Study of mechanical properties and enhancing auxetic mechanism of composite auxetic structures

The auxetic structures attract much attention because of their good properties, such as enhanced energy absorption capacity and buckling resistance. It is an important topic to combine the auxetic structures with other materials or structures to improve their mechanical properties. In this paper, a composite auxetic structure was proposed, in which the embedded structure and re-entrant structure can deform independently to adjust the mechanical properties. Under uniaxial compression, the effects of changes in the embedded structure and re-entrant structure on Poisson's ratio, relative Young's modulus, and energy absorption of the composite auxetic structure were studied. By introducing the rate of change of mechanical properties, the effects of the embedded structure and re-entrant structure on the composite auxetic structure were studied. The results show that changing the embedded structure for Poisson's ratio and relative Young's modulus and changing the re-entrant structure for energy absorption can maximize the material utilization. And changing the re-entrant structure can make the mechanical properties of the composite auxetic structure reach a larger adjustable range. This study can provide a new way for the combination of future auxetic structures to meet the needs of different applications in civil engineering.