extensively study occupant muscle activation in vehicle maneuvers potentially occurring in precrash situations with different seat belt configurations. Methods : Front seat male passengers wearing a 3-point seat belt with either standard or pre-pretensioning functionality were exposed to multiple autonomously carried out lane change and lane change with braking maneuvers while traveling at 73 km/h. This article focuses on muscle activation data (surface electromyography [EMG] normalized using maximum voluntary contraction [MVC] data) obtained from 38 muscles in the neck, upper extremities, the torso, and lower extremities. The raw EMG data were filtered, rectified, and smoothed. All muscle activations were presented in corridors of mean ± one standard deviation. Separate Wilcoxon signed ranks tests were performed on volunteers’ muscle activation onset and amplitude considering 2 paired samples with the belt configuration as an independent factor. Results : In normal driving conditions prior to any of the evasive maneuvers, activity levels were low (<2% MVC) in all muscles except for the lumbar extensors (3–5.5% MVC). During the lane change maneuver, selective muscles were activated and these activations restricted the sideway motions due to inertial loading. Averaged muscle activity, predominantly in the neck, lumbar extensor, and abdominal muscles, increased up to 24% MVC soon after the vehicle accelerated in lateral direction for all volunteers. Differences in activation time and amplitude between muscles in the right and left sides of the body were observed relative to the vehicle’s lateral motion. For specific muscles, lane changes with the pre-pretensioner belt were associated with earlier muscle activation onsets and significantly smaller activation amplitudes than for the standard belt (P <.05). Conclusions : Applying a pre-pretensioner belt affected muscle activations; that is, amplitude and onset time. The present muscle activation data complement the results in a preceding publication, the volunteers’ kinematics and the boundary conditions from the same data set. An effect of belt configuration was also seen on previously published volunteers’ kinematics with lower lateral and forward displacements for head and upper torso using the pre-pretensioner belt versus the standard belt. The data provided in this article can be used for validation and further improvement of active human body models with active musculature in both sagittal and lateral loading scenarios intended for simulation of some evasive maneuvers that potentially occur prior to a crash.
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| 3. |
- Larsson, Emma, 1991, et al.
(författare)
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Active Human Body Model Predictions Compared to Volunteer Response in Experiments with Braking, Lane Change, and Combined Manoeuvres
- 2019
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; :S1-9, s. 349-369
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Konferensbidrag (refereegranskat)abstract
- Active human body models are an important tool to study occupant interaction with safety systems in evasive manoeuvres such as braking and/or steering. In this study a finite element human body model with and without closed-loop active muscle control in the neck and lower trunk was compared to volunteer occupants in six different load cases with lane change, braking, and combined manoeuvres using standard and prepretensioned seat belts. Seven different muscle controllers, using two different muscle activation strategies based either on head and torso displacements or muscle length, and one with the controller turned off have been compared to volunteer kinematics. Cross-correlation analysis with CORA was used to evaluate the model biofidelity. The results show an improvement in CORA scores when using active muscles, compared to the model with muscle activity turned off, for one load case and similar CORA scores between the models for five load cases. CORA scores ranged from 0.78 to 0.88 for the active models and 0.70 to 0.82 from the model with muscles turned off. The active model gave a kinematic response with good biofidelity in lane change with braking, pure braking, and lane change with pre-pretensioned seat belt, but the biofidelity of the model was rated as fair in lane change with standard seat belt.
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| 4. |
- Leledakis, Alexandros, 1991, et al.
(författare)
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A method for predicting crash configurations using counterfactual simulations and real-world data
- 2021
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 150
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Tidskriftsartikel (refereegranskat)abstract
- Traffic safety technologies revolve around two principle ideas; crash avoidance and injury mitigation for inevitable crashes. The development of relevant vehicle injury mitigating technologies should consider the interaction of those two technologies, ensuring that the inevitable crashes can be adequately managed by the occupant and vulnerable road user (VRU) protection systems. A step towards that is the accurate description of the expected crashes remaining when crash-avoiding technologies are available in vehicles. With the overall objective of facilitating the assessment of future traffic safety, this study develops a method for predicting crash configurations when introducing crash-avoiding countermeasures. The predicted crash configurations are one important factor for prioritizing the evaluation and development of future occupant and VRU protection systems. By using real-world traffic accident data to form the baseline and performing counterfactual model-in-the-loop (MIL) pre-crash simulations, the change in traffic situations (vehicle crashes) provided by vehicles with crash-avoiding technologies can be predicted. The method is built on a novel crash configuration definition, which supports further analysis of the in-crash phase. By clustering and grouping the remaining crashes, a limited number of crash configurations can be identified, still representing and covering the real-world variation. The developed method was applied using Swedish national- and in-depth accident data related to urban intersections and highway driving, and a conceptual Autonomous Emergency Braking system (AEB) computational model. Based on national crash data analysis, the conflict situations Same-Direction rear-end frontal (SD-ref) representing 53 % of highway vehicle-to-vehicle (v2v) crashes, and Straight Crossing Path (SCP) with 21 % of urban v2v intersection crashes were selected for this study. Pre-crash baselines, for SD-ref (n = 1010) and SCP (n = 4814), were prepared based on in-depth accident data and variations of these. Pre-crash simulations identified the crashes not avoided by the conceptual AEB, and the clustering of these revealed 5 and 52 representative crash configurations for the highway SD-ref and urban intersection SCP conflict situations, respectively, to be used in future crashworthiness studies. The results demonstrated a feasible way of identifying, in a predictive way, relevant crash configurations for in-crash testing of injury prevention capabilities.
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| 5. |
- Leledakis, Alexandros, 1991, et al.
(författare)
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Influence of an Individualised Shoulder Belt Position for Diverse Occupant Anthropometries on Seatbelt Interaction in Frontal and Side Impacts
- 2023
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; , s. 639-664
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Konferensbidrag (refereegranskat)abstract
- This simulation study investigated the influence of individualised shoulder belt position on seatbelt interaction and occupant kinematics in two frontal and one far side impact, considering the variability of occupant anthropometry and sitting postures. Morphed Human Body Models, positioned as front passengers, were simulated in 132 setups. For every occupant, an individualised shoulder belt position configuration was created by changing the D-ring mounting location, aiming for a mid-shoulder belt fit. A “traditional belt” configuration was also tested, with the D-ring mounted on the B-pillar. The initial belt's placement over the occupant's shoulder was influential; however, it may not necessarily lead to an overall improved seatbelt interaction as a single parameter. Different occupants were associated with different seatbelt interaction challenges. Tall occupants with low Body Mass Index (BMI) were more likely to slide out of the shoulder belt, while short low-BMI occupants were more likely to submarine. The early torso to pelvis retention balance and the torso’s axial rotations were identified as the main mechanisms behind those observations. The study identified seatbelt interaction challenges for different occupant groups and could facilitate the analysis of additional changes in belt characteristics towards individualised occupant restraint systems.
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| 6. |
- Leledakis, Alexandros, 1991, et al.
(författare)
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The influence of car passengers’ sitting postures in intersection crashes
- 2021
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Car passengers are frequently sitting in non-nominal postures and are able to perform a wide range of activities since they are not limited by tasks related to vehicle control, contrary to drivers. The anticipated introduction of Autonomous Driven vehicles could allow “drivers” to adopt similar postures and being involved in the same activities as passengers, allowing them a similar set of non-nominal postures. Therefore, the need to investigate the effects of non-nominal occupant sitting postures during relevant car crash events is becoming increasingly important. This study aims to investigate the effect of different postures of passengers in the front seat of a car on kinematic and kinetic responses during intersection crashes. A Human Body Model (HBM) was positioned in a numerical model of the front passenger seat of a midsize Sports Utility Vehicle (SUV) in a total of 35 postures, including variations to the lower and upper extremities, torso, and head postures. Three crash configurations, representative of predicted urban intersection crashes, were assessed in a simulation study; two side impacts, a near-side and a far-side, respectively, and a frontal impact. The occupant kinematics and internal loads were analyzed, and any deviation between the nominal and altered posture responses were quantified using cross-correlation of signals to highlight the most notable variations. Posture changes to the lower extremities had the largest overall influence on the lower extremities, pelvis, and whole-body responses for all crash configurations. In the frontal impact, crossing the legs allowed for the highest pelvis excursions and rotations, which affected the whole-body response the most. In the two side-impacts, leaning the torso in the coronal plane affected the torso and head kinematics by changing the interaction with the vehicle's interior. Additionally, in far-side impacts supporting the upper extremity on the center console resulted in increased torso excursions. Moreover, the response of the upper extremities was consistently sensitive to posture variations of all body regions.
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| 7. |
- Leledakis, Alexandros, 1991, et al.
(författare)
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The Influence of Occupant's Size, Shape and Seat Adjustment in Frontal and Side Impacts
- 2022
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; 2022-September, s. 549-584
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Konferensbidrag (refereegranskat)abstract
- The sensitivity of occupant kinematic and kinetic crash responses to anthropometric and seat adjustment variation was investigated by performing frontal- and side-impact simulations with a family of morphed Human Body Models (HBMs). The HBM family included variations of shape and size, accounting for stature, Body Mass Index (BMI) and sex. A global sensitivity analysis method was developed and applied. Increased BMI was associated with increased spinal and extremity loading in the HBM for all evaluated impacts. Increasing the stature resulted in a consistent increase in lower extremity loading. The fore-aft seat position influenced the head and torso speed relative to the vehicle interior. Furthermore, in high-severity frontal impacts, adjusting the seat position rearwards altered the load path, increasing the HBM pelvic and lumbar spine loading in favour of reducing the lower extremity forces, and vice versa when the seat was positioned forward. The results from this study highlight potential occupant protection challenges and trade-offs, and can be used to enhance protection, considering occupant anthropometric diversity and seat adjustment variation.
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| 8. |
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| 9. |
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| 10. |
- Mendoza-Vazquez, Manuel, 1979, et al.
(författare)
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Evaluation of Thoracic Injury Criteria for THUMS Finite Element Human Body Model Using Real-World Crash Data
- 2014
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Ingår i: IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, 10-12 September, Berlin, Germany. ; :IRC-14-62, s. 528-541
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Konferensbidrag (refereegranskat)abstract
- This study aims to compare the thoracic injury risk predicted by a modified THUMS with the risks predicted by an injury risk curve constructed based on real-world data. Since the injury risk curves for the modified THUMS were developed from reconstruction of post-mortem human subjects tests, it is of interest to investigate their performance in real-world crashes. For this purpose, an AIS2+ injury risk curve was constructed based on selected and representative frontal car crashes from the Volvo Cars' Traffic Statistical Accident Database. Six simulations with three different crash severities and two acceleration pulses for each severity were performed with THUMS in a detailed and representative interior vehicle model. The injury criteria Dmax, DcTHOR, shear stress and first principal strain in the ribs were computed with the modified THUMS and the risks were obtained from its previously developed injury risk curves. These risks were then compared to the risk from the real-world data. All four THUMS criteria predict higher risk compared to the risk predicted by the real-world injury risk curve. The risk estimated with Dmax was closest to the risk estimated by the injury risk curve based on real-world data.
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