Versatile Occupant Analysis Model (V.O.A.M) for Frontal Impacts Using LS-DYNA and MADYMO

Regulations implemented by safety commissions throughout the world have resulted in extensive physical testing to protect the occupants during frontal impact events. Significant prototype and test costs aimed at optimizing structure and restraint systems are associated with meeting these regulations. To help reduce development costs, Computer Aided Engineering (CAE) is often applied. LS-DYNA [1] coupled with MADYMO [2] is widely used in crash and occupant safety simulation. An analysis technique which utilized a single model to design and optimize interiors (instrument panel, seats, visor, steering wheel, steering column) and restraints (airbag, seatbelts, retractor, pre-tensioner) was developed. The single model concept captures the global structural kinematics through minimal vehicle representation. Global vehicle modes such as pitch and roll can be represented by applying prescribed motion boundary conditions extracted from full vehicle models. The following vehicle crash modes were investigated,

• NCAP [A] - 35mph flat frontal 50th% belted occupant
• 25mph 50th% unbelted and 25mph 5th% unbelted occupants FMVSS208 [B]
• 25mph 30 degree left and right angular 50th% unbelted occupant FMVSS208 [B]
• 30mph 5th% belted occupant FMVSS208 [B]
• 40mph 50^th% unbelted ODB [C]

This paper describes in detail the above methodology and its use in reducing computer, prototype and test costs.