An important assumption of conventional belt models is that the belt can slide over points that are fixed to bodies or the inertial space. Using finite elements sliding of the belt in all directions can be modelled. A study comparing both belt modelling techniques using the MADYMO program is described.
A mid-severity frontal impact sled test using a 50th percentile Hybrid III dummy is simulated. In addition, a performance study for oblique impact situations is presented to determine the effect of multi-directional belt slip of the shoulder belt. For the situations studied, it was found that both belt models can be used if belt roll-out at the shoulder does not occur. However CPU times are significantly higher for the simulations with finite element belts. An efficient approach for those cases where multi-directional belt slip of the shoulder belt occurs is to apply the finite element belt model only after a parameter study using the conventional belt model.