Development of a finite element dummy model for improved lying-occupant safety evaluation

Abstract

The aim of this study was to develop an FE crash test dummy model to be used for safety evaluation of lying truck-occupants. The model was to be included in an available model of a truck sleeper section for simulations of a truck frontal impact using the Radioss finite element solver. The work began with a literature study in order to find out which kind of occupant model would be useful for the purpose. An available FE model of the US SID, a crash test dummy used as an occupant substitute in car side impact testing, was chosen to be a platform for further development and adjustment to supine posture, i.e. lying position. The choice was motivated by the resemblance in load cases experienced by a passenger lying in the bunk of a truck during frontal impact and a seated passenger in car side impact, both being impacted laterally. The primary adaptation of the dummy included development of a new, straight hip part and adjustment of the lower-limb joint properties. The simulations made implied a need for further tuning of the dummy model in order to make it work properly for the loading case in question. Comparisons have been made between the FE simulations and physical sled tests, having similar configuration, except for the occupant substitute used. For the physical tests a pedestrian Hybrid III dummy was used, designed primarily for frontal impact and therefore having different lateral responses. The main difference is the thorax region of the dummies, where the Hybrid III is significantly stiffer than the US SID, which in its turn is supposed to be stiffer than a human. The work resulted in a well validated finite element dummy model, named Sleepy, having the unique characteristics of supine posture, sensitivity to lateral loads, capability of measuring side impact injury criteria and being useable for pedestrian simulation in a truck-to-pedestrian impact.