Design and mechanical performance analysis of re-entrant auxetic structures fabricated using SLA 3D printing: a comparative study

Auxetic structures, with a negative Poisson’s ratio, have gained significant attention for aerospace and automotive applications due to their superior mechanical performance. In this study, two different Auxetic Structures were used, namely Re–entrant Hexagon (A) and Re-entrant star triangular structure (B). They were designed and fabricated with the use of Stereolithography (SLA) Additive Manufacturing with the use of Standard Photopolymer Resin Material. The mechanical Behaviour was investigated with the help of compression testing according to ASTM D695 Standards using a Universal Testing Machine (UTM). These findings confirm that Auxetic geometry strongly influences mechanical behaviour and performance. The namely Re–entrant Hexagon (A) Geometry is better suited for Flexible and cushioning applications, such as biomedical devices used in implants, ergonomic materials, shoe soles, and soft protective paddings, while the Re- entrant Star triangular (B) geometry is suitable for applications requiring High Strength and Impact Resistance, such as aerospace Sandwich Structures, automotive crash absorbers, and protective equipment.