Using numerical-experimental analysis to evaluate rPET mechanical behavior under compressive stresses and MEX additive manufacturing for new sustainable designs

Abstract

Purpose: Because of the anisotropy of the process and the variability in the quality of printed parts, finite element analysis is not directly applicable to recycled materials manufactured using fused filament fabrication. This study investigates the numerical-experimental mechanical behavior modeling of the recycled polymer rPET manufactured by MEX (Material Extrusion) process under compressive stresses for new sustainable designs. Design/Methodology: Forty-two test specimens were manufactured and analyzed according to the ASTM D695-15 standards. Eight numerical analyzes were performed on a real design manufactured with rPET using Young's compression modulus from the experimental tests. Finally, eight additional experimental tests under uniaxial compression loads were performed on the real sustainable design for validating its mechanical behavior versus computational numerical tests. Findings: As a result of the experimental tests, rPET behaves linearly until it reaches the elastic limit, along each manufacturing axis. The results confirmed the design's structural safety by the load scenario and operating boundary conditions. Experimental and numerical results show a difference of 0.001 mm to 0.024 mm, allowing for the rPET to be configured as isotropic in numerical simulation software without having to modify its material modeling equations. Practical implications: The results obtained are of great help to industry, designers, and researchers because they validate the use of recycled rPET for the ecological production of real-sustainable products using MEX technology under compressive stress and its configuration for numerical simulations. Major design companies are now using recycled plastic materials in their high-end designs. Originality: Validation results have been presented on test specimens and real ítems, comparing experimental material configuration values with numerical results. Specifically, no industrial or scientific work has been conducted with rPET subjected to uniaxial compression loads for characterizing experimentally and numerically the material using these results for validating a real case of a sustainable industrial product