Chest Deflection mapping between HBM Connect® 50M and Humanetics ATD models for frontal impact

Objective Human Body Models (HBMs) are increasingly recognized by consumer protection agencies as essential tools for evaluating vehicle safety, complementing the use of traditional Anthropomorphic Test Devices (ATDs). However, HBMs are new for product development and pose challenges in connecting them with the ATDs. These challenges can be overcome if a link is established for the injury metrics between HBMs and ATDs. The study aims to develop a chest deflection mapping function between the HBM Connect® 50M (HBMC-50M) and two ATD models: THOR-50M and Hybrid III 50M for thoracic assessment in frontal impact. Method Several frontal chest loading scenarios were selected from the HBM4VT qualification catalogue (Euro NCAP technical bulletin CP 550), including hub impacts and table-top tests. Matched-pair LS-DYNA simulations were conducted with HBMC-50M and the ATD models recording peak chest deflections for developing the mapping function. In the HBMC-50M model, deflection outputs were defined— analogous to the four IR-TRACCs in THOR-50M, and one for sternum potentiometer in Hybrid III 50M. Two linear regression models were developed: one mapping chest deflections between HBMC-50M and THOR-50M, and the other between HBMC-50M and Hybrid III 50M. Results and Discussion The mapping suggests that a 30 mm chest deflection in THOR-50M and Hybrid III 50M corresponds to approximately 37 mm and 65 mm, in HBMC-50M suggesting that HBMs are softer and more compliant than ATDs for the torso region. Data points were selected to ensure a coefficient of determination (R²) greater than 0.6. Future work will include additional sled cases to further validate and improve these mappings for frontal impact load case applications. Conclusion This study establishes chest deflection mapping functions to facilitate the interpretation of HBM-C 50M outputs using established ATD-based chest deflection metrics. A strong correlation is observed with THOR-50M, and a moderate correlation is observed with Hybrid III 50M.