Title: Re-entrant auxetic cellular structures fabricated by material extrusion technique: an investigation on mechanical properties under shear loading

Authors: Swapnil S. Vyavahare; Soham K. Teraiya; Shailendra Kumar

Addresses: Department of Mechanical Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, India ' Department of Mechanical Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, India ' Department of Mechanical Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, India

Abstract: Re-entrant auxetic cellular (REC) structures are recently employed in various automotive, aerospace, biomedical and sports applications. For fabrication of these structures with good mechanical strength, material extrusion (ME) technique is most economical additive manufacturing technique. Mechanical properties of ME fabricated parts majorly depend upon process parameters. The present paper describes an experimental study of influence of process parameters under shear loading for ME fabricated REC structures. Structures of acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA) materials are fabricated. Three process parameters of ME namely layer thickness, raster width, and build orientation are considered to investigate their influence on responses namely strength, stiffness, and specific energy absorption (SEA) under shear loading. Experiments results are analysed using analysis of variance (ANOVA). It is observed that all parameters along with their interaction significantly influence all responses. In ABS structures, shear strength initially decreases and then increases with increase in layer thickness; while for PLA structures exact reverse trend is observed. Based on the analysis of experimental results, regression models are developed. Also, optimal configurations of the specimens are determined to maximise responses using desirability function.

Keywords: re-entrant auxetic cellular structures; mechanical properties; material extrusion technique; process parameters; shear.

DOI: 10.1504/IJMATEI.2023.136116

International Journal of Materials Engineering Innovation, 2023 Vol.14 No.4, pp.344 - 364

Received: 25 Apr 2022
Accepted: 08 Aug 2022
Published online: 17 Jan 2024 *

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