MECHCOMP7 - 7th International Conference on Mechanics of Composites, Porto, Portugal, 1 - 03 September 2021, vol.1, no.1, pp.18
structures have become more attractive materials, thanks to their high
strength, rigidity, and lightweight. In addition to being designable for the
desired working conditions and many advantages (easy to install and assembly,
being easily reparable etc.); due to the porous and hollow structure of the
core geometries forming the structure, they are also ideal materials for sound
and heat insulation, especially in structural applications. By the production
technologies developed in recent years, it has become possible to produce
structures with Negative Poisson's Ratio (NPR), known as "metamaterials."
These structures, also known as auxetic metamaterials, can exhibit unique
mechanical properties thanks to their NPR feature. Compared to conventional
materials, auxetic structures exhibit superior strength, better energy
absorption capability, higher impact resistance, and shear modulus. In this
study, two different sandwich structures (traditional hexagonal honeycomb and
re-entrant auxetic) were produced by 3D printers. One of the structures is
configured with a traditional feature and the other with NPR feature core
geometry. Acoustic performances were measured with
Acoustic Impedance Tube.
Furthermore, the Shock Loading behavior of the
sandwiches was carried out by using a shock tube test set up. Thus, both the acoustic performances and the
mechanical behavior of the structures under shock load have been studied
experimentally. For both loading cases, the effect of auxetic core was studied
and compared. Moreover, the results were discussed according to the wave speed.