| 1. |
- Holmqvist, Kristian, 1976, et al.
(författare)
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IMPROVING HYBRID III INJURY ASSESSMENT IN STEERING WHEEL RIM TO CHEST IMPACTS USING RESPONSES FROM FINITE ELEMENT HYBRID III AND HUMAN BODY MODEL
- 2014
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 15:2, s. 196-205
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The main aim of this study was to improve the quality of injury risk assessments in steering wheel rim to chest impacts when using the Hybrid III crash test dummy in frontal heavy goods vehicle (HGV) collision tests. Correction factors for chest injury criteria were calculated as the model chest injury parameter ratios between finite element (FE) Hybrid III, evaluated in relevant load cases, and the Total Human Model for Safety (THUMS). This is proposed to be used to compensate Hybrid III measurements in crash tests where steering wheel rim to chest impacts occur.Methods: The study was conducted in an FE environment using an FE-Hybrid III model and the THUMS. Two impactor shapes were used, a circular hub and a long, thin horizontal bar. Chest impacts at velocities ranging from 3.0 to 6.0m/s were simulated at 3 impact height levels. A ratio between FE-Hybrid III and THUMS chest injury parameters, maximum chest compression C-max, and maximum viscous criterion VCmax, were calculated for the different chest impact conditions to form a set of correction factors. The definition of the correction factor is based on the assumption that the response from a circular hub impact to the middle of the chest is well characterized and that injury risk measures are independent of impact height. The current limits for these chest injury criteria were used as a basis to develop correction factors that compensate for the limitations in biofidelity of the Hybrid III in steering wheel rim to chest impacts.Results: The hub and bar impactors produced considerably higher C-max and VCmax responses in the THUMS compared to the FE-Hybrid III. The correction factor for the responses of the FE-Hybrid III showed that the criteria responses for the bar impactor were consistently overestimated. Ratios based on Hybrid III and THUMS responses provided correction factors for the Hybrid III responses ranging from 0.84 to 0.93. These factors can be used to estimate C-max and VCmax values when the Hybrid III is used in crash tests for which steering wheel rim to chest interaction occurs.Conclusions: For the FE-Hybrid III, bar impacts caused higher chest deflection compared to hub impacts, although the contrary results were obtained with the more humanlike THUMS. Correction factors were developed that can be used to correct the Hybrid III chest responses. Higher injury criteria capping limits for steering wheel impacts are acceptable. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.
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| 2. |
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| 3. |
- Bálint, András, 1982, et al.
(författare)
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Correlation between truck combination length and injury risk
- 2013
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Ingår i: 2013 Australasian College of Road Safety Conference – “A Safe System: The Road Safety Discussion” Adelaide.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Literature studies show that it is a very complex task to estimate how traffic safety is affectedby the introduction of longer truck combinations. Some studies indicate a slightly increased risk of crashes per vehicle kilometre and that the change in risk depends on the vehiclecombination. Other studies show that the difference in crash risk in comparison to conventional heavy goods vehicles is small, at least for trucks travelling on larger roads. In the current study, the effect of increased vehicle combination length on the rates of fatal orsevere injury crashes by vehicle kilometres travelled is investigated. The method uses Swedish national crash data from the period 2003 to 2012. Unlike most other countries in the European Union where an upper limit of 18.75 metres is in force, vehicle combinations up to 25.25m are permitted in Sweden. The aim is therefore to determine whether “long” truck combinations (with a combination length of 18.76 – 25.25m) have a higher associated rate ofsevere or fatal crashes by vehicle kilometres travelled than “medium” (12.01 – 18.75m) or “short” combinations (less than 12m). Different approaches for comparing the number of fatal or severe crashes in the three lengthgroups with the kilometres driven are discussed. The crash type distributions in the three length groups are compared and it is considered to what extent the observed differences can be explained by differencesin the exposure data.
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| 4. |
- Fagerlind, Helen, 1975, et al.
(författare)
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Overview of Harmonized European Crash Investigations - From Focused Studies to a Holistic Approach
- 2013
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Ingår i: 2013 Road Safety and Simulation International Conference, RSS, Rome.
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Konferensbidrag (refereegranskat)abstract
- The aim with this paper is to describe the evolution of harmonized European crash investigations. The European Commission has during the past decade funded several specialized crash investigation studies focusing on: the cause of road crashes, child safety, crashes involving trucks and coaches; motorcycle crashes; rollover crashes; roadside infrastructure in run off road crashes; passive safety of passenger cars and fatal crashes. These projects included both methodology development and data collection and the databases comprises hundreds to a couple of thousand crashes each, from a nineteen countries in Europe. Due to the specific objective from study to study and the variation in the investigation methodology it is difficult to combine the existing data in a common analysis. To overcome these limitations and to enable aggregate analysis of in-depth data collected from different countries, a holistic crash investigation methodology was developed within the EU funded project DaCoTA. The holistic crash investigation methodology, further referred to as the Road Crash Information System (RCIS), has defined a common investigation procedure based on the previous studies. RCIS includes two useful tools. One is the on-line manual, publicly available on the internet, that in detail describes the procedures and the data variables collected. The other one is the web based open source application that, in a secure way, can be used to store, analyse and exchange data from different teams across Europe and further afield.
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| 5. |
- Holmqvist, Kristian, 1976, et al.
(författare)
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Challenges in Steering Wheel Rim to Thorax Impacts Using Finite Element Hybrid III and Human Body Models for Heavy Vehicle Frontal Crash Applications
- 2010
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Ingår i: International IRCOBI Conference on the Biomechanics of Impact. ; , s. 293-296
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Konferensbidrag (refereegranskat)abstract
- A risk of severe injuries from steering wheel rim to thorax contacts has been identified in heavy vehicle frontal collisions. The objective of this study was to investigate the effects in changing the steering wheel rim tilt angle on the thorax of the Hybrid III and a human body model THUMS with respect to chest deflection and steering wheel rim contact interaction. It was found that the Hybrid III chest is more sensitive to changes in steering wheel tilt angle than the THUMS.
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| 6. |
- Holmqvist, Kristian, 1976
(författare)
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Chest Injuries in Heavy Vehicle Frontal Collisions - Evaluation and Adaptation of the Hybrid III Dummy Instrumentation and Injury Reference Values by Means of Human Body Modeling
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The safety of passenger cars has been significantly improved during the last decades. Similar improvements are not as apparent in heavy vehicles and one of the reasons is believed to be deficiencies in heavy vehicle crash testing and the tools used to evaluate the biomechanical responses. The most commonly used dummy for frontal vehicular crash testing is the Hybrid III. This dummy was mainly intended for testing safety in passenger cars and is as such not appropriately evaluated for use in heavy vehicle driver environments. This research was initiated to evaluate the Hybrid III and its instrumentation for use in heavy vehicle frontal crash testing.The lack of appropriate biomechanical evaluation data lead to a new approach to Hybrid III chest performance evaluation. Finite element modeling was used as an alternative tool. Human body models and Hybrid III models were utilized and the results were compared. It became evident that the contact between the steering wheel rim and the driver’s chest was a critical load situation.A representative load case for heavy vehicle frontal collisions was identified. The occupant models were then evaluated using the best available validation setup. The THUMS proved to be the best available human body substitute in this context. The THUMS was thus used, coupled with the better of the two available Hybrid III models. A suitable Hybrid III chest deflection instrumentation has been identified and a transfer function between the Hybrid III chest response, during steering wheel rim contact, and established chest injury criteria were developed.
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| 7. |
- Holmqvist, Kristian, 1976, et al.
(författare)
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EVALUATION OF HYBRID III THORACIC INJURY CRITERIA IN IMPACTS WITH A SIMULATED TRUCK STEERING WHEEL – SUGGESTIONS FOR MODIFICATIONS IN INSTRUMENTATION AND REFERENCE VALUES
- 2009
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Ingår i: International IRCOBI Conference on the Biomechanics of Impact. ; , s. 201-204
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Konferensbidrag (refereegranskat)abstract
- Unbelted drivers of heavy commercial vehicles are likely to suffer chest injuries from steering wheel rim contact in frontal impacts. The aim of the present study was to investigate to what extent the current regulatory dummy, the Hybrid III, is capable of assessing the chest deflection in this load case. A Finite Element model of the dummy and its default sensors were evaluated together with chest injury criteria. The THUMS was used as a reference representing the human body. Suggestions on instrumentation and correction factors for injury criteria are proposed for use with the Hybrid III.
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| 8. |
- Holmqvist, Kristian, 1976
(författare)
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Heavy Vehicle Crash Safety - Improved Thoracic Injury Prediction in Frontal Crash Testing
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Frontal crashes are regarded as some of the most injurious accidents for Heavy Goods Vehicle (HGV) drivers. One of the leading HGV manufacturers regularly conducts frontal crash testing for occupant safety. The Hybrid III crash test dummy was developed for frontal testing in passenger cars and has become the standard in crash laboratories. This project was initiated to investigate the suitability of the Hybrid III in HGV frontal crash testing. The cab geometries and occupant posture in an HGV differ from passenger cars. The driver chest will thus experience a different loading in a frontal crash. The objective of this thesis was to establish if and how the Hybrid III could be used in frontal HGV crash tests, in particular how to best assess chest injury risk in HGV crash tests with the Hybrid III.Database analyses of real-world HGV crashes were carried out to establish which injuries to prioritise in the most common and serious crash types. The results confirmed that chest injuries in frontal crashes are a top priority. The chest was the body region with the highest frequency of severe injuries.The occupant load case was studied in frontal sled crash tests, with a Hybrid III seated in an HGV cab. The chest of the Hybrid III was found to contact the steering wheel rim in all tested configurations. The study concluded that the Hybrid III was able to accurately register chest deflections with the aid of additional instrumentation. Furthermore, the steering wheel rim-to-chest contact was found to be a previously unexplored load case in injury biomechanics, and the need for further biomechanical knowledge regarding this load case became apparent. A representative HGV frontal crash chest load case was identified. Post Mortem Human Subject (PMHS) testing provided data to confirm the suitability of the Finite Element (FE) Human Body Model (HMB) Total HUman Body Model for Safety (THUMS) as a human surrogate. An FE model of the Hybrid III was validated from physical tests in the representative load case. A simulation test matrix including the THUMS and the FE Hybrid III, was applied to develop a transfer function from the chest response of the Hybrid III to existing injury criteria. The application of the added chest deflection instrumentation and this transfer function enables much improved chest injury assessment with the Hybrid III in frontal HGV crash tests. These results have the potential to facilitate the development of improved HGV occupant safety systems, to reduce the severity of HGV driver injuries, or all-together prevent injuries from occurring. Additional research, including more PMHS testing, is recommended to establish these chest tolerance limits.
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| 9. |
- Holmqvist, Kristian, 1976, et al.
(författare)
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Heavy vehicle frontal sled crash test analysis chest deflection response in the Hybrid III dummy
- 2013
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Ingår i: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 18:2, s. 126-138
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to analyse the Hybrid III dummy chest loading in heavy vehicle frontal crashes. In total, eight truck front-to-trailer-type sled tests were performed. The Hybrid III, in driver position, was equipped with the chest deflection sensor system RibEye and its standard potentiometer sensor was compared with the RibEye deflection data. The chest impact point was established by using Fuji film impression, as well as from video data. Chest-to-steering wheel rim contact occurred in all tests. Differences in chest loading were found between the Hybrid III dummy reference test and the load case identified in this study, predominantly impact velocity, direction, distribution and location of loading. The steering wheel rim contact is the major contributor to chest deflection. The chest deformation consists of anterior/posterior compression and upward deflection of the sternal plate. The Hybrid III standard chest deflection sensor is not reliable in this load case due to the modes of sternal displacement and the single-point measurement location. Combining the RibEye system with global dummy kinematic data and accurate contact detection is required to fully assess chest deflection. New biomechanical data are needed to adapt the injury risk assessment to the identified load case.
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| 10. |
- Holmqvist, Kristian, 1976, et al.
(författare)
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Impacts to the chest of PMHSs – Influence of impact location and loaddistribution on chest response
- 2016
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 2016:87, s. 148-160
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Tidskriftsartikel (refereegranskat)abstract
- The chest response of the human body has been studied for several load conditions, but is not well known in the case of steering wheel rim-to-chest impact in heavy goods vehicle frontal collisions. The aim of this study was to determine the response of the human chest in a set of simulated steering wheel impacts. PMHS tests were carried out and analysed. The steering wheel load pattern was represented by a rigid pendulum with a straight bar-shaped front. A crash test dummy chest calibration pendulum was utilised for comparison. In this study, a set of rigid bar impacts were directed at various heights of the chest, spanning approximately 120 mm around the fourth intercostal space. The impact energy was set below a level estimated to cause rib fracture. The analysed results consist of responses, evaluated with respect to differences in the impacting shape and impact heights on compression and viscous criteria chest injury responses. The results showed that the bar impacts consistently produced lesser scaled chest compressions than the hub; the Middle bar responses were around 90 % of the hub responses. A superior bar impact provided lesser chest compression; the average response was 86 % of the Middle bar response. For inferior bar impacts, the chest compression response was 116 % of the chest compression in the middle. The damping properties of the chest caused the compression to decrease in the high speed bar impacts to 88 % of that in low speed impacts. From the analysis it could be concluded that the bar impact shape provides lower chest criteria responses compared to the hub. Further, the bar responses are dependent on the impact location of the chest. Inertial and viscous effects of the upper body affect the responses. The results can be used to assess the responses of human substitutes such as anthropomorphic test devices and finite element human body models, which will benefit the development process of heavy goods vehicle safety systems.
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