Evaluation of Advanced Gas Simulation Methodologies for Side Impact Airbags: A Comparative Study of CPG and CPM during the deployment interaction phase

Abstract

Side airbags are time-critical restraint systems in which gas flow, fabric deformation, and occupant contact strongly influence the predicted response. This thesis evaluates the recently introduced Continuum Particle Gas (CPG) method for side-airbag deployment simulations and compares it with the established Corpuscular Particle Method (CPM). The aim is to assess whether CPG improves the representation of side-airbag behaviour and occupant interaction during early deployment. The comparison was performed through an inflator tank test, a linear impactor setup, and simplified airbag–occupant interaction tests. Several Anthropomorphic Test Device configurations and arm positions were investigated. The methods were evaluated using airbag pressure response, unfolding behaviour, arm trajectory, selected occupant-related response quantities, and computational time. Physical test data and Volvo Cars reference models were used as comparison bases where available. The results show that both CPM and CPG capture the general pressure development and deployment response. However, CPG generally shows closer agreement with physical tests during early deployment, particularly regarding local airbag shape, crease formation, unfolding behaviour, and arm trajectory. CPG also shows improved agreement in several numerical occupant-related response metrics. During later pressure decay, CPM more often approaches the physical test pressure level, while CPG tends to remain slightly higher. The main limitation of CPG is its substantially higher computational cost compared with CPM. This indicates that it is currently more suitable as a complement to CPM rather than a direct replacement. This is especially relevant in cases where detailed early deployment behaviour and local gas-flow effects are important.