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cross section crash boxes

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CHAPTER 7<br />

MODELING RESULTS OF FOAM, EMPTY AND AL<br />

FOAM FILLED CRASH BOX<br />

7.1. Simulation Results of Al Foam Modeling<br />

The simulation stress-strain curves of honeycomb material model (Mat26) and<br />

Desphande and Fleck Foam model (Mat154) are shown in Figure 7.1 together with the<br />

experimental stress-strain curves of 0.11 and 0.15 relative dense Alulight Al foams.<br />

Both material models stress-strain curves show good agreements with the experimental<br />

stress-strain curves, proving that both material cards are capable of simulating the<br />

deformation of partially filled <strong>crash</strong> <strong>boxes</strong>. Because of its simplicity of the<br />

implementation, Mat 26 Honeycomb material card is selected for the simulations of<br />

filled <strong>crash</strong> <strong>boxes</strong>. The Deshpande and Fleck analytical foam model parameters<br />

determined in Chapter 6 are used to construct the stress-strain curves of Alulight foams<br />

at various densities. For comparison, the experimental and Mat 26 simulation<br />

compression stress-strain curves of Alulight foams at various relative densities are<br />

shown together in Figure 7.2. The experimental foam stress-strain curves at varying<br />

relative densities shown in the same figure are well matched with the simulated stress-<br />

strain curves. This further proves the capability of the analytic model developed in<br />

predicting correct material stress-strain data for the simulations.<br />

132

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