A correction factor to improve Poisson’s ratio prediction of 2D auxetic structure using finite element analysis and experiment

Auxetic structures as a part of lattice structures are designed with a negative Poisson’s ratio. The use of these structures is increasing due to their customized behavior in the aerospace and automotive industries. Several theoretical relations have been proposed to predict Poisson’s ratio of 2D auxetic structures. Most simple relations could not predict the Poisson’s ratio with a reasonable accuracy due to the absence of structure thickness. In this work, a numerical model based on finite element method is first validated by experimental results. In order to verify the numerical model accuracy, the constructed model is validated by experiment. Samples are printed, and the Poisson’s ratio is measured using the DIC method during the compression test. A correction factor based on the geometrical parameters of the structure, especially the structure thickness, is then introduced. This dimensionless correction factor not only consists of the minimum number of parameters but also significantly improves the theatrical model accuracy. The results showed that the theoretical relation error is cumulated by increasing the structural angle and thickness. The present correction factor is successfully reduced the error of theoretical relation from 800% to less than 2%.