| 1. |
- Akselsson, Roland, et al.
(författare)
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Fysikaliska faktorer
- 1994
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Ingår i: Arbete Människa Teknik. - 9175224143 ; , s. 45-113
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Akselsson, Roland, et al.
(författare)
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Fysikaliska faktorer
- 2005
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Ingår i: Arbete Människa Teknik. - 9175228955 ; , s. 45-113
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
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| 4. |
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| 5. |
- Andersson, Marianne, 1969, et al.
(författare)
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Characteristics of crashes involving injured children in side impacts
- 2011
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Ingår i: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 16:4, s. 365-373
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to define the crash characteristics of near-side impact crashes in which children seated in the rear rows are injured. The crash characteristics included the direction of force, heading angle, horizontal impact location, vertical impact location, extent of deformation and intrusion at the child occupant's seating position. Cases from in-depth crash investigation databases of the NASS-CDS (National Automotive Sampling System-Crashworthiness Data System), CIREN (Crash Injury Research and Engineering Network) and Chalmers University of Technology were reviewed. The principal direction of force was most frequently between 60° and 75°. The heading angle of the bullet vehicle was most commonly between 61° and 90°. The bullet vehicle hit the passenger compartment of the target vehicle, particularly the rear door. Often, one or both of the adjacent pillars to the rear door were involved, most commonly the B pillar. In 11 of 16 crashes, the car sill was not engaged. Most commonly, the deformation extent was into Zone 3 or more – about 40 cm – and the intrusion at the child's seating position was in the range 20–30 cm. This review of the crashes revealed differences between the current side impact test procedures and the actual side impact crashes in which children were injured.
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| 6. |
- Andersson, Marianne, 1969, et al.
(författare)
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Evaluation of the Head Kinematics of the Q3 Model and a Modified Q3 Model by Means of Crash Reconstruction
- 2012
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 13:6, s. 600-611
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Tidskriftsartikel (refereegranskat)abstract
- Objective: One objective of this study is to evaluate the head kinematics of the Q3 model. Another objective is to evaluate the effect on head kinematics of increased thoracic spine flexibility; more humanlike mass distribution; and more humanlike body geometry in the Q3 model. The evaluations were based on the head kinematics of children deduced from real crashes and on new data of mass distribution and updated body dimensions for 3-year-olds. Methods: The head kinematics of the Q3 model was evaluated by comparing the Q3 model's head displacement response with the deduced response of 3-year-old children in real crashes. To do so, data from crashes were collected. The data were used to develop the mathematical vehicle and restraint system models (MADYMO, TASS, the Netherlands). Three crashes involving 3-year-old children in frontal impacts were reconstructed. The models were run 35 times each (one model per crash), each time with a different setting to each of the variables for which the exact value was not known. Examples of those variables include crash pulse, initial dummy position, and initial seat belt position. Two versions of the Q3 model were used: one that correlated with the Q3 ATD and one that was modified regarding anthropometry and thoracic flexibility. The basis for the updated anthropometry was new data regarding characteristic dimensions and mass distribution collected at a Swedish hospital. Results: In the anthropometry study, 26 children were measured. The main differences between the average of the measured children and the Q3 model were found in the mass distribution of the torso and thighs: the Q3's pelvis was too heavy and the thorax, abdomen/lumbar spine, and thighs were too light. Another difference was identified in the buttock-knee length. Two of the 3 reconstructed crashes had confirmed head impacts. The Q3 model responded with head kinematics that reflected the deduced courses of events for the real children in one of 3 crashes (the one without head impact). The modified Q3 model reflected the real children in 2 of 3 crashes. Conclusions: In high-severity, straight frontal crashes, the Q3 model predicted non-head impact adequately. However, in oblique frontal crashes, the Q3 model did not sufficiently predict the head impacts. The modified Q3 model predicted the head impacts better than the Q3 model did. Greater flexibility of the thorax and redistributed mass made a positive difference regarding the head kinematics.
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| 7. |
- Andersson, Marianne, 1969, et al.
(författare)
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Parameter study for child injury mitigation in near side impacts through FE simulations
- 2012
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 13:2, s. 182-192
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of this study is to investigate the effects by crash related car parameters on head and chest injury measures for 3- and 12-year-old children in near side impacts.Methods: The evaluation was made by using a model of a complete passenger car which was impacted laterally by a barrier. The car model was validated in two crash conditions: the IIHS and the USNCAP side impact tests. The SID-IIs and the HBM3 (THUMS 3-yo) finite element models were used for the parametric investigation (HBM3 on a booster). The car parameters were: vehicle mass, side impact structure stiffness, a head airbag, a thorax-pelvis airbag, and a seat belt with pretensioner. The studied dependent variables were: resultant head linear acceleration, resultant head rotational acceleration, chest viscous criterion, rib deflection, and relative velocity at head impact. The chest measurements were only considered for the SID-IIs.Results: The head airbag had the greatest effect on the head measurements for both of the occupant models. On average, it reduced the peak head linear acceleration by 54 g for the HBM3 and 78 g for the SID-IIs. The seat belt had the second greatest effect on the head measurements; the peak head linear accelerations were reduced on average by 39 g (HBM3) and 44 g (SID-IIs). The high stiffness side structure increased the SID-IIs head acceleration, while it had marginal effect on the HBM3. The vehicle mass had marginal effect on SID-IIs head accelerations, while the lower vehicle mass caused 18 g higher head acceleration for HBM3 and the greatest rotational acceleration. The thorax-pelvis airbag, the vehicle mass and the seat belt pretensioner affected the chest measurements the most. The presence of a thorax-pelvis airbag, high vehicle mass and a seat belt pretensioner all reduced the chest VC and peak rib deflection in the SID-IIs.Conclusions: The head and thorax-pelvis airbags have the potential to reduce injury measurements for both the SID-IIs and the HBM3, provided that the airbag properties are designed to consider these occupant sizes also. The seat belt pretensioner is also effective, provided that the lateral translation of the torso is managed by other features. The importance of lateral movement management is greater the smaller the occupant is. Light vehicles require interior restraint systems of higher performance than heavy vehicles do to achieve the same level of injury measures for a given side structure.
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| 8. |
- Andersson, Marianne, 1969, et al.
(författare)
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Rear Seat Child Safety in Near-Side Impacts: A Modeling Study of Common Sitting Positions
- 2013
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 14:2, s. 198-208
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The purpose of this study was to evaluate and propose improvements to the injury mitigation systems, in near-side impacts, for 6 common sitting positions of young adolescents using a previously validated model. Methods: The evaluation was made by using a model of a complete passenger car, including head and thorax–pelvis air bags, which was impacted laterally by a barrier in 2 load cases. The SID-IIs finite element model was used for the evaluations and was seated in 6 different positions in the rear outboard seat: the nominal anthropomorphic test device (ATD) position, 1 inboard position, 3 outboard positions, and 1 braking (forward) position. These positions have previously been identified as common sitting positions in awake and asleep children. The studied dependent variables were head injury criterion (HIC) 36, resultant head linear acceleration, resultant head rotational acceleration, chest viscous criterion, and chest deflection. Results: The lowest head injury measures were seen in the braking positions and in the nominal ATD position, and the highest were seen in the inboard and outboard positions. The lowest chest injury measures were recorded in the inboard and nominal ATD positions, and the highest were recorded in the outboard and braking positions. The occupant in the outboard positions interfered with the air bags during their deployment. The occupant in inboard and braking positions tended to push the curtain air bag over the windowsill. Conclusions: Studies that investigate the injury mitigation effects in common sitting positions, beyond the nominal ATD position, are essential to highlight means to provide improved and robust safety for child occupants. This study was based on the SID-IIs 5th percentile female, which has very similar anthropometry to a 50th percentile 12-year-old. Therefore, the conclusions of this study are applicable to many 11-year-olds up to young adolescents, as well as to small females.The outboard and inboard positions of this study resulted in the highest head injury measures. Although all of the injury measures were only slightly higher than the nominal position, the trends suggest that, in near-side impacts, these positions should be discouraged. The extensively outboard positions resulted in unfavorable air bag positioning during deployment. The inboard position resulted in head strikes further forward of the nominal one; the curtain air bags need inflated cells at all locations of head strike.
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| 9. |
- 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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| 10. |
- 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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| 11. |
- 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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| 12. |
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| 13. |
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| 14. |
- Davidsson, Johan, 1967, et al.
(författare)
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BioRID - A New Biofidelic Rear Impact Dummy
- 1998
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Ingår i: Proceeding of the 1998 International IRCOBI Conference on the Biomechanics of Impact. ; , s. 377-390
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Konferensbidrag (refereegranskat)
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| 15. |
- Davidsson, Johan, 1967, et al.
(författare)
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BioRID P3 – Design and Performance Compared to Hybrid III and Volunteers in Rear Impacts at ΔV=7 km/h
- 1999
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Ingår i: Proceeding of the 43rd STAPP Car Crash Conference, San Diego, USA. ; :SAE paper no. 99SC16, s. 253-265
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Konferensbidrag (refereegranskat)abstract
- Several investigators have noted limitations of the most commonly used dummy in rear impact testing, the Hybrid III. A dummy for rear impact testing, the BioRID I, has previously been presented. It was a step towards an effective tool for seat performance testing, but it was concluded that its neck extension and T1 upward motion were too small and that its user-friendliness could be improved.A new BioRID prototype has been developed. It has new neck muscle substitutes with damping and elastic elements that are independent of each other and fitted inside the torso. The new neck muscle substitutes extend to T3 and thus also load the upper thoracic spine. The new dummy has a softer thoracic spine and a torso made of softer rubber than was used for the original dummy. The BioRID prototype's performance was compared to that of volunteers, the BioRID I and Hybrid III in rear impacts at V=7 km/h. The kinematics response of the new BioRID prototype appears to be more human-like than that of the BioRID I and Hybrid III. The dummy also provides repeatable test results and is more user-friendly than the BioRID I.
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| 16. |
- Davidsson, Johan, 1967, et al.
(författare)
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Human Volunteer Kinematics in Rear-End Sled Collisions
- 1998
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Ingår i: Proceeding of the 1998 International IRCOBI Conference on the Biomechanics of Impact. ; , s. 289-301
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Konferensbidrag (refereegranskat)abstract
- A number of current projects are developing new crash test dummies for rear-end impact testing. The validation of such a dummy design requires human response data from pertinent test situations. The objectives of this study are to quantify human head, neck, chest, pelvis and femur mechanical response in a well defined test seat. Another aim is to see how the response varies with seat design and sled speed change during low-speed rear-end collisions. This data is intended to be used in the validation of the crash test dummy (BioRID I) in rear-end impact situations, with a focus on low delta V (velocity change) collisions. Thirteen human subjects were exposed to 28 rear-end collision sled impacts with velocity changes close to 5 and 7 krn/h respectively. The results showed vertical motion of the subjects' H-point caused by ramping up along the seat, a forward rotat ion of the subjects' femur and maybe a contraction of the subjects' gluteus muscles. A vertical motion of the subjects' torso and head was also observed. This motion was caused by a combination of ramping up along the seat back and the straightening of the thoracic kyphosis. In the first 100 ms after impact, several subjects flexed their head relative T1. These new data have proven to be useful as validation data for new rear-end impact dummies.
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| 17. |
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| 18. |
- Hillemyr, Angela, 1965, et al.
(författare)
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Implementation of an organisational model to stimulate interaction between academia and industry
- 2015
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Ingår i: 2015 University-Industry Interaction Conference (UIIN) in Berlin, 24th - 26th June.
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Konferensbidrag (refereegranskat)abstract
- For most universities, especially in technical and medical disciplines, there has been a clear ambition to conduct applied research with a focus on utilisation. Research collaboration between industry and universities promotes improvement and innovation in industry and helps to ensure industrial relevance in academic research. In this paper an organisational model to strengthen interaction between academia and industry is presented along with the results so far. One of the aims of the model is to further stimulate utilisation within the Department of Applied Mechanics at Chalmers University of Technology, which is also in line with one of the University's four main objectives. The various components in the model were developed during a series of workshops run over a period of six months. One of the focal points of these workshops was to define Key Performance Indicators (KPIs) common to the Department. In the initial task of registering the KPIs, it became obvious that not all of them were appli-cable within every research division at the Department because of the differences in the work being pursued in research and education. The KPIs vary in relevance and have been modified several times. Today the KPIs are stable and for some of them trends have been identified. By deploying the organisational model we are now able to track, measure and display our utilisation efforts to improve them further and to create new incentives. Overall, the model has made a valuable contribution to everyday life at the Department and its partners. The mindset of the researchers has slowly changed in favour of utilisation as a key area, putting it on a par with research and education. However, one problem that still exists is to objectively measure and be credited for utilisation in conjunction with promotion to higher academic positions.Experience to date shows that the organisational model is a candidate model for university-wide implementa-tion. This will lead to more initiatives for, and greater attention to, utilisation and impact in proposals and in the dialogue with industry.
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| 19. |
- Hillemyr, Angela, 1965, et al.
(författare)
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Management-Driven University-Industry Interaction for Successful Impact
- 2016
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Ingår i: UIIN Conference proceedings.
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Konferensbidrag (refereegranskat)abstract
- AbstractAn organisational model that allows operations to be directed has been developed and has been in use for a number of years. It has now been developed further to highlight a process that will permit the successful impact of university-industry interaction to be sustained. With the experience of agreed parameters, or KPIs, their interrelationship and what each parameter is driving can now be evaluated. The rationale behind the model can be divided into three parts:Monitor and follow up a number of parameters, including satisfaction, collaboration and strategies (KPIs)Promote greater understanding of a common vision and goals using workshops and oth-er meansEncourage research groups to work with a vision aimed at desired impacts and to visu-alise how far the group has come in the processThe long-term ambition is to develop a strategy and build up a vision regarding the impact academ-ics would like to see in the future based on their research and education. Close relations with indus-try and society are an essential part of the process in order to incorporate relevance into research and teaching activities and by doing so meet the expectations of industry and society. The key to the process is not just conventional deliverables, such as bibliometric data, but also the impact of the research, including issues related to attitudes, standards and rules set by society. A research group’s potential to work towards desired impacts requires the involvement of the whole group in the task of defining the aims and visions behind the research. To achieve this, our original organisational model has been developed to establish the strategy and goals and to stimulate internal communication even further. The underlying concept is to visualise how far the group has come in the process. This can be described in the following steps:InputActivitiesOutputOutcomeImpact The results of the improved organisational model show the strength of each KPI and how the KPIs are related to each other. The results are used as key input for the strategy employed within the or-ganisation and the research impact and goals are visualised in a transparent way. The preliminary results show that management-driven university-industry interaction and engagement with re-searchers will lead to improved knowledge transfer and ultimately greater impact.
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| 20. |
- Johansson, Marianne, 1969, et al.
(författare)
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Child Safety in Vehicles: Validation of a mathematical model and development of restraint system design guidelines for 3-year-olds through mathematical simulations
- 2009
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 10:5, s. 467-478
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objectives of this study are to validate a mathematical simulation model of the Q3 ATD in an integrated forward-facing booster-type restraint in the rear seat and to evaluate restraint parameters to further develop design guidelines for this type of restraint system for forward facing children corresponding to the size of the Q3. Only frontal impact was considered.Methods: The software MADYMO was used to create and run the model of the restraint system and model of the child. The restraint system consisted of a seat and a safety belt. The child dummy model was the Q3. The complete model was validated to sled tests on 12 response signals: displacements of the dummy model, safety belt forces, and dummy model accelerations. The method used in the evaluation of the restraint parameters was a factorial design of experiments (DOE). The study included a total of 9 parameters: 6 related to the safety belt, such as pretensioner, load limiter, and belt anchor positions; two parameters related to the seat (stiffness and pitch angle); and one related to the foot support. The parameters were evaluated based on their effect on a number of dummy model responses.Results: The validation study showed that the mathematical model predicted the ATD's kinematics and measurements. Furthermore, the parameters that had the greatest effect on the dummy model responses were the lap belt angle, the D-ring x and y positions (upper belt anchor), the retractor pretensioner, and the retractor load limiter. The lap belt angle had the greatest effects of all parameters. The resulting head x displacement was 7.8 cm shorter with a lap belt angle of 24 degrees to the horizontal, compared to a 73 degrees to the horizontal lap belt angle; it also resulted in a reduction of the head resultant acceleration by 9.8 g.Conclusions: In order to decrease the Q3 ATD head, chest and pelvis accelerations and to limit the Q3 ATD head displacement, the following practices are recommended: first, position the D-ring rearward of the ATD so that the belt encloses the ATD's shoulder; second, position the lap belt anchors to make the lap belt angle 24 degrees to the horizontal, but make sure submarining is not induced; and finally, use a safety belt with pretensioner and load limiter functions. However, these recommendations need to be balanced with the recommendations for other occupant sizes, and any specific settings have to be evaluated further before introduction into vehicles.
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| 21. |
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| 22. |
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| 23. |
- Linder, Astrid, et al.
(författare)
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Design and validation of the neck for a rear impact dummy (BioRID I)
- 2002
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-9588 .- 1538-957X. ; 3:2, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- To assess the protective performance of seats and head restraints, occupant models able to mimic the motion of a human in a crash are needed. Hence, a new mechanical dummy neck for low-velocity rear collision tests was developed. The dummy neck consists of seven cervical elements connected by pin joints. The stiffness properties of the neck were represented by rubber blocks mounted between each pair of vertebrae, as well as by muscle substitutes between the head and the first thoracic vertebra (T1). The muscle substitutes consist of cables connected to a unit containing springs and a damper. The neck was validated against volunteer test data (Δv of 7 km/h) and compared with the kinematics of the Hybrid III dummy. The new neck was tested as a part of a new dummy (BioRID) that produced a human-like motion of the T1. The kinematics of the new neck was within the corridor of the volunteers, during the major part of the first 250 ms of the crash event, for both displacement of the head relative to T1 and for the acceleration of the head. This applies to both duration and peak values. When compared with the new neck, the Hybrid III showed an earlier decrease of the horizontal acceleration of the head, less maximum horizontal displacement, and an earlier increase of the rearward angular displacement of the head relative to T1.
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| 24. |
- Linder, Astrid, et al.
(författare)
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The New Neck Design for the Rear-End Impact Dummy, BioRID I
- 1998
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Ingår i: Annual Proceedings. - : Association for the Advancement of Automotive Medicine. ; , s. 172-192
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A new mechanical neck was developed for a new dummy possessing a complete articulated spine, for low speed rear-end collisions. The new neck consists of seven cervical elements connected by hinge joints. The neck stiffness properties were created by rubber blocks between each pair of vertebrae in combination with simulated muscle elements between the head and T1. The neck was validated against volunteer tests (Δv of 7 km/h) results. Both displacement and acceleration of the head relative to the upper torso for both duration and peak values, were in agreement with the volunteer data.
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| 25. |
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| 26. |
- Liu, Xuejun, 1971, et al.
(författare)
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A study of influence of vehicle speed and front structure on pedestrian impact responses using mathematical models
- 2002
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Ingår i: Traffic Injury Prevention. - 1538-957X .- 1538-9588. ; 3:1, s. 31-42
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Tidskriftsartikel (refereegranskat)abstract
- A validated pedestrian multibody model was used to investigate the influences of impact speed andvehicle front structure on the pedestrian dynamic responses in vehicle collisions. To predict theinjury risks of pedestrians at different impact speeds, the injury-related parameters concerninghead, chest and lower extremity areas were calculated from mathematical simulations. Four vehicletypes including large and compact passenger cars, minivans and light trucks were simulatedaccording to their frequency of involvement in real world accidents. The influences of variousvehicle front shape and compliance parameters were analyzed.Based on the results from the parametric study, the possible benefits from speed control in urbanarea were assessed, and a feasible speed limit was proposed to reduce the risks of pedestrianinjuries. Moreover, the possible countermeasures on basis of vehicle front design to mitigate theinjury severity of the pedestrians were discussed.
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| 27. |
- Ljung Aust, Mikael, 1973, et al.
(författare)
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Accident investigations for active safety at CHALMERS - new demands require new methodologies
- 2007
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 45:10, s. 881-894
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Tidskriftsartikel (refereegranskat)abstract
- In order to develop efficient active safety systems, knowledge about what causes traffic accidents is required. One way to gather such knowledge is through traffic accident investigations. For the needs of active safety, most current accident investigation methodologies do not provide a sufficiently detailed or theoretically anchored analysis. Therefore, new studies need to be carried out using new theoretical frameworks and analysis methods. At CHALMERS, a new methodology called driving reliability and error analysis method has been developed and tried out during recent years. The methodology, as described and exemplified, shows good promise of meeting the needs of active safety accident investigation projects. Results from studies using the methodology also imply consequences for how benefit estimation of new active safety systems should be carried out.
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| 28. |
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| 29. |
- Lövsund, Per, 1948-
(författare)
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Biological effects of alternating magnetic fields with special reference to the visual system
- 1980
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of the present investigation were to contribute to more knowledge of the interaction between extremely low frequency magnetic fields and excitable tissue and to widen the basic understanding of the mechanisms behind these effects. The human visual system and the frog retina were used as model systems.In order to ensure that industrial magnetic flux densities and frequencies were employed in the laboratory studies, the magnetic field levels in the welding and electrosteelindustries at the site ordinarily occupied by the operator were first measured. These processes usually generated fields with a frequency of 50 Hz and a magnetic flux density of 01-10 mT. In the laboratory magnetic fields (0-40 mT, 10-50Hz) were used to induce visual light phenomena, so-called magnetophosphenes, in volunteers. The threshold values for these phosphcnes were detennined as functions of magnetic field frequency as well as of colour and intensity of the background illumination. Maximum field sensitivity occurred at a frequency of approximately 20-30 Hz. With broad spectrum light the threshold flux density was about 10-12 mT. The thresholds were found to be dependent upon the intensity and the spectral distribution of the background light. During dark-adaptation the magnetic field sensitivity decreased. In certain respects volunteers with normal colour vision differed from colour defective ones as far as threshold values are concerned. Possible mechanisms for generation of magnetophosphenes are discussed. The threshold values for magnetophosphenes (0-40 mT) and electrophosphenes (0-0.3 mA) were compared under otherwise identical experimental conditions. In both broad spectrum and monochromatic background lighting the two types of phosphenes had a concurring sensitivity maximum at 20Hz. At higher frequencies there were significant differences in the threshold values. Applying electric current stimulation in different directions did not give rise to any great differences with regard to threshold values within the frequency range 10-30Hz. Frog retinas were exposed to magnetic fields (0-80 mT, 20-30 Hz). The electrical activity in the retina induced by the fields was registered from the ganglion cell layer with the aid of microelectrode technique, whereby a threshold value was obtained at approximately 20 mT and a sensitivity maximum was found at 20 Hz. The magnetic field response occurred within approximately 5 ms, while the light stimulus response occurred only after an average of approximately 85 ms. The latency from light stimulus to response in the ganglion cell layer was significantly prolonged if the preparation was simultaneously and continuously exposed to a magnetic field. Magnetic stimuli similar to light stimuli only induced a response upon 'on', 'off or 'on/off and not during continuous stimulation. Cells which were on-cells during light stimulation became off-cells during magnetic stimulation and vice versa. Addition of Na-aspartate or CoCl2 extinguished simultaneously the response both to light and to magnetic field stimuli. The results indicate that magnetophosphenes are generated in the retina and in the same channels that normally propagate signals induced by light.
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| 30. |
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| 31. |
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| 32. |
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| 33. |
- Lövsund, Per, 1948, et al.
(författare)
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Enhance interaction between HEIs and SMEs to stimulate research and innovation
- 2020
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Ingår i: 2020 University-Industry Interaction Online Conference.
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Konferensbidrag (refereegranskat)abstract
- To be more competitive and innovative, SMEs (Small and Medium-sized Enterprises) should benefit from access to more advanced research through an increased collaboration with HEIs (Higher Education Institutions). Based on the need to improve understanding of both the obstacles and opportunities regarding collaborations between SMEs and HEIs, the GIENAHS Erasmus Plus Project was established as a partnership between SMEs and HEIs from six EU countries. The study described in this paper aims to find ways for HEIs to improve their ability to interact with SMEs and vice versa, both through joint research and industry PhD students; as well as to propose strategies and methods for optimal long-term relationships and collaborations, including win-win situations for HEIs and SMEs. A questionnaire was developed and sent out to both HEIs and SMEs in each of the six partner countries. The results are based on the responses from 37 HEIs and 73 SMEs, which were analysed using the accepted model in decision theory, the Weighted Sum Model (WSM). The results were based mainly on the questionnaires, but also to some extent on complementary interviews. A great deal of the results are country specific, with some few exceptions. Besides the fact that the data differs between the countries, there is also a variation within the countries. There may be several reasons for these differences, for instance pre-existing SME/HEI relationships and collaborations, or if the university/department has a focus on applied or fundamental research. Both similarities and dissimilarities were found in the answers from both HEIs and SMEs. Both HEIs and SMEs share the viewpoint that they are open to collaborations for the purpose of a mutual transfer of knowledge. SMEs are generally interested in investing in staff competencies. The majority of the interviewed SMEs had not considered PhD programs before this study. The results show a willingness towards extending networks and contacts in order to create relationships and thus establish fruitful collaborations between HEIs and SMEs, thereby also enhancing research competence. This could potentially be done by establishing a common European standard for interaction between HEIs and SMEs. The conclusion of this study is in line with the project goal of increasing innovation capacity in the EU. It could broadly be summarised as: university-industry collaboration is a win-win experience for both parties as well as for society. It helps to close the gap between industry/SMEs and academia. A successful partnership involves strategies and goals for both HEIs and SMEs (industry) and for achieving impact.
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| 34. |
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| 35. |
- Lövsund, Per
(författare)
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Modeller inom det stötbiomekaniska området
- 1993
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Ingår i: VTI:s och TFB:s forskardagar. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 93-101
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 36. |
- Lövsund, Per, 1948, et al.
(författare)
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Passenger Car Crash Worthiness in Moose-Car Collisions
- 1989
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Ingår i: Proc Twelfth Int Techn Conf on Experimental Safety Vehicles (ESV). ; , s. 410-415
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Konferensbidrag (refereegranskat)abstract
- This paper describes the development and verification of a moose/dummy for testing the crash worthiness of cars in moose-car accidents.The dummy is based on and verified against the results of a staged collsion in which a passenger car impacts a moose cadaver. The cadaver test is also described in the report.Moose-car accidents contribute to about 2 percent of the death casualties in the Nordic road traffic and the type is even more represented among slighter injuries. Since several attempts to reduce the frequency of moose-car accidents have provided to have minor effect improvements of the crash worthiness of passenger cars in this kind of impact might be desirable.
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| 37. |
- Lövsund, Per, 1948
(författare)
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R&D related to Traffic Safety
- 2006
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Ingår i: Sino-Swedish Road and Vehicle Safety Seminars, Consulate General of Sweden and Swedish Trade Council, Shanghai, China 061031 and Embassy of Sweden and Swedish Trade Council, Beijing, China 061102.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 38. |
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| 39. |
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| 40. |
- Lövsund, Per
(författare)
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Vad vet vi om sidokollisioner?
- 1992
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Ingår i: VTI:s och TFB:s forskardagar. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 305-312
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 41. |
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| 42. |
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| 43. |
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| 44. |
- Sandin, Jesper, 1975-
(författare)
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Aggregating Case Studies of Vehicle Crashes by Means of Causation Charts : An Evaluation and Revision of the Driving Reliability and Error Analysis Method
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a need for increased knowledge about causes to motor-vehicle crashes and their prevention. Multidisciplinary in-depth case studies can provide detailed causation data that is otherwise unattainable. Such data might allow the formulation of hypotheses of causes and causal relationships for further study. By converting the data into causation charts that are aggregated, common causation patterns would give greater weight to such hypotheses. However the charts must first be compiled by means of a systematic analysis method, which requires three parts; a model, a classification scheme and a classification method.Four general accident models were evaluated and found inadequate to form the basis for a causation analysis method. This was primarily because the models in practice treat road-users, vehicles and traffic environment as separate components, but also due to the focus on events immediately prior to the crash and either static, sequential, or absent modelling of interaction.Two studies were carried out to evaluate whether case files could be aggregated by means of charts that had been compiled with the Driving Reliability and Error Analysis Method (DREAM). In DREAM, contributory factors (genotypes) are systematically analysed, classified and linked in a single chart for each driver that illustrate the causes of a critical event (phenotype). In the first study, case files from 38 single-vehicle crashes were examined to distinguish crashes with similar circumstances. Four types of loss of vehicle control were identified, for which the associated DREAM charts were aggregated. The results revealed common patterns within the types, as well as different patterns between them. The second study focused on 26 intersection crashes. Based on the most common violations at intersections, six risk situations were defined, and the DREAM charts associated with each risk situation were aggregated. A common pattern in each of two risk situations indicated that drivers with and without the right of way had not seen the other vehicle due to distractions and/or sight obstructions. A frequently occurring pattern for the drivers with the right of way was that they had not expected another vehicle to cross their path. The absence of clear patterns in three risk situations was a result of a low number of charts and rather unique circumstances in these cases. Parts of the aggregated charts contained an unexpectedly large variation, identified as a consequence of inconsistently compiled charts.Prior the final study assessing intercoder agreement, DREAM was revised into a new version based on the experience from the latter aggregation study. A total of seven investigators from four European countries compiled seven DREAM charts for each driver involved in four types of accidents. The results indicated that the intercoder agreement for genotypes ranged from 74% to 94% with an average of 83%, while it for phenotypes ranged from 57% to 100% with an average of 78%. This acceptable level of agreement is expected to rise with enhanced training. The present thesis thus shows that DREAM is a highly promising method for the compilation of causation charts. Future studies are expected to benefit from aggregating DREAM charts when formulating hypotheses of general causes and causal relationships as a subject for further research, as well as to identify alternative countermeasure strategies.
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| 45. |
- Svensson, Mats, 1960, et al.
(författare)
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A DUMMY FOR REAR-END COLLISIONS: DEVELOPMENT AND VALIDATION OF A NEW DUMMY NECK
- 1992
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Ingår i: PROCEEDINGS OF THE 1992 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF IMPACTS. ; , s. 299-310
-
Konferensbidrag (refereegranskat)abstract
- This study develops and validates a new dummy neck for rear-end collision testing. The effectiveness of passenger car head rests in rear-end collisions remaines poor and whiplash injuries, often occurring at low impact speeds, are a great problem. Until now, there has been no acceptable dummy for rear-end impact testing. The new neck consists of seven cervical and two thoracic vertebrae connected with pin joints. It is designed solely for rear-end collision testing at low impact speeds (lower than 20 km/h). It was validated using a series of volunteer tests. It showed good accordance. A Hybrid III neck was tested under the same conditions. This neck proved to be stiff. It also appeared to have too high resistance to horizontal translational motion between head and torso
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| 46. |
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| 47. |
- Svensson, Mats, 1960, et al.
(författare)
-
Neck injuries in car collisions--a review covering a possible injury mechanism and the development of a new rear-impact dummy
- 2000
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Ingår i: Accident Analysis and Prevention. - 0001-4575. ; 32:2, s. 167-75
-
Tidskriftsartikel (refereegranskat)abstract
- A review of a few Swedish research projects on soft tissue neck injuries in car collisions is presented together with some new results. Efforts to determine neck injury mechanisms was based on a hypothesis stating that injuries to the nerve root region in the cervical spine are a result of transient pressure gradients in the spinal canal during rapid neck bending. In experimental neck trauma research on animals, pressure gradients were observed and indications of nerve cell membrane dysfunction were found in the cervical spinal ganglia. The experiments covered neck extension, flexion and lateral bending. A theoretical model in which fluid flow was predicted to cause the transient pressure gradients was developed and a neck injury criterion based on Navier-Stokes Equations was applied on the flow model. The theory behind the Neck Injury Criterion indicates that the neck injury occurs early on in the rearward motion of the head relative to the torso in a rear-end collision. Thus the relative horizontal acceleration and velocity between the head and the torso should be restricted during the early head-neck motion to avoid neck injury. A Bio-fidelic Rear Impact Dummy (BioRID) was developed in several steps and validated against volunteer test results. The new dummy was partly based on the Hybrid III dummy. It had a new articulated spine with curvature and range of motion resembling that of a human being. A new crash dummy and a neck injury criterion will be very important components in a future rear-impact crash test procedure.
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| 48. |
- Svensson, Mats, 1960, et al.
(författare)
-
Nervenzellschäden bei Schleudertraumen. Tierexperimentelle Untersuchungen
- 1998
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Ingår i: Orthopäde. ; :27, s. 820-826
-
Tidskriftsartikel (refereegranskat)abstract
- Die mechanische Belastung der Halswirbelsäule (HWS) bei Autounfällen verursacht ofteine Reihe von Halsverletzungen, die unterdem Begriff Schleudertrauma zusammengefaût werden. Mehrere dieser Symptomekönnen möglicherweise durch Verletzungenim Bereich der Nervenwurzeln der HWS erklärt werden. Die Hypothese wurde aufgestellt,daû während der Extensions- und Flexionsbewegungendes Halses, aufgrund vonhämodynamischen Auswirkungen, ¾nderungendes inneren Volumens des Halswirbelkanalskurzzeitige Druckveränderungenim ZNS verursachen und daû dadurch Gewebeschäden durch die mechanische Belastungder Nervenwurzel entstehen. Um dieHypothese zu überprüfen, wurden anästhesierteSchweine einem experimentellenSchleudertrauma mit Extensions-, FlexionsundSeitneigungsbewegungen ausgesetzt.Die traumatische Belastung wurde unterhalbeiner Stufe gehalten, bei der eine Halswirbelfrakturstattfinden könnte. Während derBelastung wurde der Pulsdruck im Halswirbelkanalgemessen. In diesem Zusammenhangergaben sich Hinweise einer Dysfunktionder Zellmembran bei Nervenzellkörpernder Spinalganglien. Die ganglionären Verletzungenkönnen möglicherweise einige dermit Weichteilverletzungen des Halses nachAutounfällen einhergehenden Symptomeerklären. Um die Situation bei einem Auffahrunfallzu simulieren, wurde der Kopf desSchweines rückwärts vom Torso weggezogen.Dabei wurde festgestellt, daû die ganglionären Verletzungen zu einem sehr frühenZeitpunkt während der Halsbewegungenstattfinden und zwar in der Phase, in der dieBewegung von der Retraktion zur Extensionwechselt. Bei einer ähnlichen, jedoch statischenBelastung des Halses wurden keineganglionären Verletzungen bei den Schweinenfestgestellt. Dies ist ein Hinweis darauf,daû diese Verletzungen durch dynamischeFaktoren verursacht werden und bietet somitweitere Unterstützung für die Druckhypothese.Auf der Basis eines theoretischen Modellswurden Kriterien für Halsverletzungen(neck injury criterion = NIC) entwickelt. Esweist darauf hin, daû das Risiko von ganglionären Verletzungen am Punkt der maximalenHalsretraktion durch die unterschiedlichehorizontale Beschleunigung und Geschwindigkeitzwischen Kopf und oberemTorso bestimmt wird.
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| 49. |
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| 50. |
- Svensson, Mats, 1960, et al.
(författare)
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The Influence of Seat-Back and Head-Restraint Properties on the Head-Neck Motion During Rear-Impact
- 1993
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Ingår i: Proc. 1993 Int IRCOBI Conf., Eindhoven, Netherlands. ; , s. 395-406
-
Konferensbidrag (refereegranskat)abstract
- One type of production-car front-seat with ahead-restraint was tested in simulated low-velocityrear-impacts using a Hybrid III-dummy fitted with amodified neck (RID-neck). The seat was modified invarious ways to test the influence of different seatproperties on the head-neck motion during theimpact.The results show that it is possible to influencethe head-neck kinematics to a great extent bymodifying the properties of the seat-back and thehead-restraint. It was possible to virtually eliminatethe neck extension motion during the rear-impactand this will hopefully result in a significantdecrease of the neck injury risk in real world rearimpacts.
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