Evaluation of a dummy design by using a human body model

Human body models for occupant protection became popular in the last years. They started to turn from high sophisticated research tools to reasonably applicable tools to support some specific areas of occupant safety. This study is focused on the evaluation of the BioRID-II shoulder design by using the THUMS human body model. After the introduction of the BioRID-II into several test protocols to assess whiplash associated disorder, some serious concerns about the dummy’s performance emerged. Various simulations and tests indicated that the dummy’s shoulder design may cause unrealistic loads. Simulation runs with the THUMS in the same test environment were used to verify this assumption. The overall kinematics and therefore the accelerations of human body model and dummy model correlate well. A comparison of forces and moments between both is difficult because of the completely different internal structure of human and dummy. However, in-depth analyses showed that the simple dummy shoulder causes direct neck loads, while a human shoulder distributes the load through clavicles and scapulas to the whole rib cage. The same artefact was observed at the recently developed model of a female rear impact dummy (EvaRID) that is based on the BioRID-II design. The THUMS was scaled down to the size of the EvaRID by keeping almost same relative differences in size as observed between BioRID-II and THUMS. The dummy artefact could be verified with the downscaled THUMS, too. In summary, a human body model is a complex, not easy to handle but helpful tool to evaluate the performance of crash test dummies and to identify dummy related artefacts. While the overall kinematics between dummy and human model are somehow comparable, forces and moments may differ because of the different internal designs of dummy and human body model.