The Influence of Pelvic-belt Angle on Wheelchair Occupant Injury Risk: a simulation study

The angle of the pelvic-belt connection to the vehicle floor is an important consideration, but this has not been previously evaluated for wheelchair users. This paper reports on the use of MADYMO multibody modelling to evaluate the influence of pelvic-belt angle on pelvic-belt forces and wheelchair occupant kinematics and loading in a standardized frontal impact. A model of the 50th percentile male Hybrid III dummy seated in a manual wheelchair and subjected to a 20g frontal impact pulse was used as the baseline. Results show the horizontal component of the pelvic-belt contact force with the abdomen/pelvis remains broadly constant as the pelvic-belt angle increased from 30 to 75, but there was an almost threefold increase in the vertical component of the pelvic-belt contact force. The abdomen loading from the pelvic-belt decreased dramatically for belt angles in excess of about 45. The shoulder-belt force increased with increasing pelvic-belt angle. These results indicate that a pelvic-belt angle in excess of about 45 is necessary to prevent significant abdominal loading, but pelvic-belt angles above 60 result in unnecessary increased occupant loading.