Experimental and analytical investigation of 3D printed specimens reinforced by different forms of recyclates from wind turbine waste

Abstract

Waste from hundreds of thousands of tons of non-recyclable end-of-life wind turbine blades will be generated within the next decades. This work studies the effect of recycled fiber categories on the tensile properties of reinforced polylactic acid (PLA) specimens made by fused filament fabrication 3D printing. Three different fiber categories, that is, virgin, ground, and pyrolyzed, are examined and compared experimentally and analytically using micromechanical models. Tensile tests are performed on different PLA specimens prepared with the three fiber categories and two fiber contents of 5% and 10% per ASTM D638. Compared to virgin fibers, both recycled fibers, that is, ground and pyrolyzed fibers, exhibit higher strength and stiffness values. Ground recycled fibers showed higher ultimate tensile strength compared to the pyrolyzed ones, while higher stiffness values were obtained for pyrolyzed fibers. Single fiber tensile tests, pull-out interfacial strength tests, thermal analysis, and microscopic imaging are performed to evaluate parameters used in the micromechanical models. The Halpin-Tsai and Cox models showed good agreement with the experimental modulus results with errors less than 5% for pyrolyzed fibers, while the minimum prediction error was 24.1% for strength results.

Waste Management of Wind Turbine Blades: A Comprehensive Review on Available Recycling Technologies with A Focus on Overcoming Potential Environmental Hazards Caused by Microplastic Production

“…As with chemical recycling, discussed above, mechanical processing leads to a downgrading in the mechanical characteristics of the recovered materials (fiber and polymer), inducing a more significant strength degradation than the chemical route. Tahir et al [62] found that the tensile strength of recovered GF from grinding was up to 48% lower than that of virgin fiber. Powder residues (thermoset-resin-rich) cannot be reprocessed for new polymer products, but are usually implemented as fillers or reinforcements for cement, concrete, or other building materials [55].…”

Proposed holistic strategy for mechanical recycling of wind turbine blades for 3D printing and compression molding

“…The distinct project phases are defined and summarized below. Previous work and relevant results can be found in [22][23][24][25][26][27].…”

Unlocking the Potential of Wind Turbine Blade Recycling: Assessing Techniques and Metrics for Sustainability

“…Recent studies have shown that the recycled feedstock filament for FFF has superior tensile properties compared to that of pure polymer filaments, according to research by Rahimizadeh et al (2020) [59] and Tahir et al (2021) [63]. Rahimizadeh et al (2020) [59] revealed that ground fibres with a 20 mm gauge length had strength like virgin fibres.…”