Article.pdf

J. S. Raminhos^a*, J. P. Borges^a, A. Velhinho^a

^*aCenimat (I3N)/Departamento de Ciências dos Materiais Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal

This work presents the application of 3-D printing technology to fabricate bi-dimensional lightweight composite meshes capable of simultaneously demonstrating auxetic properties (negative Poisson’s ratio (NPR)) and negative thermal expansion (NTE) behaviour, using polymers that do not exhibit NTE behaviour as constituent materials. To describe the combination of NPR and NTE characteristics, the designation of ‘anepectic’ was proposed. Different cases, obtained from varying either the material combination or the design parameters of the mesh, were tested to study the effects of the different combinations on the coefficient of thermal expansion (CTE). It was found that all meshes studied demonstrated a successful combination of NPR and NTE behaviours, and it was revealed that there is a possibility to tailor the meshes to activate the NTE behaviour within a chosen range of temperatures. For an extreme case, a Poisson’s ratio of −0.056, together with a CTE of −1568 ´ 10-6 C^-1 were observed.

This work was partially funded by FEDER funds through the COMPETE 2020 Program and National Funds through FCT - Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2013.