Finite element study of effectiveness of modified front-end structure with aluminium foam in reducing pedestrian injury

Kongsakul, Wachirut; Carmai, Julaluk; Charoenthong, Sujeepapha

Affiliations

¹Faculty of Engineering, King Mongkut’s University of Technology North Bangkok, Thailand

²The Sirindhorn International Thai-German Graduate School of Engineering, King Mongkut’s University of Technology North Bangkok, Thailand

Abstract

Pedestrians are vulnerable road users. Unlike Occupant in cars, they do not have protection equipment and are often involved in serious accidents leading to fatalities. The reduction of pedestrian injuries has recently become one of the most important road traffic accident priorities. For the bonnet type of vehicle, leg and head injuries are the most prevalent type of injury associated with car-to-pedestrian collision. The possible reduction of leg and head injuries can be done through the design of vehicle bumper structure. Strong and stiff front structure of vehicle usually leads to severe injury to pedestrians in the accident. The use of new class of material like aluminium foam as part of bumper structure can provide better energy absorption capability and hence reduction of impact force to pedestrians. However, in order to design or modify the front structure to be safer for pedestrians, it is necessary to understand kinematics and injury mechanisms of car-pedestrian collisions, which are usually analyzed through costly full scale crash tests of a dummy or a cadaver. Finite element simulations with a human body model are an alternative mean, which offers information of post-crash kinematics and injury mechanisms. This paper has therefore employed the finite element model of pedestrian-city car collisions to study the effectiveness of the modified front-end bumper with aluminium foam in reducing the level of pedestrian injuries. The front bumper structure has preliminary been modified to include the aluminium foam as part of energy absorber. Two relative densities of aluminium foam were selected. The lower density one gave a better injury reduction performance. It was used to simulate a crash with THUMS to study detail injuries of pedestrian. The modified bumper model showed improved performance of injury reduction. The results exhibited the potential use of low density Al-foam in minimizing pedestrian injury and the benefit of using the human body finite element model which provides detailed injury information to help in the design and development of vehicle for pedestrian safety with cheaper cost compared to the actual full-scale crash tests.

Links

URL: http://www-esv.nhtsa.dot.gov/Proceedings/24/files/24ESV-000416.PDF

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