Geometric effects on micropolar elastic honeycomb structure with negative Poisson's ratio using the finite element method

A two-dimensional triangular finite element formulation including an extra degree of freedom was derived on the basis of Eringen's micropolar elasticity theory. The linear triangular element and a corresponding computer program were developed to investigate the relation between the Poisson's ratio of re-entrant honeycomb structure using various structural geometric parameters. According to our numerical results, the honeycomb structure can exhibit a negative Poisson's ratio with the appropriate re-entrant angle. We also found that the Poisson's ratio values varied when changing the honeycomb structure cell rib length and width.