Pedestrian Collision Responses Using Legform Impactor Subsystem and Full-Sized Pedestrian Model on Different Workbenches

2018 ◽  
Author(s):  
Obaidur Rahman Mohammed ◽  
Shabbir Memon ◽  
Hamid M. Lankarani
Keyword(s):  
Fe Model ◽  
Finite Model ◽  
Lower Extremity Injuries ◽  
Full Size ◽  
Pedestrian Impact ◽  
Extremity Injuries ◽  
Multi Body ◽  
Impact Simulations ◽  
The Impact ◽  
Pedestrian Collisions

Car-pedestrian collision fatalities have been reported for a significant number of roadside accidents around the world. In order to reduce the lower extremity injuries in car-pedestrian collisions, it is important to determine the impact forces on the pedestrian and conditions that the car frontal side impacts on the lower extremities of the pedestrian. The Working Group 17 (WG17) of the European Enhanced Vehicle-safety Committee (EEVC) has developed a legform subsystem impactor and procedure for assessing pedestrian collisions and potential injuries. This research describes a methodology for the evaluation of the legform impactor kinematics after a collision utilizing finite element (FE) models of the legform and cars and comparing the simulation results with the ones from a multi-body legform model as well as a 50th percentile male human pedestrian model responses. Two approaches are carried out in the process. First, the collision strike simulations with the FE model using an FE lower legform is considered and validated against the EVVC/WG17 regulation criteria. Secondly, the collision strike simulations with a multi-body legform and an ellipsoidal multi-body car model are conducted to compare the responses from the FE model and the multi-body model. The results from the impact simulations of FE legform and the multi-body legform are also compared with the ones from a full-size pedestrian model at constant speeds. All the models and simulation in this are using the LS-DYNA nonlinear FE code, while the multibody legform, car, and full-sized pedestrian models are developed and evaluated in MADYMO. The results from this study demonstrate the differences between the subsystem legform and the full-size pedestrian responses as well as suitability of various FE and multibody models related to pedestrian impact responses. Different workbenches comparisons with finite model and ellipsoidal models gives more better correlation to this research.

scholarly journals A Description of Shock Attenuation for Children Running

2010 ◽  
Vol 45 (3) ◽  
pp. 259-264 ◽  
Author(s):  
John A. Mercer ◽  
Janet S. Dufek ◽  
Brent C. Mangus ◽  
Mack D. Rubley ◽  
Kunal Bhanot ◽  
...  
Keyword(s):  
Shock Attenuation ◽  
Organized Sport ◽  
Lower Extremity Injuries ◽  
Number Of Children ◽  
Dependent Variables ◽  
Sport Activities ◽  
Impact Acceleration ◽  
Extremity Injuries ◽  
The Impact ◽  
Attenuation Characteristics

Abstract Context: A growing number of children are participating in organized sport activities, resulting in a concomitant increase in lower extremity injuries. Little is known about the impact generated when children are running or how this impact is attenuated in child runners. Objective: To describe shock attenuation characteristics for children running at different speeds on a treadmill and at a single speed over ground. Design: Prospective cohort study. Setting: Biomechanics laboratory. Patients or Other Participants: Eleven boys (age  =  10.5 ± 0.9 years, height  =  143.7 ± 8.3 cm, mass  =  39.4 ± 10.9 kg) and 7 girls (age  =  9.9 ± 1.1 years, height  =  136.2 ± 7.7 cm, mass  =  35.1 ± 9.6 kg) participated. Intervention(s): Participants completed 4 running conditions, including 3 treadmill (TM) running speeds (preferred, fast [0.5 m/s more than preferred], and slow [0.5 m/s less than preferred]) and 1 overground (OG) running speed. Main Outcome Measure(s): We measured leg peak impact acceleration (LgPk), head peak impact acceleration (HdPk), and shock attenuation (ratio of LgPk to HdPk). Results: Shock attenuation (F2,16  =  4.80, P  =  .01) was influenced by the interaction of speed and sex. Shock attenuation increased across speeds (slow, preferred, fast) for boys (P < .05) but not for girls (P > .05). Both LgPk (F1,16  =  5.04, P  =  .04) and HdPk (F1,16  =  6.04, P  =  .03) were different across speeds, and both were greater for girls than for boys. None of the dependent variables were influenced by the interaction of setting (TM, OG) and sex (P ≥ .05). Shock attenuation (F1,16  =  33.51, P < .001) and LgPk (F1,16  =  31.54, P < .001) were different between TM and OG, and each was greater when running OG than on the TM, regardless of sex. Conclusions: Shock attenuation was between 66% and 76% for children running under a variety of conditions. Girls had greater peak impact accelerations at the leg and head levels than boys but achieved similar shock attenuation. We do not know how these shock attenuation characteristics are related to overuse injuries.

Further Validation of the Ford Human Body FE Model and Use of the Model to Investigate the Effects of Shoulder Belt Force Limiting of 3-Point and 4-Point Restraints in Frontal Impact

2008 ◽  
Author(s):  
Raed E. El-Jawahri ◽  
Jesse S. Ruan ◽  
Stephen W. Rouhana ◽  
Saeed D. Barbat ◽  
Priya Prasad
Keyword(s):  
Human Body ◽  
Ford Motor Company ◽  
Steering Wheel ◽  
Point System ◽  
Fe Model ◽  
Frontal Impact ◽  
Frontal Impacts ◽  
Vehicle Structure ◽  
Impact Simulations ◽  
The Impact

Ford Motor Company human body FE model was validated against 3-point & 4-point belted PMHS tests in frontal impact and PMHS knee impact. The chest deflection, chest acceleration, and belt force in frontal impact simulations were compared with the PMHS test data, while the impact force, femur acceleration, pelvis acceleration, and sacrum acceleration of the knee impact simulations were compared with the respective corridors from PMHS tests. The model used represents a 50th percentile adult male. It was used to study the effects of shoulder belt force limit on 3-point and 4-point restrained occupants in frontal impacts without airbags. A 25 g pulse and a shoulder belt load limit of 1, 2, 3, 4, 6, and 8 kN were used for the 3-point and 4-point restraint systems with a rigid steering wheel, front header, and windshield of a stiffer larger vehicle structure. The results showed that the head acceleration and the chest deflection of the 4-point belt system are less than the respective cases of the 3-point system while the chest acceleration levels were about the same in 3-point and 4-point belt. The mid-shaft femur forces were always higher in the 4-point belt than those of the 3-point belt.

DEVELOPMENT OF A FRANGIBLE DESIGN OF SMALL FIXED-WING UNMANNED AERIAL SYSTEM

2021 ◽  
Author(s):  
ANURAG ◽  
KALYAN RAJ KOTA ◽  
THOMAS E. LACY
Keyword(s):  
Unmanned Aircraft ◽  
Fe Model ◽  
Initial Stage ◽  
Internal Structures ◽  
Significant Damage ◽  
Target Frame ◽  
Energy Absorbing ◽  
Impact Simulations ◽  
The Impact ◽  
Collision Trajectory

Existing studies show that small fixed-wing unmanned aircraft systems’ (FWUASs) mid-air collisions with aircraft can cause substantial damage. Upon a 250 knots impact, a ~1.8 kg “tractor” configuration of FW-UAS can perforate aircraft skin, thereby damaging the internal structures such as ribs, frames, etc., posing severe threat to manned air fleet. Significant damage is primarily caused by FW-UAS’s heavy and rigid components such as motor, battery, and payload especially due to their roughly in-line arrangement and proximity with one another. In this work, a modified FW-UAS finite element (FE) model was developed that included a “pusher” engine (i.e., motor in the aft of the forward fuselage) configuration to reduce the impact severity during airborne collisions. A polymeric foam nosecone was attached to the front of the FW-UAS FE model to dissipate impact energy. To assess its energy absorbing capacity, a comparative study with expanded polypropylene (EPP), polyurethane (PUR), and polystyrene (IMPAXX700) foams was performed. Conical and semi-spherical nosecone configurations were studied as part of this research. A series of LS-Dyna impact simulations were performed with the pusher configuration of FW-UAS impacting a 1.59 mm thick aluminum 2024-T3 flat plate sandwiched between a rigid target frame. In addition, a frangible design of the FW-UAS, in which the payload is diverged from the in-line collision trajectory of battery and motor upon impact, was implemented and assessed. Force generated during the initial stage of impact is leveraged through lightweight and friable structural links to diverge the payload to avoid impact along the single axis as of the battery and motor. Damage severity is evaluated through target plate tear, and velocity of payload during impact, it being the major damage causing component.

scholarly journals The Impact of the Helmet-Lowering Rule on Regular Season NFL Injuries

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0040
Author(s):  
Erik Stapleton ◽  
Randy Cohn ◽  
Colin Burgess
Keyword(s):  
Relative Risk ◽  
Lower Extremity ◽  
Risk Reduction ◽  
Injury Risk ◽  
National Football League ◽  
Head Injuries ◽  
Lower Extremity Injuries ◽  
Extremity Injuries ◽  
The Impact ◽  
Rule Implementation

Objectives: The National Football League (NFL) has been under growing scrutiny from the public due to the apparent rise in concussions and head injuries and the subsequent deleterious effects. In efforts to address these concerns, the NFL implemented a new “Helmet-lowering” rule prior to the 2018-2019 season. This rule is defined as “a foul if a player lowers his head to initiate and make contact with his helmet against an opponent.” The purpose of this paper was to compare incidence of injuries in NFL players prior to and after implementation of this new rule. Methods: NFL injury data was retrospectively reviewed from public league records for all players in regular season games played from the 2017 and 2018 NFL seasons. An injury was defined as any player listed on a team’s injury report that was not previously documented on the team’s report one week preceding the index injury. Injury rates were reported as the number of injuries per 1000 athletic exposures (AE’s). Athletic exposures were defined as equal to the sum of the total number of NFL regular-season games played. Relative risk (with 95% CI) was calculated by using the number of injuries per 1000 athletic exposures for the season before and after the new rule implementation. Risk reduction was then calculated for the overall injuries, upper/lower extremity and head injuries. Results: Over the 2 seasons there were a total of 2,774 injuries identified. After rule implementation at the beginning of the 2018 season, there was an overall relative risk (RR) of 0.91 for injury (95% CI 0.88 to 0.95, p<0.0001), with an injury risk reduction of 8.73%. Upper extremity injuries had a RR of 0.76 (95% CI 0.65 to 0.87, p=0.0005) and a risk reduction of 24.10%. Lower extremity injuries had a RR of 0.91 (95% CI 0.87 to 0.96, p=0.0005) with a risk reduction of 8.63%. In concussions and head injuries there was an overall RR of 0.55 for injury (95% CI 0.44 to 0.69, p<0.0001), with an injury risk reduction of 45.10%. Wide receivers and linebackers were most commonly injured players on offense and defense, respectively. Conclusion: Implementation of the new Helmet-Lowering rule seems to have played a role in significantly decreasing the NFL athlete’s risk of injury across all measures, most notably in concussion and head injuries.

PERSONALIZED CUSTOMIZATION METHOD OF HYBRID HUMAN MODEL FOR PEDESTRIAN-VEHICLE ACCIDENT RECONSTRUCTION

2021 ◽  
Vol 21 (02) ◽  
pp. 2150009
Author(s):  
SHA XU ◽  
XIANLONG JIN ◽  
CHUANG QIN ◽  
XIANGHAI CHAI
Keyword(s):  
Traffic Accidents ◽  
Human Model ◽  
Accident Reconstruction ◽  
Fe Model ◽  
Impact Simulation ◽  
Whole Process ◽  
Vehicle Accident ◽  
Pedestrian Traffic ◽  
Multi Body ◽  
The Impact

Traffic accident reconstruction is a reverse dynamic problem, which requires hundreds of iterations to reconstruct the whole process of accident. However, in current pedestrian-vehicle accident reconstructions, it is difficult to quickly establish a pedestrian model based on specific cases, and it is hard to solve the contradiction between calculation accuracy and calculation time. In this paper, a personalized pedestrian customization method is proposed. First, the pedestrian structure is divided into independent modules according to obvious bony markers. For each independent module, multi-body (MB) model and finite element (FE) model are established, respectively. Then the appropriate modules are selected to form the whole hybrid pedestrian model. This method can customize the structure of pedestrian model according to the injury characteristics of pedestrians in specific accidents, and customize the parameters of pedestrian model according to the height and weight of pedestrians. The impact simulation tests are carried out on hybrid pedestrian models to verify the reliability of the models. The proposed method can effectively improve the modeling efficiency of pedestrian models and the reconstruction quality of pedestrian traffic accidents.

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