COMPARISON VEHICLE AIRBAG LEVEL GROUND CONTROLLER TWO SPEEDS

COMPARISON VEHICLE AIRBAG LEVEL GROUND CONTROLLER TWO SPEEDS 3 D CSYS LS-DYNA SOFTWARE Velocity Scenarios 1. 1 m/s or 2. 2 m/s HOPSAN SOFTWARE UNITS m: kg: s: Pa: N: K

SCENARIO This scenario simulates a vehicle attached to a platform with an airbag under the platform. The vehicle and platform are dropped and have a velocity. When the platform impacts the RIGID ground the CONTROLLER(HOPSAN SOFTWARE) triggers to inflate the AIRBAG at a predefined value. The AIRBAG then controls the deceleration of the impact. LS-DYNA generates a FMU, this is installed into the HOPSAN with CONTROLLER logic based upon FOUR input parameters, acceleration of the platform legs. HOPSAN compares the integrated acceleration(i. e. velocity) parameters with a predefined value, set by the user, when exceeded, HOPSAN sends a returned value (i. e. load curve) to LS-DYNA to trigger the filling of the AIRBAG. LS-DYNA calculates the dynamics of the impacting payload during the whole simulation, before, during and after the filling of the AIRBAG.

PART ID AND MASSES NODES AND ELEMENTS

PART ID LOCATION 17 20 24 19 30 16 11 50 51 60 3 40 20 1

Dimensions

CO-SIMULATION BETWEEN LS-DYNA AND HOPSAN Velocity

Ls-DYNA FILE without co-simulation KEYWORDS 0_main_wofmu_9_03_k. k (Typical LS-DYNA file) LS-DYNA CASE FILE without model KEYWORDS 0_main_lsdyna_case_9_03_k. k (Typical LS-DYNA file With CO-SIMULATION KEYWORDS added)

HOPSAN MODEL NB. HOPSAN reads input parameters from LSDYNA simulation ‘acceleration’ HOPSAN integrates ‘acceleration’ parameters to ‘velocity’ HOPSAN checks these values in Greater Than Comparer module with the critical user defined value ’ 20. 0 velocity’ Logical And Operator checks that all FOUR velocities must be greater than 20. 0, if correct, CURVE 2 is modified, then sent to LSDYNA to trigger AIRBAG inflation

CASE=1

CASE=2

RUNTIMES VELOCITY SCENARIO 1. 1 m/s CASE=1 Generate the FMU CASE=2 Co-Simulation Between LS-DYNA and HOPSAN

Velocity Scenario 1. 1 m/s Velocity Scenario 2. 2 m/s

LS-DYNA RESULTS 1. 1 m/s LS-DYNA RESULTS 2. 2 m/s

Acceleration Signal from LS-DYNA CRITICAL VALUE=20. 0 Acceleration Signal from LS-DYNA Integrated Acceleration Signal from HOPSAN Load Curve 2 Modified when critical value reached HOPSAN RESULTS 1. 1 m/s T=20 ms Integrated Acceleration Signal from HOPSAN Load Curve 2 Modified when critical value reached CRITICAL VALUE=20. 0 T=13 ms HOPSAN RESULTS 2. 2 m/s

Kinetic Energy Airbag inflow dm/dt Contact Force Z displacement Airbag Pressure Contact Force Velocity Airbag Volume Z velocity LS-DYNA RESULTS