International harmonisation of side impact standards: vehicle design and thoracic injury criteria trends

Abstract

This paper presents a computational study of the effects of three vehicle parameters on the resulting thoracic injury criteria in side impacts. The parameters evaluated are: door velocity-time (V-t) profile; the effective modulus of the door interior; and initial door-to-occupant offset. Regardless of door modulus, initial offset, or the criterion used to assess injury, higher peak door velocity is shown to correspond with more severe injury. Injury outcome is not, however, found to be sensitive to the door velocity at the time of occupant contact. A larger initial offset generally is found to result in lower injury, even when the larger offset results in a higher door velocity at occupant contact, because the increased offset results in contact later in the door V-t profile - closer to the point at which the door velocity begins to decrease. Cases of contradictory injury criteria trends are identified, particularly in response to changes in the door modulus. Maximum chest deflection and maximum viscous criterion gradually decrease as the door modulus increases. TTI, however, increases with some increases in door modulus. Complex interactions between the three parameters are observed, and their interpretation is shown to depend on the specific injury criterion analysed.