Creep behavior of 3D printed polymer composites

The creep behavior of polymer composites containing different weight percentages of poly(lactic) acid (PLA), thermoplastic polyurethane (TPU), and poly(ethylene) glycol (PEG) is experimentally characterized and computationally modeled using finite element analysis (FEA). The composite filaments are manufactured with melt extrusion method by using twin-screw extruders, and then are employed in the 3D printing of creep samples. The samples are tested under a constant tensile load of 100 N. In this study, the computational model is developed by using the Generalized Voigt-Kelvin solid model and three terms in Prony series. The equations of Prony series were obtained by the Laplace transformation of Kelvin model. The experimental creep displacements and strains are compared with computational results, and a good agreement between them is observed. The maximum error percentage in computational result is approximately 6% as compared to the experimental result. Hence, it can be said that the relatively simple computational models developed are reliable and can be used to study the creep behavior of similar polymers. The error percentages can still be reduced by considering a higher number of terms of Prony series in the model. Highlights: Studied creep behavior for additively manufactured thermoplastic polymer composites. Developed computational model using three terms of relaxation modulus. The experimental results correlate very well with the computational model. Computational models can be used for other polymers.