| 1. |
- Huang, Sunan, 1979, et al.
(author)
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A Reversible Bumper System for Protecting Pedestrian Lower Limbs from Car Collisions
- 2010
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In: International Journal of Vehicle Design. - 1741-5314. ; 53:4, s. 288-299
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Journal article (peer-reviewed)abstract
- This study investigated the performance of a Reversible Bumper System (RBS) for protecting pedestrian lower limbs from car collisions. The Finite Element (FE) model of the RBS was developed based on a validated car front FE model. The FE models of a lower legform impactor and a pedestrian lower limb were used to investigate the performance of the RBS model at different impact conditions. It was finally determined that the RBS performance can be improved by reducing bumper stiffness; however, this performance is impaired in the bumper deploying process by the speed of 2.5 m/s or greater.
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| 2. |
- Huang, Sunan, 1979
(author)
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A Study of an Integrated Safety System for the Protection of Adult Pedestrians from Car Collisions
- 2010
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Doctoral thesis (other academic/artistic)abstract
- This study aimed to evaluate and improve the performance of a newly developed safety system intended to protect pedestrians during frontal car collisions. This system includes a remote sensor system, a contact sensor, a reversible bumper system (RBS), and a reversible hood (RH).The remote sensor system was evaluated for its ability to detect pedestrians at risk in a vehicular traffic environment. In this assessment, car-pedestrian accident scenarios were analyzed based on the cases selected from the Swedish TRaffic Accident Data Acquisition (STRADA) database. The two most common scenarios were identified as cars entering and leaving intersections, and colliding with pedestrians crossing the road. The accident data for these two scenarios were then investigated in terms of specific factors, such as the trajectory and velocity of the pedestrians and cars involved. Based on the accident data, a mathematical model was presented, and the remote pedestrian sensor system was evaluated using this model.The contact sensor was analyzed for the temperature-independent measurement of pedestrian impacts. A baseline bumper finite element (FE) model was initially developed and validated using the European New Car Assessment Program (EuroNCAP) lower legform impact tests performed on the production bumper. Based on the baseline bumper model, an improved bumper model was subsequently developed to meet the acceptance requirements of the European Enhanced Vehicle–safety Committee Working Group 17 (EEVC WG17) lower legform impact tests. A lower limb FE model was then developed and used to evaluate further the protective performance of the baseline and improved bumper models. Finally, the contact sensor was incorporated into the improved bumper model, and a performance study was conducted to evaluate its performance in terms of temperature stability and mass sensitivity of the sensor output.The performance of the RBS was investigated for the protection of pedestrians’ lower limbs during bumper collisions. The detailed FE model of a production car front was developed and validated based on the EuroNCAP lower legform impact tests performed on the production car front. Next, a model RBS was developed to replace the original bumper in the car front model. In order to investigate the performance of the RBS, the lower limb model and the EEVC WG17 lower legform model were used to collide with the RBS model of different design configurations under various impact conditions. Finally, the effects of the design parameters on the protective performance of the RBS were calculated using the statistical method for factorial experiment design.The RH was evaluated and optimized for the prevention of head injuries among adult pedestrians from hood collisions. The car front FE model was validated based on the EuroNCAP adult headform impact tests conducted on the car hood. The baseline RH was subsequently developed from the original hood of the validated car front model. The FE models of a 50th percentile human head and the EEVC WG17 adult headform were used in parallel to evaluate the protective performance of the baseline RH. In order to minimize the Head Injury Criterion (HIC) values of the headform model, the response surface method was applied to optimize the RH in terms of material stiffness, lifting speed and lifted height. Finally, the headform and human head models were once again used to evaluate the protective performance of the optimized RH.The results of this study indicated that the remote sensor system can detect almost all visible pedestrians in the two most common scenarios in a timely manner when the detection angle is greater than 60 degrees. The contact sensor can also identify pedestrian impacts with the car bumper. Moreover, enhanced sensor output stability and mass sensitivity can be achieved by using a 25 mm rather than 50 mm sensor tube. The RBS performance can be improved by reducing bumper stiffness; however, such performance is impaired in the bumper-deploying process at speeds of 2.5 m/s or greater. Less than 150 mm, the deployment distance of the RBS has no influence on the bumper protective performance. Compared with the retracted and lifting baseline RH, the lifted baseline RH can definitely minimize the injury parameters of the headform and human head models. When the optimized RH is lifted, the Head Injury Criterion (HIC) values of the headform and human head models are reduced to much lower than 1,000. Thus, the risk of pedestrian head injuries can be prevented as required by EEVC WG17.
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| 3. |
- Huang, Sunan, et al.
(author)
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An investigation on child occupant safety in passenger vehicles based on accident data from Changsha, China
- 2013
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In: Proceedings - 2013 5th Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2013. - 9780769549323 ; , s. 218-221
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Conference paper (peer-reviewed)abstract
- The objective of this study is to determine the traffic safety situation of child occupants in the urban areas of Changsha, China. For this purpose, accident data were collected from the local traffic police authority. The selected samples have been dated from January 1,2001 to December 31,2010, durich which 1, 629 traffic accidents involving children occurred in Changsha. A total of 331 child occupants up to 15 years of age were identified in these accidents. A statistical analysis was then conducted in terms of the accident type, accident scenario, child age, gender, injury region, and injury severity. The results indicate that the side impact is the most common accident scenario in the child occupant accidents, accounting for 45% of all the cases. The major type of the accidents is the double-vehicle crashes in which passenger vehicles account for 73.4%. No child restraint system (CRS) was identified in the selected accidents. The head and extremity injuries have a high frequency in the child injuries. With the implementation of safey regulations, common knowledge about the traffic safety for child occupants should be strengthen, and CRS will be required in cars to protect child occupants.
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| 4. |
- Huang, Sunan, 1979, et al.
(author)
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Analysis of Car-Pedestrian Impact Scenarios for the Evaluation of a Pedestrian Sensor System Based on Accident Data from Sweden
- 2006
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In: Expert Symposium on Accident Research.
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Conference paper (other academic/artistic)abstract
- There is a need for detecting characteristics of pedestrian movement before car-pedestrian collisions to trigger a fully reversible pedestrian protection system. For this purpose, a pedestrian sensor system has been developed. In order to evaluate the effectiveness of the sensor system, the in-depth knowledge of car-pedestrian impact scenarios is needed. This study aims at the evaluation of the sensor system. The accident data are selected from the STRADA database. The accident scenarios available in this database were evaluated and the knowledge of the most common scenarios was developed in terms of the pedestrian trajectory, the pedestrian speed, the car trajectory, the car velocity, etc. A mathematical model was then established to evaluate the sensor system with different detective angles. It was found that in order to detect all the pedestrians in the most common scenarios on time the sensor detective angle must be kept larger than 60 degrees.
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| 5. |
- Huang, Sunan, 1979
(author)
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Analysis of Sensing Systems for the Detection of Pedestrian Impacts
- 2008
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Licentiate thesis (other academic/artistic)abstract
- In order to reduce pedestrian casualties in vehicle traffic accidents, safety countermeasures, for example the active hood system and external airbag system, have been proposed to protect pedestrians in vehicle collisions. Such a protection system must consist of a sensing system to detect the pedestrian impact and/or the potential impact. It is a key issue to verify the effectiveness of the detection system. The aim of this study is to evaluate the performance of a remote sensing system and a contact sensor for the detection of pedestrian impacts.In paper I, a remote sensing system was evaluated for the pedestrian detection in vehicle traffic environment. In this study, the car-pedestrian accident data were selected from the Swedish Traffic Accident Data Acquisition (STRADA), a database developed by collecting accident data from the police and hospitals. In this database, 9 scenarios of car-pedestrian accidents were defined according to pedestrian and car trajectories and accident locations. A total of 2,199 car-pedestrian impacts with identified accident scenarios were selected from the database and further analyzed in this study. Based upon the analysis, the two most common scenarios–accounting for 46.8 percent of all the cases–were identified as cars entering and leaving intersections colliding with pedestrians crossing the road. Based on this understanding, the knowledge of these two scenarios was developed in terms of the trajectories and speeds of pedestrians and cars: the qualitative pedestrian and car trajectories were described by the definition of the accident scenarios, while the quantitative speeds of pedestrians and cars were estimated based on pedestrian ages and road speed limits. By using both the qualitative and quantitative data, a mathematical model was presented with the hypothesis that all the pedestrians in both scenarios were not obstructed. The effectiveness of the sensing system for the detection of potential pedestrian collisions was then evaluated by using this model.In paper II, a new pedestrian air-tube contact sensor in the car bumper was developed at Autoliv Research due to that a traditional contact sensor can be unstable at varying temperatures. This paper aimed to evaluate the new contact sensor for the temperature-independent measurement of pedestrian impacts. First, the baseline FE bumper model of a production car was developed and validated according to the EuroNCAP lower legform impact tests performed on the car bumper. The results of the validation analysis were comparable with the test results, but they have exceeded the limits of the EEVC WG17 lower legform impact tests. The baseline bumper model was therefore considered as valid, but it required an enhanced safety performance. Based on the baseline model, an improved bumper model was subsequently developed to meet the EEVC requirements. Following the EEVC test methods, the legform impact simulations were conducted in the middle and on the left and right sides of the improved bumper model, resulting in the maximum legform responses of tibia accelerations from 117 to 139 g and knee bending angle from 7.7 to 9.3 degree, thereby meeting the EEVC requirements. Second, a FE human lower extremity model was developed; the baseline and improved bumper models were further evaluated using this human model. The improved model was shown to protect the human knee joint effectively, but the risks of tibia and fibula fractures were increased. Finally, the contact sensor was built into the improved bumper model and an analysis was conducted to evaluate the sensor performance.From paper I, it was concluded that the sensing system can detect almost all the pedestrians in the two scenarios, if the detective angle of the system is greater than 60 degrees. From paper II, it was determined that using a 25-mm instead of 50-mm air-tube sensor resulted in more stable sensor output at varying temperatures in the EEVC WG17 legform impacts; moreover the sensor was more sensitive to the different masses of the impact objects. The 25-mm air-tube sensor was thus a better choice for the contact sensor design.
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| 6. |
- Huang, Sunan, 1979, et al.
(author)
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Assessment of a Safe Bumper System Using a Pedestrian Lower Limb FE Model
- 2009
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In: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Conference paper (peer-reviewed)abstract
- Lower limb injuries are common result of car-to-pedestrian impacts. A reversible bumper system was developed to reduce the risk of such injuries. In order to improve the protective performance of the bumpersystem, it was necessary to investigate the efficiency of the bumper system at different impact conditions and design configurations.In this study, the protective performance of the reversible bumper system was assessed by finite element (FE)modeling of lower limb impacts. The FE model of a production car front was developed and validated. The FE model of the reversible bumper system was then developed and replaced the original bumper in the car front model. A human lower limb FE model was used to evaluate the protective performance of the reversible bumper system. The effects of the bumper design parameters on protective performance were investigated by using the statistical method of factorial experiment design.The injury responses of tibia acceleration, knee bending angle and shearing displacement were measured from the lowerlimbmodel. The injuries of knee ligament avulsions and long bone fractures were also obtained from impact simulations. By comparing the protective performance of the reversible bumper system at different impact conditions and design configurations, it was concluded that the bumper protective performance can be improved by reducing bumper stiffness; however, this performance can be impaired in the bumper deploying process by the speed of 2.5 m/s or greater.
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| 7. |
- Huang, Sunan, 1979, et al.
(author)
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Evaluation of Remote Pedestrian Sensor System Based on the Analysis of Car-Pedestrian Accident Scenarios
- 2008
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In: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 46:9, s. 1345-1355
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Journal article (peer-reviewed)abstract
- There is a need to evaluate the effectiveness of a remote sensor system for pedestrian detection in a vehicle traffic environment. For this purpose, the car-pedestrian accident scenarios were analyzed using selected data from the Swedish Traffic Accident Data Acquisition (STRADA), a database developed by collecting accident data from the police and hospitals. The two most common scenarios were identified as cars entering and leaving intersections colliding with pedestrians crossing the road. The knowledge of these two scenarios was then developed in terms of the factors such as the pedestrian’s trajectory, the pedestrian’s speed, the car’s trajectory and the car’s velocity. Based on the developed knowledge, a mathematical model was presented and the remote pedestrian sensor system was evaluated by using this model. It was found that the sensor system can detect almost all the pedestrians in these two scenarios in time, in the case where the detective angle was larger than 60 degrees.
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| 8. |
- Huang, Sunan, 1979, et al.
(author)
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Optimization of a Reversible Hood for Protecting a Pedestrian's Head during Car Collisions
- 2010
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In: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 42:4, s. 1136-1143
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Journal article (peer-reviewed)abstract
- This study evaluated and optimized the performance of a reversible hood (RH) for the prevention of the head injuries of an adult pedestrian from car collisions. The FE model of a production car front was introduced and validated. The baseline RH was developed from the original hood in the validated car front model. In order to evaluate the protective performance of the baseline RH, the FE models of an adult headform and a 50th percentile human head were used in parallel to impact the baseline RH. Based on the evaluation, the response surface method was applied to optimize the RH in terms of the material stiffness, lifting speed, and lifted height. Finally, the headform model and the human head model were again used to evaluate the protective performance of the optimized RH. It was found that the lifted baseline RH can obviously reduce the impact responses of the headform model and the human head model by comparing with the retracted and lifting baseline RH. When the optimized RH was lifted, the HIC values of the headform model and the human head model were further reduced to much lower than 1000. The risk of pedestrian head injuries can be prevented as required by EEVC WG17.
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| 9. |
- Huang, Sunan, 1979, et al.
(author)
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Performance Analysis of a Bumper-Pedestrian Contact Sensor System by Using FE Models
- 2008
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In: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 13:2, s. 149-157
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Journal article (peer-reviewed)abstract
- A pedestrian contact sensor in the car bumper is a potential solution to trigger an active hood system. Because of the high level of temperature dependency for the bumper foam stiffness, the sensor output can be unstable at varying temperatures. A new contact sensor was therefore developed to provide a temperature-independent measurement for pedestrian impacts.This study analyzed the performance of the bumper-pedestrian contact sensor system. First, a baseline Finite Element (FE) bumper model of a production car was developed and validated. Based on the baseline model, an improved bumper model was subsequently developed to meet the requirements of the lower legform impact tests proposed by Working Group 17 of the European Enhanced Vehicle-safety Committee (EEVC WG17). Second, a FE human lower extremity model was developed. Using this model, the baseline and improved bumper models were further evaluated in terms of the predicted knee ligament raptures and long bone fractures. Finally, the new contact sensor was built into the improved bumper model. A performance study was then conducted to evaluate the sensor effectiveness. Consequently, a better diameter for the sensor tube was identified in terms of the temperature stability and mass sensitivity of the sensor output.
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