| 1. |
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| 2. |
- Chen, X., et al.
(författare)
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Optimization of longitudinal beam for improvement of crashworthiness in frontal and offset impacts
- 2012
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Ingår i: 2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012. Guilin, Guangxi, 31 July - 2 August 2012. - 9780769547725 ; , s. 582-585
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Konferensbidrag (refereegranskat)abstract
- The aim of the study is to optimize the longitudinal beam based on 100% overlapping rigid barrier ( 100% RB ) impact and 40% overlapping offset deformable barrier ( 40% ODB ) impact. The 100%RB and 40%ODB impact FE models were developed in LS-DYNA and validated by using results from crash tests. According to the requirement of crashworthiness, the peak of acceleration of left B-pillar and energy absorbed per unit mass of longitudinal beam were chosen as optimization objects, and the thicknesses of four parts of the longitudinal beam were considered as the design variables. Furthermore, uniform design was applied to build variable samples. Optimal results were obtained by surrogate model built by Kriging and optimization method NSGA-II (Non-Dominated Sorting in Genetic Algorithms-II). The results showed that 100%RB and 40%ODB impact should be considered together when longitudinal beam was designed. The optimized longitudinal beam matches well and effectively improves vehicle crashworthiness.
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| 3. |
- Chen, Yong, et al.
(författare)
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A Study on Head Injury Risk in Car-to-Pedestrian Collisions Using FE-Model
- 2009
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- Head injury is quite frequently occurred in car-to-pedestrian collisions, which often places an enormous burden to victims and society. To address head protection and understand the head injury mechanisms, in-depth accident investigation and accident reconstructions were conducted. A total of 6 passenger-cars to adult-pedestrian accidents were sampled from the in-depth accident investigation in Changsha China. Accidents were firstly reconstructed by using Multi-bodies (MBS) pedestrian and car models. The head impact conditions such as head impact velocity; position and orientation were calculated from MBS reconstructions, which were then employed to set the initial conditions in the simulation of a head model striking a windshield using Finite Element (FE) head and windshield models. The intracranial pressure and stress distribution of the FE head model were calculated and correlated with the injury outcomes. Reconstruction results show that the coup/contre-coup pressure, Von Mises stress and shear stress are important physical parameters to predict the brain injury risks.
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| 4. |
- Guo, Q., et al.
(författare)
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A study on protecting of the far side occupants based on road traffic accident reconstruction
- 2012
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Ingår i: 2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012. Guilin, Guangxi, 31 July - 2 August 2012. - 9780769547725 ; , s. 140-143
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Konferensbidrag (refereegranskat)abstract
- A study on injuries of far side passenger in vehicle side impact was carried out by using a real road accident. Firstly, the trace of the accident car was reproduced using PC-Crash code. The impact velocity of the passenger car calculated from PC-Crash was used as the input data for MADYMO modeling of occupant kinematics. Then the dynamic responses of the occupants were analyzed using the calculated injury parameters of the driver. Furthermore, LS-DYNA code was used to simulate the impact between the head of the driver and the left shoulder of the occupant. In the end, a MADYMO model with an airbag between driver and occupant was developed, and the protective efficiency of the airbag was showed by comparing the models with and without airbag.
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| 5. |
- Guo, W., et al.
(författare)
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Effects of bull bars on head and lower extremity injuries in vehicle-pedestrian collision
- 2012
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Ingår i: 2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012. Guilin, Guangxi, 31 July - 2 August 2012. - 9780769547725 ; , s. 356-359
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Konferensbidrag (refereegranskat)abstract
- This study aimed to investigate the effect of bull bar on injuries of pedestrian head and lower extremities based on accident reconstructions and parameters analysis. Four real-world accidents with detailed information were reconstructed via simplified vehicle-pedestrian collision models (two of which with bull bars) in MADYMO. The injury mechanisms of pedestrians caused by bull bar were analyzed, comparing with non-bull-bar vehicle. Moreover, a pedestrian-friendly bull bar was proposed considering the influence of structures of bull bars on pedestrian injuries. The results of accidents reconstructions indicated that the rigid bull bar caused high risk of injuries on lower extremities. The design parameters, such as the height and leading length of upper bull bar had remarkable influences on the injury severity of head.
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| 6. |
- Han, Y., et al.
(författare)
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A study on chest injury mechanism and the effectiveness of a headform impact test for pedestrian chest protection from vehicle collisions
- 2012
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 50:5, s. 1304-1312
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Tidskriftsartikel (refereegranskat)abstract
- This study was aimed at investigating the injury mechanism of pedestrian chests in collisions with passenger vehicles of various frontal shapes and examining the influence of the local structural stiffness on the chest injury risk by using the headform impact test at the chest contact area of the vehicle. Three simulations of vehicle to pedestrian collisions were conducted using three validated pedestrian finite element (FE) models of three pedestrian heights of 177 (AM50th), 165 and 150 cm and three FE vehicles,models representing a one-box vehicle, a minicar and a medium car. The validity of the vehicle models was evaluated by comparing the headform acceleration against the measured responses from headform impact tests. The chest impact kinematics and the injury mechanisms were analyzed in terms of the distribution of the von Mises stress of the ribcage and in terms of the chest deflections. The chest contact locations on the front panel and the bonnet top were identified in connection to the causation of rib fractures. The risk of rib fractures was predicted by using the von Mises stress distribution. The headform impact tests were carried out at the chest contact area on the front panel and bonnet to examine the safety performance with respect to pedestrian chest protection. In simulations of the one-box vehicle to pedestrian collisions, the chest was struck directly by the frontal structure at a high velocity and deformed substantially, since a shear force was generated by the stiff windshield frame. The acceleration of the headform was related to the rib deflections. The injury threshold of the ribcage deflection (42 mm) corresponded to the headform average acceleration of 68G. In the minicar collision, the chest was struck with the bonnet top and cowl area at a low velocity, and the deformation was small due to the distributed contact force between the chest and the bonnet top. Besides, the ribcage deformation was too small for bridging a relation between the headform accelerations and rib deflections. In the medium car collision, the deformation mode of the chest was similar to that in the minicar collision. The chest collided with the bonnet top at a low velocity and deformed uniformly. The deflection of the ribs had an observable correlation with the headform accelerations measured in the headform impact tests. The frontal shape of a vehicle has a large influence on a pedestrian's chest loadings, and the chest deformation depends on the size of the pedestrian and the stiffness of the vehicle. The one-box passenger vehicle causes a high chest injury risk. The headform impactor test can be utilized for the evaluation of the local stiffness of a vehicle's frontal structure. The reduction of the headform acceleration is an effective measure for pedestrian chest protection for specific shapes of vehicles by efficacy in modifying the local structural stiffness.
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| 7. |
- Han, Yong, et al.
(författare)
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Effects of Vehicle Impact Velocity on Pedestrian Fatal Injury Risk
- 2011
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Ingår i: Chinese Journal of Automotive Engineering. - 2095-1469. ; 1:4, s. 399-406, DOI: 10.3969/j.issn.2095-1469.2011.04.020-
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the vehicle speed and vehicle front shape on pedestrian fatal injury risk was investigated. The THUMS pedestrian and four vehicle FE models with different front-ends (medium sedan, minicar, one-box vehicle and SUVs) was used. The pedestrian injury risk was analyzed at speed 20, 30, 40 and 50 km/h. The results demonstrate that the impact speed and vehicle front shape are two important factors influence of the pedestrian kinematics and injuries. A significant reduction of all injuries can be achieved if the impact speed is less than 30 km/h. Head was at high injury risk in medium sedan and SUV collisions. Chest injuries risk was particular high in one-box vehicle impacts. In the minicar collision, the injury risk was the smallest if head without contact to the A-pillar. The design tendency of short front-end and wide windscreen area can be achieved the protection of the pedestrian from fatalities.
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| 8. |
- Han, Y., et al.
(författare)
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Effects of Vehicle Impact Velocity, Vehicle Front-End Shapes on Pedestrian Injury Risk
- 2012
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 13:5, s. 507-518
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study aimed at investigating the effects of vehicle impact velocity, vehicle front-end shape, and pedestrian size on injury risk to pedestrians in collisions with passenger vehicles with various frontal shapes. Method: A series of parametric studies was carried out using 2 total human model for safety (THUMS) pedestrian models (177 and 165 cm) and 4 vehicle finite element (FE) models with different front-end shapes (medium-size sedan, minicar, one-box vehicle, and sport utility vehicle [SUV]). The effects of the impact velocity on pedestrian injury risk were analyzed at velocities of 20, 30, 40, and 50 km/h. The dynamic response of the pedestrian was investigated, and the injury risk to the head, chest, pelvis, and lower extremities was compared in terms of the injury parameters head injury criteria (HIC), chest deflection, and von Mises stress distribution of the rib cage, pelvis force, and bending moment diagram of the lower extremities. Result: Vehicle impact velocity has the most significant influence on injury severity for adult pedestrians. All injury parameters can be reduced in severity by decreasing vehicle impact velocities. The head and lower extremities are at greater risk of injury in medium-size sedan and SUV collisions. The chest injury risk was particularly high in one-box vehicle impacts. The fracture risk of the pelvis was also high in one-box vehicle and SUV collisions. In minicar collisions, the injury risk was the smallest if the head did not make contact with the A-pillar. Conclusion: The vehicle impact velocity and vehicle front-end shape are 2 dominant factors that influence the pedestrian kinematics and injury severity. A significant reduction of all injuries can be achieved for all vehicle types when the vehicle impact velocity is less than 30 km/h. Vehicle designs consisting of a short front-end and a wide windshield area can protect pedestrians from fatalities. The results also could be valuable in the design of a pedestrian-friendly vehicle front-end shape.
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| 9. |
- Han, Y., et al.
(författare)
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Finite element analysis of kinematic behaviour and injuries to pedestrians in vehicle collisions
- 2012
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Ingår i: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 17:2, s. 141-152
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Tidskriftsartikel (refereegranskat)abstract
- In vehicle-to-pedestrian collisions, the characteristics of a vehicle's frontal shape and structural stiffness have a significant influence on the kinematics and injury risk of the pedestrian's body regions. In the present study, the kinematic behaviour and injury risk of the pedestrians were investigated in collisions against vehicles with different frontal shapes. The THUMS (Total HUman Model for Safety) pedestrian finite element (FE) model was used and impacted by three different types of vehicle FE models (passenger car, one-box vehicle and sport-utility vehicle [SUV]) representing the different frontal shapes at 40 km/h. In the simulation with the passenger car-to-pedestrian impact, the pedestrian wrapped around the hood, and the resulting bending moment of the lower extremity and head injury criterion (HIC) value were high. In the simulation with the one-box vehicle-to-pedestrian impact, the pedestrian's upper torso was directly hit by the front end of the vehicle. The pelvis and chest had contact with the stiff vehicle frontal panel, resulting in a high stress being observed on the rib cage. In the simulation with the SUV-to-pedestrian impact, the force of the pelvis was high due to the contact with the vehicle hood's leading edge. The results indicated that the frontal shape of the vehicle has a large effect on the pedestrian kinematic behaviour, including the impact velocity of the pelvis, chest, and head against the vehicle. Moreover, the stiffness of the vehicle structure can affect the deformation mode of the human body segments, such as the lower extremities and the rib cage. The injury predictions for each body region from the FE analyses agreed with observations from pedestrian accidents involving a car, one-box vehicle and SUV, respectively.
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| 10. |
- Han, Yong, et al.
(författare)
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Finite Element Analysis of Lower Extremity Fractures in Vehicle-Pedestrian Collision
- 2011
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Ingår i: Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition). - 1671-5497. ; 41:1, s. 6-11，id.1671-5479(2011)01-0006-06-
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Tidskriftsartikel (refereegranskat)abstract
- A finite element Human Body Model (HBM) of lower extremity was improved based on the geometry of human skeleton anatomy. The model consists of the pelvis, the femur, the tibia, the fibula, the patella, the foot bones, primary tendons, knee joint capsule, meniscus, and ligaments. This model is constructed using shell and solid elements also including linear spring-damper elements, it contains of 29777 nodes and 30873 elements. The whole model was validated by comparing the results of simulation with these from shearing-bending cadaver tests described in literature. Then the FE HBM of lower extremity and an existing multi-body system (MBS) human model of the pedestrian were used to reconstruct the real-world vehicle-pedestrian accident and lower limb injuries. Results of injury reconstruction show that this FE model has a good biofidelity and biomechanical response, and can be applied in research on lower limb injury mechanisms and used in the development of injury protective devices.
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