Investigation of the Effects of Loading Type/Direction and Geometric Size Parameters on 3D Auxetic Materials

Authors : Ersan Kırar

Pages : 409-424

Doi:10.55546/jmm.1797776

View : 55 | Download : 125

Publication Date : 2025-12-26

Article Type : Research Paper

Abstract :Auxetic materials with a negative Poisson\\\'s ratio expand transversely under tensile loading and contract transversely under compressive loading. This deformation behavior makes them preferred in many applications. Limited studies on 3D auxetic materials have been encountered in the literature. Furthermore, since no studies have been found examining the effects of geometric size (±25%) and the effects of loading type (in-plane/out-of-plane)/direction (tension/compression) on auxetic materials, these parameters were investigated in three different 3D auxetic structures (re-entrant, modified re-entrant, and star) using the finite element method (FEM). As a result of the study, the effects of the investigated parameters on auxetic and mechanical properties were examined using the parameters of transverse/longitudinal deformation, equivalent stress, and Poisson\\\'s ratio. The obtained data indicate a decrease in equivalent stress and deformation with increasing size, while a 2% change in the Poisson\\\'s ratio was obtained. Although the equivalent stress in auxetic structures increases with decreasing size, better auxetic properties are obtained due to the increase in the Poisson ratio. It was determined that the effect of the loading direction in auxetic structures was below 1% and the type of loading in auxetic structures depends on the geometric structure of the auxetic structure. Moreover, the design with the best auxetic properties was found to be the R-coded design in the in-plane direction, while the S-coded design was found to be the the best out-of-plane loading.
Keywords : 3D Ökzetik malzeme, Sonlu elemanlar yöntemi, Ölçü etkisi, Yükleme türü/yönü

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