Enhanced strength, toughness and reliability in crab exoskeleton–inspired 3D-printed porous thermoplastics

Abstract

Purpose

Fused deposition modeling enables multiscale structure control. However, most of this structural space is unexplored. Specifically, the impact of biomimetic porous structures on the mechanical behavior and reliability of common thermoplastics are unclear. In this work, porous structures inspired by the multifunctional crab exoskeleton were 3D-printed with different raster orientations, including fully rotating rasters similar to Bouligand structures found in biological materials. Tensile tests and simulations were performed to observe the stochastic behavior of fracture properties and to reveal the underlying origins of mechanical reliability in biomimetic porous systems.

Design/methodology/approach

Tensile tests were performed on 3D-printed porous structures with four different rasters. These rasters were biomimetic Bouligand, semi-Bouligand, 00 raster and 45°/−45° raster. In addition, two different sets were manufactured to observe the impact of contours on the mechanical behavior. A total of 137 tensile tests were performed. A total of 88 finite element simulations were executed using Abaqus built-in Hashin damage initiation criterion and energy-based damage evolution law. Weibull analyses were performed to quantify the stochastic properties.

Findings

Biomimetic Bouligand structure is effective in increasing fracture strength. Average fracture strength of the Bouligand structure was 33% higher compared to the default 45°/−45° and 10% higher compared to 00 rasters. Variations in strength were lower in Bouligand structure compared to the default 45°/−45° raster. However, 00 raster had the highest Weibull modulus m = 54 compared to Bouligand m = 25 and 45°/−45° m = 17. Simulations showed that Bouligand structure is effective in increasing the mechanical reliability through local damage accumulation around the holes. The simulated Weibull modulus of the Bouligand structure was 40 compared to the moduli of other rasters that ranged from 18 to 25.

Practical implications

The mechanical reliability of porous Bouligand structures is higher compared to other rasters, which makes the biomimetic structure a better choice for industrial applications. Contours decrease the strength and strain at failure for 3D-printed porous structures. Bouligand structures with rotating raster orientations increased strength and strain at failure when contours are present in the porous structure.

Originality/value

To the best of the authors’ knowledge, this is the first study showing the effects of biomimetic raster orientations on the mechanical behavior and the effects of contours on the tensile fracture properties of 3D-printed porous acrylonitrile butadiene styrene using tensile tests and fracture simulations. This is the first study applying composite fracture model to anisotropic porous 3D-printed polymers.

Citation

Keleş, Ö., Anderson, E.H., Tan, T.L., Wu, C.-L. and Karakoc, A. (2024), "Enhanced strength, toughness and reliability in crab exoskeleton–inspired 3D-printed porous thermoplastics", Rapid Prototyping Journal, Vol. 30 No. 9, pp. 1756-1768. https://doi.org/10.1108/RPJ-08-2023-0292