Effects of Vehicle Impact Velocity and Front-End Structure on Dynamic Responses of Child Pedestrians

2003 ◽  
Vol 4 (4) ◽  
pp. 337-344 ◽  
Author(s):  
Xuejun Liu ◽  
Jikuang Yang
Keyword(s):  
Impact Velocity ◽  
Dynamic Responses ◽  
Front End ◽  
Vehicle Impact

Effects of Vehicle Impact Velocity, Vehicle Front-End Shapes on Pedestrian Injury Risk

2012 ◽  
Vol 13 (5) ◽  
pp. 507-518 ◽  
Author(s):  
Yong Han ◽  
Jikuang Yang ◽  
Koji Mizuno ◽  
Yasuhiro Matsui
Keyword(s):  
Impact Velocity ◽  
Injury Risk ◽  
Front End ◽  
Pedestrian Injury ◽  
Vehicle Impact

scholarly journals A Study on Influence of Minivan Front-End Design and Impact Velocity on Pedestrian Thorax Kinematics and Injury Risk

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Fang Wang ◽  
Chao Yu ◽  
Guibing Li ◽  
Yong Han ◽  
Bingyu Wang ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Injury Risk ◽  
Research Work ◽  
Thoracic Injury ◽  
Chinese Market ◽  
Computational Biomechanics ◽  
Front End ◽  
Vehicle Impact ◽  
Pedestrian Impact ◽  
The Impact

Thoracic injuries occur frequently in minivan-to-pedestrian impact accidents and can cause substantial fatalities. The present research work investigates the human thoracic responses and injury risks in minivan-to-pedestrian impacts, when changing the minivan front-end design and the impact velocity, by using computational biomechanics model. We employed three typical types of minivan model of different front-end designs that are quite popular in Chinese market and considered four impact velocities (20, 30, 40, and 50 km/h). The contact time of car to thorax region (CTCTR), thorax impact velocity, chest deformation, and thoracic injury risks were extracted for the investigation. The results indicate that the predicted pedestrian kinematics, injury responses, and thoracic injury risks are strongly affected by the variation of the minivan front-end design and impact velocity. The pedestrian thoracic injury risks increase with the increasing vehicle impact velocity. It is also revealed that the application of the extra front bumper is beneficial for reducing the thoracic injury risk, and a relatively flatter minivan front-end design gives rise to a higher thoracic injury risk. This study is expected to be served as theoretical references for pedestrian protection design of minivans.

Injury biomechanics-based nondeterministic optimization of front-end structures for safety in pedestrian–vehicle impact

2021 ◽  
Vol 167 ◽  
pp. 108087
Author(s):  
Fei Lei ◽  
Xiaojiang Lv ◽  
Jianguang Fang ◽  
Tong Pang ◽  
Qing Li ◽  
...  
Keyword(s):  
Injury Biomechanics ◽  
Front End ◽  
Vehicle Impact

Effects of Vehicle Impact Velocity on Cyclist Injuries and Kinematics for Rear Impacts

2019 ◽  
pp. 281-288
Author(s):  
Ovidiu Andrei Condrea ◽  
Anghel Chiru ◽  
George Radu Togănel ◽  
Daniel Dragos Trusca
Keyword(s):  
Impact Velocity ◽  
Vehicle Impact ◽  
Rear Impacts

Effects of vehicle front-end safety countermeasures on pedestrian head injury risk during ground impact

2019 ◽  
Vol 233 (14) ◽  
pp. 3588-3599 ◽  
Author(s):  
Liangliang Shi ◽  
Yong Han ◽  
Hongwu Huang ◽  
Wei He ◽  
Fang Wang ◽  
...  
Keyword(s):  
Injury Risk ◽  
Rotation Angle ◽  
Head Injuries ◽  
Leading Edge ◽  
Vehicle Safety ◽  
Secondary Impact ◽  
Front End ◽  
Vehicle Impact ◽  
Safety Countermeasures ◽  
Primary Impact

Pedestrian safety countermeasures such as pop-up bonnets and exterior pedestrian airbags have been shown to decrease the pedestrian injury risk caused by vehicle impacts (primary impact). However, it is still unknown whether these devices could prevent or mitigate pedestrian injuries resulting from ground impacts (secondary impact). In order to understand how the vehicle safety countermeasures prevent pedestrian head injuries caused by primary and secondary impacts, a total of 252 vehicle-to-pedestrian impact simulations were conducted using the MADYMO code. The simulations accounted for three types of vehicle configurations (a baseline vehicle and vehicles with the two aforementioned vehicle safety countermeasures) along with five front-end structural parameters at three vehicle impact velocities (30, 40, and 50 km/h). The simulation results show that the bonnet leading edge height was the most sensitive parameter affecting the head-to-vehicle impact location and that caused different head injuries resulting from the local stiffness in the location impacted. Moreover, the bonnet leading edge height was the leading governing factor on the pedestrian rotation angle in the secondary impact. The vehicle equipped with a pop-up bonnet and an external airbag could cause a larger pedestrian rotation angle at 30 km/h than that in the other two vehicle types, but conversely could cause a smaller pedestrian rotation angle at 40 and 50 km/h. Also, the vehicle equipped with pop-up bonnet and external airbag systems could lead a higher pedestrian flight altitude than that of the baseline type. A vehicle equipped with a pop-up bonnet and external airbag systems provide improved protection for the pedestrian’s head in the primary impact, but may not prevent the injury risk and/or even cause more severe injuries in secondary impacts.

scholarly journals Realistic Reference for Evaluation of Vehicle Safety Focusing on Pedestrian Head Protection Observed From Kinematic Reconstruction of Real-World Collisions

2021 ◽  
Vol 9 ◽  
Author(s):  
Guibing Li ◽  
Jinming Liu ◽  
Kui Li ◽  
Hui Zhao ◽  
Liangliang Shi ◽  
...  
Keyword(s):  
Head Injury ◽  
Impact Velocity ◽  
Real World ◽  
Contact Time ◽  
Injury Risk ◽  
Safety Performance ◽  
Contact Boundary ◽  
Vehicle Safety ◽  
Pedestrian Protection ◽  
Vehicle Impact

Head-to-vehicle contact boundary condition and criteria and corresponding thresholds of head injuries are crucial in evaluation of vehicle safety performance for pedestrian protection, which need a constantly updated understanding of pedestrian head kinematic response and injury risk in real-world collisions. Thus, the purpose of the current study is to investigate the characteristics of pedestrian head-to-vehicle contact boundary condition and pedestrian AIS3+ (Abbreviated Injury Scale) head injury risk as functions of kinematic-based criteria, including HIC (Head Injury Criterion), HIP (Head Impact Power), GAMBIT (Generalized Acceleration Model for Brain Injury Threshold), RIC (Rotational Injury Criterion), and BrIC (Brain Injury Criteria), in real-world collisions. To achieve this, 57 vehicle-to-pedestrian collision cases were employed, and a multi-body modeling approach was applied to reconstruct pedestrian kinematics in these real-world collisions. The results show that head-to-windscreen contacts are dominant in pedestrian collisions of the analysis sample and that head WAD (Wrap Around Distance) floats from 1.5 to 2.3 m, with a mean value of 1.84 m; 80% of cases have a head linear contact velocity below 45 km/h or an angular contact velocity less than 40 rad/s; pedestrian head linear contact velocity is on average 83 ± 23% of the vehicle impact velocity, while the head angular contact velocity (in rad/s) is on average 75 ± 25% of the vehicle impact velocity in km/h; 77% of cases have a head contact time in the range 50–140 ms, and negative and positive linear correlations are observed for the relationships between pedestrian head contact time and WAD/height ratio and vehicle impact velocity, respectively; 70% of cases have a head contact angle floating from 40° to 70°, with an average value of 53°; the pedestrian head contact angles on windscreens (average = 48°) are significantly lower than those on bonnets (average = 60°); the predicted thresholds of HIC, HIP, GAMBIT, RIC, BrIC2011, and BrIC2013 for a 50% probability of AIS3+ head injury risk are 1,300, 60 kW, 0.74, 1,470 × 104, 0.56, and 0.57, respectively. The findings of the current work could provide realistic reference for evaluation of vehicle safety performance focusing on pedestrian protection.

Impact Crushing and Rebound of Thin-Walled Hollow Spheres

2013 ◽  
Vol 535-536 ◽  
pp. 40-43 ◽  
Author(s):  
Rong Hao Bao ◽  
T.X. Yu
Keyword(s):  
Impact Velocity ◽  
Analytical Modeling ◽  
Hollow Spheres ◽  
Rigid Wall ◽  
Coefficient Of Restitution ◽  
Dynamic Responses ◽  
Relative Thickness ◽  
Thin Walled ◽  
Impact Crushing ◽  
The Impact

The dynamic behavior of a thin-walled hollow sphere colliding onto a rigid wall has been studied by experiments, numerical simulation and analytical modeling, as reported in our previous papers. In the present paper, the impact crushing of metallic thin-walled hollow spheres onto rigid plates and the subsequent rebound are analyzed using finite element method. The effects of hollow sphere’s thickness-to-radius ratio, the material properties and the impact velocity on the dynamic responses are systematically investigated. The transition from axisymmetric dimpling to non-axisymmetric lobing is found to depend on the relative thickness of spheres and impact velocity; while the coefficient of restitution almost merely depends on impact velocity.

Experimental and Analytical Study of the Crashworthiness for the 2005 Ford GT Aluminum Spaceframe

2005 ◽  
Author(s):  
Ari G. Caliskan ◽  
Richard A. Jeryan ◽  
Huibert Mees ◽  
Simon Iregbu
Keyword(s):  
Automobile Industry ◽  
Light Weight ◽  
Rigid Barrier ◽  
Strain Behavior ◽  
Full Vehicle ◽  
Front End ◽  
Aluminum Castings ◽  
Vehicle Impact ◽  
Aluminum Profiles ◽  
6Xxx Series

The use of aluminum structures in the automobile industry have been increasing in the past decade due partly to the demand for light-weight vehicles, and in some instances, lower investment costs. In the case of the 2005 Ford GT, an aluminum spaceframe architecture was chosen. The spaceframe structure consists mainly of extruded 6xxx series aluminum profiles with aluminum castings acting as suspension attachment points. The aluminum castings, located at both the front and rear of the vehicle, also act as nodes to which a number of extrusions are welded. This architecture resulted in a very stiff, yet light-weight vehicle. In addition to stiffness and weight advantages, the use of both aluminum members and the spaceframe construction proved to have good crashworthiness properties for all impact modes. In this paper, the crash performance of the front end of the vehicle consisting of an extruded bumper and double-cell rail system is shown. Once the components were manufactured, specimen level tests were conducted to measure the stress-strain behavior of the extruded material. This information, along with the geometric data of the bumper and rails, was used to create models of the front-end of the vehicle. A series of analyses were conducted using a rigid barrier impact to determine crush loads as well as mode of collapse. Concurrently, the components were assembled and tested using a sled impact facility at speeds comparable to full vehicle impact speeds. The results of the component tests and the analyses showed that the models predicted both the crush loads as well as the crush modes accurately. This validation exercise proved to be key in creating accurate full vehicle models for all the crash modes that are required for certification of the vehicle. As such, development time as well as the number of full vehicle tests was reduced.

Dynamic response of a front end accessory drive system and parameter optimization for vibration reduction via a genetic algorithm

2016 ◽  
Vol 24 (11) ◽  
pp. 2201-2220 ◽  
Author(s):  
Hao Zhu ◽  
Yumei Hu ◽  
WD Zhu
Keyword(s):  
Genetic Algorithm ◽  
Dynamic Response ◽  
Flexural Rigidity ◽  
Optimization Method ◽  
Drive System ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Front End ◽  
Space Technique ◽  
External Forces

A typical engine front end accessory drive system (FEADS) is mathematically modeled through Hamilton’s principle and Newton’s second law. In this model, the belt’s flexural rigidity and pulley’s eccentricity are considered. Eccentricities of the pulleys are introduced into governing motion equations of the belt spans through the boundary conditions and then transformed to external forces acting on the belt spans. Vibration modes and natural frequencies of the FEADS are calculated by the state-space technique of the complex mode theory. Dynamic responses of the FEADS at different rotational rates of the crankshaft are calculated by solving the spatially discretized governing equations obtained by Galerkin method. The modeling and solution methods are formulated and programmed in a general purposed code. The study shows that the typical resonance and beat phenomenon happen in a certain portion of the belt spans at a certain rotational rate by the excitations of the pulley’s eccentricity. According to the modal analysis and dynamic response analysis, an optimization method based on a genetic algorithm is proposed. By comparing the vibration amplitudes of belt spans before and after optimization at different rotational rates, this optimization method is verified to be effective in reducing transverse vibrations of the belt spans.

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