| 1. |
- Mroz, Krystoffer, 1966, et al.
(författare)
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Comparison of Hybrid III and human body models in evaluating thoracic response for various seat belt and airbag loading conditions
- 2010
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Ingår i: IRCOBI Conference. - 9783033025509 ; , s. 265-279
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Konferensbidrag (refereegranskat)abstract
- Thoracic responses between the Hybrid III model and the THUMS human body model were compared in three frontal impact severities for two belt (3-point and criss-cross), two belt load limiter (constant and degressive) and two airbag types (symmetric and non-symmetric). The thoracic responses were evaluated by measurements of chest deflections (mid-sternum and multi-point measured), chest excursions and, for the human body model, supplemented by maximum rib strains. For the 3-point belt, an overall correlation was found between Hybrid III and THUMS chest deflections and excursions as well as between THUMS multi-point chest deflections and rib strains. For the criss-cross belt, Hybrid III chest deflections increased and THUMS rib strains decreased. For the non-symmetric airbag, Hybrid III and THUMS chest deflections decreased.
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| 2. |
- Rizzi, Matteo, 1979, et al.
(författare)
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PROPOSED SPEED LIMITS FOR THE 2030 MOTOR VEHICLE
- 2023
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Ingår i: 27th ESV Conference Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Vision Zero builds on the aspiration to keep kinetic energy below human tolerance to prevent fatalities and serious injuries. In this work, a Swedish expert group within the SAFER arena estimated the maximum safe speed limits for the 2030 motor vehicle based on the boundary conditions of vehicles, road infrastructure and human crash tolerance to achieve close to zero road fatalities and serious injuries. The present work was based on expert consensus, rather than a retrospective quantitative analysis of crash data. Different load cases were discussed separately, with the involvement of a passenger car being the common denominator. The passenger car and its collision partner were assumed to be of model year 2030, thus reflecting the base safety level of the Swedish car fleet by approximately 2050. The boundary conditions were set based on pre-crash autonomous braking ability and the maximum acceptable impact speeds that would result in a very low risk of death or serious injury among the car occupants and the car’s collision partner. In the case of car to pedestrian impacts, the acceptable impact speed was set to zero, as any impact with pedestrians can lead to serious injuries as a result of ground impacts. It was expected that the responsibility to comply with speed limits will move from the driver to the car itself, and that travel speeds will be autonomously reduced when low road friction, sight obstructions, and other challenges in the traffic environment are detected. This function was expected to be non-overridable. Lateral control was also expected to be further enhanced with lane support technologies, although it was assumed that it will be still possible to override such technologies. Over time, increased performance of vehicle safety technologies will likely be able to prevent an increasingly large proportion of crashes in all load cases. However, in line with Vision Zero design principles, human crash tolerance will always be the ultimate boundary condition to guarantee a safe outcome in a crash. As a result, the recommended maximum travel speeds in the road transport system containing motor vehicles only of model year 2030 and beyond are: Rizzi 1 5-7 km/h in pedestrian priority areas, 40 km/h in mixed traffic urban areas, if there are no obstructed sensor sightlines, e.g. due to parked vehicles along the sidewalk, 50 to 80 km/h on roads without mid- and roadside barriers, 100+ km/h on roads with continuous mid- and roadside barriers, 40 to 60 km/h in intersections, depending on vehicle mass differences. The results from this work can be used to inform the development and amendment of transport planning guidelines when moving away from the economical paradigm into Safe System boundary conditions in the setting of speed limits.
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| 3. |
- 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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| 4. |
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| 5. |
- Boran, Colm, et al.
(författare)
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Saving Lives with V2X versus On-Board Sensing Systems -Which will be More Effective?
- 2012
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Tidskriftsartikel (refereegranskat)abstract
- Infrastructure systems such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2X) communication can theoretically prevent nearly all accidents by gathering the speed, locations, and travel directions of traffic participants, and intervening to control vehicle motion as required to help prevent collisions. However, during the phase-in of the communication systems, there will be many vehicles and many roads that do not have the communication systems in place, and therefore the system will not be effective in those cases. This lack of availability is likely the main disadvantage.On-board sensing (autonomous) systems such as cameras and radar sensors may not detect all potential hazards (e.g. due to weather, or hidden hazards), but they are effective in many situations and can help prevent crashes without depending on communication with infrastructure or other vehicles.This paper evaluates and compares the effectiveness of communication and on-board sensing technology in saving lives. Various implementation scenarios and system capabilities are investigated.
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| 6. |
- Boström, Ola, 1963, et al.
(författare)
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A new neck injury criterion candidate-based on injury findings in the cervical spinal ganglia after experimental neck extension trauma
- 1996
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Ingår i: PROCEEDINGS OF THE 1996 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF IMPACT, SEPTEMBER 11-13, DUBLIN, IRELAND. ; , s. 123-136
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Konferensbidrag (refereegranskat)abstract
- In this study a mathematical model, based on Navier Stokes equations, was developed and validated against experimental data. This model predicts the pressure changes in the spinal canal as a function of the volume change inside the canal during neck bending in the x-z (sagittal) plane. Another aim of the study was to investigate pressure phenomena and ganglion injuries at static neck extension loading and dynamic neck extension trauma with a head-restraint present. Experiments on pigs were conducted. Preliminary results indicate that ganglion injuries, as well as pressure transients inside the spinal canal, seem to correlate to the phase shift when the neck passes an s-shape (or maximal retraction) during the rearward motion of the head. That is, when the upper neck quickly changes from a flexion to an extension shape. Static loading of the neck resulted in no signs of injuries to the ganglia. A possible candidate for a neck injury criterion is presented, based on the relative acceleration between the top and the bottom of the cervical spine. A tolerance level based on the pig tests is also discussed.
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| 7. |
- Boström, Ola, 1963
(författare)
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Classical Aspects on the Road to Quantum Gravity: A Study in the Framework of the New Variables
- 1994
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There has been a lot of progress in the quest for the structure of spacetime since a canonical non-perturbative quantization program for general relativity was set up ten years ago. The crucial ideas are two choices of coordinates on phase space. First, Hamiltonian gravity was reformulated in terms of an SL(2,C)-valued connection and a densitized triad, the Ashtekar variables. Then, loops came into the picture. The loop variables, a generalization of Wilson loops, were for the first time used in quantum gravity. This thesis tries to clarify and complement five papers by the author and collaborators concerning three topics in pure classical gravity. The first two, paper I and II, are studies of an earlier found generalization of possible actions for gravity. They prove in some sense that Einstein's cosmological constant is not unique. The moduli space of SL(2,C)-connections up to gauge transformations is in fact non- Hausdorff. The implications for the quantum theory are unknown, classically it implies a non-bijective transformation from Ashtekar to loop variables. Based on an analysis in the vacuum case, paper III and IV investigate the influence of a cosmological constant. The holonomy class is still an observable of the gravitational field but the intersection of the set of the degenerate points with the real slice of the constraint surface changes. The last paper, paper V, illuminates a new classical picture of quantum geometry. A Hamiltonian formulation of a distributional ansatz for the gravitational fields is here found, and the hope, just as for the analogous Regge calculus is to find a good working technique for solving practical problems in classical as well as quantum gravity.
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| 8. |
- 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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| 9. |
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| 10. |
- Boström, Ola, 1963, et al.
(författare)
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Prediction of neck injuries in rear impacts based on accident data and simulations
- 1997
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Ingår i: PROCEEDINGS OF THE 1997 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF IMPACT. ; , s. 251-264
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Konferensbidrag (refereegranskat)abstract
- Whiplash associated disorders, occurring in car accidents, are an increasing problem worldwide. According to real-life data from police records, the struck car's velocity change (delta V) and occupant gender are two of the most important factors related to Abbreviated Injury Scale (AIS) 1 neck injuries. In this study, a new rear-impact ranking of cars based on 4432 police reported accidents is presented. The ranking concerns the relative neck injury risk and compensates for the influences of car weight and gender. Moreover, some important factors influencing the risk of AIS 1 neck injury are proposed. These include: the stiffness, damping and yielding characteristics of the seat back, the muscle response of the occupant, and the delta V of the struck car and acceleration pulse. Using a mathematical model it is shown that the influence from these factors can be explained by a recently proposed neck injury criterion (NIC). This criterion is based on the neck motion at the passage of full neck retraction. The NIC, based on a number of volunteer tests, is analysed and validated. The consequence of injury outcome of an observed overall seat back stiffening is also discussed. In conclusion, for delta V below 20 km/h, real-life data show that the geometry of the head restraint is of minor importance. A seat back with low yielding limit or soft performance may be preferable. Moreover, the new NIC seems to be a good predictor of real-life neck injuries.
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