Investigation of impact behavior rubber reinforced composites with curved surfaces

The aim of this study is to produce sandwich composites with curved surface geometries by adding EPDM (Ethylene Propylene Diene Monomer) rubber interlayers between glass fiber woven fabrics and to investigate their behavior under the effect of low velocity impact numerically and experimentally.For this purpose, glass fiber and rubber layers were added to steel molds manufactured in curved forms and sandwich plates were produced through the vacuum infusion method. Low-velocity impact tests were performed by lowering strikers with a hemispherical tip on the produced curved-surface plates, and the effect of the surface geometry on the impact absorption energy was researched. With the use of rubber interlayers, the energy absorption feature of the composites has been increased by a maximum of 45%. Furhermore, 1.5 times width increase of the sheet of curved-surface composites increased the absorption energy by 16%, while a height increase of 2.3 times decreased the absorption energy by 13%. With the use of rubber layers on the outer surface of the composites, a maximum 14% reduction in the damage area was observed. In the numerical part, the tests performed were modeled using the LS-DYNA finite element package program and the Hashin damage criterion-based MAT162 material model was used in order to see the damage caused to the composite structure in three dimensions after the tests. Numerical results were obtained in agreement with the experimental data in terms of energy absorbed at a minimum of 82%.