Effect of different strut thickness on the mechanical behaviour of 3D printed auxetic structures

Abstract

In the recent era, the demand for structure design and materials that have mechanical properties to absorb high energy absorption and fracture resistance is growing exponentially. In order to meet the demand for intently designed structures, various structures have been designed and made. Among different design structures, auxetic design structures emerged as a flexible design that fulfilled the needs available in different application fields such as aerospace, defence, biomedical, structural, sponge mops, and many more. The main advantage of auxetic design structure is to show the property of negative Poisson’s ratios (NPR). The materials with NPRexhibit unusual and counterintuitive mechanical behaviour. It means the materials become flatter when stretched. This property allows them to exhibit exceptional mechanical characteristics that make them ideal for a wide range of applications. Further, fabrication techniques were also impacted by the mechanical performance of the auxetic structure. In the context of different fabrication techniques, 3D printing was found to be the most effective method to induce significant mechanical strength in the fabricated parts.Therefore, the present work focuses on the fabrication of auxetic structures using fused deposition modelling (FDM), and FDM is a kind of 3D (Three Dimensional) printing technique. Furthermore, experiments were performed with variations in strut wall thickness ranging from 0.4 to 1.2mm. In order to evaluate the mechanical performance of fabricated structures, compressive testing was performed on the Universal Testing Machine (UTM). In addition, the effect of different strut wall thicknesses on compressive mechanical behaviour was evaluated. The results showed that the maximum compressive strength, compressive Young’s modulus, compressive yield strength, energy absorption capacity, and plateau stress were found to increase with the increase in strut wall thickness.