Assessment of plastic deformation of the A356 foam sandwich panel during compression and bending tests

In present study closed cell aluminum A356 metal foam used as sandwich panel core with aluminum surface sheets. Then the uniaxial compressive plastic behavior and three-point bending behavior of foam slab and sandwich panel were studied. According to force-cross head displacement curves of compressive and three-point bending tests, the absorbed compressive and bending energy were calculated and by analyzing structure and metallography of cell walls, the deformation mechanism was estimated. Foam’s structure; in compressive test; showed same crushing behavior of cell walls for foam slabs and sandwich panels. However, sandwich panels showed two different behaviors due to core structure of foam in three-point bending test. First one was plastic hinges and U shape bending, around compression mandrel in three-point bending test and the other one was tearing of bottom face sheet of sandwich panel. Hence the absorption energy of sandwich panel and slab foams were calculated. The results show that sandwich panel and slab foam have almost same compressive strength. Also sandwich panel bending strength was 5.3 times greater than slab foam. However, absorbed energy in the longitudinal plastic deformation up to 7.38 % strain for slab foam was greater than sandwich panel. However, characteristic absorb energy during three-point bending test and according to disruption of panel structure mode showed that sandwich panel failure with plastic hinges had higher characteristic absorption energy.