Quasi Static Compressive Behaviour of 3D Printed PLA and TPU Auxetic Cube Structures

Auxetic cellular structures, characterised by a negative Poisson’s ratio exhibit unique mechanical properties such as enhanced shear modulus, superior indenta-tion resistance, and remarkable energy absorption capabilities compared to con-ventional cellular materials. These attributes make them highly promising for ap-plications in crashworthiness, blast protection, and lightweight-multifunctional components. This study investigates the design, additive manufacturing, and crash performance of auxetic cellular structures fabricated with 3D printing using PLA and TPU materials. Parametric 3D auxetic cube model is developed in SolidWorks. 3D auxetic cube model is sliced into layer by using Bambu Studio slicing software before the digital fabrication starts. Specimens were fabricated using Fused Deposition Modelling 3D printing technology by using PLA and TPU filaments, and their dynamic crushing behaviours were analysed through experimental compression test results. Detailed deformation modes, stress-strain responses, plateau stress levels, and specific energy absorption were evaluated under different loading directions. The results demonstrate that auxetic structure effect significantly enhances the dynamic crushing strength and energy absorp-tion capacity of the PLA and TPU cubes. The findings highlight the strong de-pendency of crashworthiness characteristics on geometric design and provide de-sign guide lines for optimising auxetic structures for energy absorption applica-tions such as protective systems and lightweight structures. This work provides practical insight for the integration of topology optimization and additive manu-facturing in the development of high-performance crush resistant structures.