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• 2010, Vol. 1 No. 4
  Published on:20 December 2010 Previous issue    Next issue

  Injury tolerance and mechanism of lower extremity in#br# automobile impact accidents

  CHEN Hai-Bin, WANG Zheng-Guo, Albert I King, Liying ZHANG

  2010, 1(4):  253-259.  doi:10.3969/j.issn.1674-8484.2010.04.001

  Abstract ( 2193 )   PDF (1447KB) ( 2065 )  

  A review about injury tolerance and injury mechanism of lower extremity is given to conduct the experimental studies
  and numerical modeling for automobile impact accidents. Data sources were selected from Weber (1859, cadaver femur threepoint
  bending tests) to as recent as Kerrigan (2009, multibody modeling of pedestrian lower extremity). One epidemiological
  investigation was described where lower extremity injuries are found to be the common form of injury associated with automobile
  impact accidents, generally with massive soft tissue tear or defect and severe bone fracture or dislocation. Injury tolerance of the
  commonly-injured regions of the lower extremities, including femur, patella, knee, tibia, and ankle, was depicted primarily in terms
  of the peak axial compressive force or bending/torsional moment for static and dynamic conditions. The injury mechanism of
  following injury patterns is summarized including knee joint injury, long bone shaft fracture, femoral neck fracture, femoral condyle
  fracture, ankle joint injury, and foot bone fracture.

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  PEM Fuel Cells: Current Status and Challenges for Electrical#br# Vehicle Applications

  LI Bing, LI Hui, MA Jian-Xin, WANG Hai-Jiang

  2010, 1(4):  260-269.  doi:10.3969/j.issn.1674-8484.2010.04.002

  Abstract ( 3208 )   PDF (1740KB) ( 4140 )  

  Proton exchange membrane (PEM) fuel cell technology has already made tremendous advances. However,
  performance, cost, and durability remain the key problems before PEM fuel cells can be successfully commercialized. This
  paper is a review of current status in the study of PEM fuel cells and the existing challenges for their use in electrical vehicle
  (EV) applications,basedon a survey of the published literature. In reviewing the current status, we introduce presentstate-ofthe-
  art PEM fuel cell technology for EV applications and look at key technical achievements. PEM fuel cell research has made
  particularly significant progress in improving performance, cost, and durability, primarily focusing on the main components of
  the stack and system. Nonetheless, commercialization of fuel cell electrical vehicle (FCEV) applications is still confronted with
  performance, cost, and durability hurdles, hindering the achievement of the 2010/2015 US DOE (Department of Energy) targets.
  The maintenance of fuel cell vehicles as another component of their future commercializationwas also reviewed.

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  Automotive Safety

  Frontal Crash Sled Simulation with Elderly Human Body#br# Model for the Optimal Restraint System Design

  CHOI Hyung Yun, LEE Inhyeok

  2010, 1(4):  270-274.  doi:10.3969/j.issn.1674-8484.2010.04.003

  Abstract ( 2537 )   PDF (1979KB) ( 2294 )  

   A numerical frontal impact sled model was constructed and simulated consisted of driver side cockpit and elderly
  human body for an optimal design of restraint system, i.e., air bag and seat belt. The objective function in the optimization process
  was to minimize the chest injury risk while keeping the other injury risks (i.e., head injury criterion (HIC) and femur load) under
  the thresholds. There were three design variables for the restraint, i.e., peak force of belt load limiter, deployment time of belt
  pretensioner/airbag, and the vent hole size. The results show that the smaller size of vent hole, earlier firing of belt pretensioner/
  airbag and lower belt limit load are needed to reduce the chest injury risk of elder driver in a front crash by comparing with the
  restraint design for the younger population.

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  Injury and related factors in vehicle-pedestrian and vehiclecyclist#br# collisions

  XU Dang, ZHU Xi-Chan, MA Zhi-Xiong

  2010, 1(4):  275-282.  doi:10.3969/j.issn.1674-8484.2010.04.004

  Abstract ( 1820 )   PDF (2604KB) ( 1807 )  

  Pedestrians and cyclists are the most vulnerable road users in traffic crash in China, so the related research is of
  important significance. Vehicles were classified into three types, Sedan, SUV, the Onebox, according to IHRA (International
  Harmonized Research Activities). A vehicle-pedestrian collision model and a vehicle-cyclist collision model were built using the
  MADYMO program to simulate and analyze the relate factors influencing the head and lower leg injury parameters and kinematic
  parameters, such as the horizontal distance, the wrap around distance (WAD), and the motion state of pedestrians and cyclists.
  Relative curves of injury parameters and velocities were obtained based on the simulated parameters with the logistic regression
  model. The results show that vehicle impact velocities, vehicle geometries, pedestrian and cyclist figures, initial impact locations,
  and initial impact angles are major influential factors, with different injury risks and kinematics for pedestrians and cyclists.

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  Heart rate variability of pilots and passenger unders impact#br# and vibration circumstances

  ZOU Meng, XU Shu-Cai, ZHANG Jin-Huan, RU Jia-Liang, HUANG Shi-Lin

  2010, 1(4):  283-287.  doi:10.3969/j.issn.1674-8484.2010.04.005

  Abstract ( 1686 )   PDF (1602KB) ( 1951 )  

  The influence of impact and vibration on the personnel heart rate variability (HRV) was studied using biomedical
  monitoring equipment to protect the driver and passenger security. Impact tests show that the heart rate increases by 1.4% to
  44.3% with decreasing rMSSD (root mean square successive difference), LF (low frequeuce), and HF (high frequence), but
  increasing LF/HF. Vibration tests show that the average heart rates of the driver and co-driver increase by 12.6% and 4.8% after
  one hour's driving, with the rMSSD, LF, and HF being decreased, but the LF/HF being increased. The results indicate that the
  activities of the sympathetic nerve and pneumogastric nerve are weakened, and the psychological tensity trend is enhanced with
  increasing age and responsibility. Therefore, the HRV can be used to analyze the tension, fatigue as well as security monitoring,
  with broad prospects for application and research.

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  Energy absorption characteristics of PVB windshield subjected#br# to human head impact

  LIU Bo-Han, ZHU Meng-Yi, SUN Yue-Ting, XU Jun, LI Yi-Bing

  2010, 1(4):  288-291.  doi:10.3969/j.issn.1674-8484.2010.04.006

  Abstract ( 2293 )   PDF (1950KB) ( 2332 )  

  In traffic accidents, the energy absorption ability of windshield has an important influence on the protection of human
  head. Quasi-static compression test with polyvinyl butyral (PVB) laminated glass was carried out to acquire its stress-strain
  relationship. With the test result embedded, finite element model was established using Ls-Dyna. Mechanic behavior of the PVB
  laminated windshield under human head impact was studied, with kinetic absorptance of the windshield defined to investigate the
  absorption ability of the windshield for different impact conditions. The results show that the windshield can absorb more energy
  with impact velocities of 5—7.5 m/s and impact angles of 15°—45°, while the impact position has slight influence.

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  Design of the engine sandwich bonnet based on the head resultant#br# acceleration waveform

  DONG Li-Ping, ZHU Xi-Chan, MA Zhi-Xiong, ZHANG Yi-Chuan

  2010, 1(4):  292-296.  doi:10.3969/j.issn.1674-8484.2010.04.007

  Abstract ( 2332 )   PDF (2243KB) ( 1860 )  

  The head resultant acceleration waveform was adjusted to meet the design requirements of the sandwich bonnet with
  honeycomb material to improve the head protection performance during pedestrian impact. The basic extreme conditions of HIC
  (head injury criterion) interval were deduced for the actual head acceleration waveform. The response surface of the HIC value
  and head displacement and the physical parameters of the honey-composite material used in the engine hood which meet the
  extreme conditions were obtained according to the optimal acceleration waveform theory, using the MADYMO and HyperStudy
  softwares. The results show that the resultant acceleration waveform can satisfy the actual design target by changing the
  Young’s modulus and densification strain of the sandwich composite material.

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  Influence of the vehicle front sculpt and bumper foam on#br# pedestrian leg injury index

  ZHAO Zheng, CHEN Chao-Zhuo, WU Shen-Rong

  2010, 1(4):  297-306.  doi:10.3969/j.issn.1674-8484.2010.04.008

  Abstract ( 2299 )   PDF (3410KB) ( 2325 )  

   In pedestrian-car impact, front bumper materials, the vehicle sculpt, package and layout play a key role in pedestrian
  leg protection. The stress and injury mechanism of the leg was analyzed and the test procedure specified in Euro NCAP (New
  Car Assessment Programme) was simulated using large-scale nonlinear dynamic finite element program LS-DYNA 3D. The FE
  (Finite Element) model was validated by comparing CAE (Computer Aided Engineering) and test results. The influence of foam
  on the tibia acceleration, bending angle and shearing distance of the lower leg form was investigated by altering the x-direction
  thickness, density, and z-direction mounting position of the foam. The influence of parameters on the sum of axis forces and bending
  moment of the upper leg form was investigated by altering the bonnet lead edge (BLE) height, bumper lead, stiffness of hood and
  x-direction mounting position of upper radiator beam. The results indicate that the stiffness property of EPP foam is more beneficial
  for pedestrian protection among three types of foam (EPP, STRAND, PU). When the x-direction thickness, density, and z-direction
  mounting position of the foam are changed, the trend of the the tibia acceleration is complex without clear pattern, while the trend of
  the bending angle and shear distance are fairly constant and monotonic. The hood stiffness is less important to the upper leg injury,
  while the other factors have significant effects.

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  Structural design of SUV energy-absorbing based on#br# pedestrian leg protection

  YUE Guo-Hui, HAN Feng, LI Xi-Liang, MA Li-Jun, JIANG Bin-Qing, CHEN Xian-Ling, ZHANG Kai

  2010, 1(4):  307-321.  doi:10.3969/j.issn.1674-8484.2010.04.009

  Abstract ( 1833 )   PDF (2450KB) ( 1783 )  

  The conventional theory is not suitable for sports utility vehicle (SUV). A compatible project was designed for SUVs
  associating with design improvement items for pedestrian protection of several vehicles. The thicknesses and material parameters
  of the key components in energy-absorbing structures are highly sensitive to the injury criterion defined in pedestrian protection
  regulations. If associated analysies of deferent parts are not sufficient, thicknesses and materials can then hardly be more
  ideal for design projects. Nonlinear analysis was made for pedestrian protection energy-absorbing structures of vehicle models
  using design of experiment (DOE), with thickness of some structure strength parts changed and the analysis results compared.
  Correlation analysis with test results was also made. The results show that the expected design effects can be obtained.

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  Crash Performance Enabling Technologies, Structural Adheise#br# and Structrural Foam

  Kyle Royston, Martin Hornung, Micheal Hajj, Jingfen ZHANG

  2010, 1(4):  313-319.  doi:10.3969/j.issn.1674-8484.2010.04.010

  Abstract ( 2800 )   PDF (2092KB) ( 3168 )  

  A structural foam and a structural adhesive produced by Henkel Co. were introduced contributing to light weight
  construction and automotive safety for new energy automotive industry. Of these two new solutions, the chemical aspects,
  mechanical properties were measured for automotive application cases and the improvement contributions to vehicle
  performance. The results show that the structural foam has the excellent properties of being lightweight, providing both high
  strength and stiffness, therefore, offering many weight saving and cost reduction solutions, thus, increases the energy absorption
  capacity of the vehicle structure during collision situations; the structural adhesive provides an effective joint line, optimizing
  stress distribution, increasing structural strength and stiffness, preventing galvanic corrosion, and hence can also provide
  alternative cost reduction opportunities. These technologies were used by many OEMs (Original Equipment Manufacturer) on
  automotive production lines.

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  Modeling and analysis of the vehicle dynamic stability#br# coefficient for limit conditions

  HE Yuan-Chao, LI Liang, SONG Jian, LI Hong-Zhi, WU Kai-Hui

  2010, 1(4):  320-328.  doi:10.3969/j.issn.1674-8484.2010.04.011

  Abstract ( 1852 )   PDF (2460KB) ( 2485 )  

  Dynamics Stability Control (DSC) improves the vehicle stability. The selection of the nominal values of the yaw rate
  in the DSC control logic relates directly to the vehicle stability coefficient. In consideration of the characteristics of the vehicle
  with high slip and high lateral acceleration for limit conditions of dynamics stability control, analyzing the stability coefficient is
  needed to design the compositive stability coefficient as the key control parameter for the DSC controller. This paper contraposed
  a certain style of passenger car, using both the ADAMS dynamic simulation and real car test methods to analyze the steering
  characteristics with whole vehicle dynamic parameters to obtain the compositive stability coefficient. The limit condition of lane
  change test verifies the validity of the coefficient.

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  Automotive Safety

  Methods comparison of spotweld models in longitudinal beam#br# crash

  JIANG Xiao-Qing, YANG Ji-Kuang, XIAO Zhi, YE Ying-Tai, GUO Jie

  2010, 1(4):  327-331.  doi:10.3969/j.issn.1674-8484.2010.04.012

  Abstract ( 1901 )   PDF (1835KB) ( 2810 )  

   A corresponding crash finite element (FE) model was developed to study the influence of spotweld models in
  longitudinal beam crash and the simulation accuracy. The model uses the Ls-Dyna software with five types of spotweld models,
  including the rigid bar, spotweld, beam, spring, and solid element models, in the crash of a certain longitudinal beam jointed by
  spotwelds. With a real world test comparison, this paper analyzes the failure of spotweld, the deformation of longitudinal beam,
  the difficulty of modeling, and the advantages and disadvantages of modeling the connecting and loading. The results show that
  the failure of spotwelds affects the carsh simulation precision, and that the solid element model, deformable beam model and
  spring model have higher simulation precision.

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