Development of a hybrid material with auxetic phase

Abstract

Hybrid multiphase materials exhibit a wide range of desirable properties, which may be tailored to the needs of their user or application. Modern solutions often use advanced smart materials with specific properties, which in some cases allow the development of devices previously impossible to manufacture due to restrictions of conventional materials. There is ongoing research on multiphase materials composed of phases with differing Poisson’s ratios, which have increased elastic modulus compared to their respective monophase components. Precise analysis of multiphase materials composed of periodic microstructures is possible with the use of multiscale modeling methods and numerical homogenization of individual phases’ geometric structures into homogenous materials retaining the properties of their representative volume elements. Auxetic materials behavior under loading differs from conventional materials. Their Poisson’s ratio value is negative, which means that when they are uniaxially stretched they both elongate and expand laterally, and while uniaxially compressed they both shorten and shrink laterally. While seemingly changing volume, their density remains constant in microscale. Deformation causes the gaps in auxetics patterned structure to change shape and size, but the actual material of the structure remains unchanged. This paper presents the results of development of a multiphase hybrid material with auxetic phase, in two variants. First, with the goal of maximization of the material’s elastic modulus. Second, to obtain a zero-value effective Poisson’s ratio. Different patterns of phases distribution in the material were analyzed. A few different auxetic structures were taken into consideration. Optimization utilized numerical simulation based on finite element method.