Numerical Analysis of Aluminum Foam for Impact Energy Absorption Purpose
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Date
2020-06
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Addis Ababa University
Abstract
Recently, there is a high interest to use lightweight aluminum foams for automotive, railway and
aerospace applications. Aluminum foam is usually used for energy absorption purpose for
crashworthiness application because of its high ductility and deformability. However, to keep the
safety and to avoid occupant injuries it is necessary to absorbed high impact energy generated
during collision. Therefore, to absorb high impact energy, the crash box material needs a special
material microstructure which is light in weight and can absorb more energy than the existing one
like CaCo3, SiC. B4C etc.
In particular, the analysis of energy absorption of aluminum foam in automotive for energy
absorption applications is limited. The main objective of this research is to model and analyze,
impact energy absorption of aluminum foam using the numerical approach. For this purpose, first,
fifteen aluminum foam CAD were developed by using Digimat multi-scale material modeling
software. Second, cubic elements with circular pore shape at 5%, 10% and 15% void percentage
and at 1.5mm, 2mm, 2.5mm, 3mm and 3.5mm pore sizes were modeled. Finally, the numerical
analysis of impact energy was carried out by using ANSYS workbench 19.2 Explicit dynamics by
applying initial low velocity was performed. The parameters such as pore size, voids percentage
and inclusion particles were compared to each other to optimize the proper percentage composition
and cell size for the best of energy absorption applications. The effects of pore size, foaming agent
and percentage composition on energy absorption were discussed. In addition the deflections,
reaction forces, accelerations, specific energy absorption, energy absorptions for all the models are
also determined with variable pore size and volume of porous, and it was compared with the effects
of agents on those variables.
Results showed that the Aluminum foam with 10% void fraction at bubbles (voids with air) size
of 2.5 mm exhibited better energy absorption and more stable was founded to be best candidate
material for impact energy absorbing device.
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Keywords
Aluminum foam, Voids, Energy absorption, Acceleration, Foaming agent, Reaction force, DIGIMAT, FEM analysis