Effect of 3D printing parameters on the thermomechanical behavior of TPU 90A

Abstract

This work investigates the thermomechanical and shape memory behavior of TPU 90A in both raw filament form and after 3D printing by fused deposition modeling (FDM). The study systematically explores how key printing parameters such as extrusion temperature, infill density, and infill direction affect material performance. A major contribution of this research is the development of a UMAT subroutine in Abaqus, enabling accurate simulation of TPU 90A’s thermomechanical and shape memory responses under varied loads and temperature conditions. Validation with experimental data demonstrates a strong shape memory effect, with shape fixity ratio (Rf) and recovery ratio (Rr) exceeding 98%. The numerical model achieves excellent agreement with experiments, as the simulated Young’s modulus (53.97 MPa) closely matches the measured value (55.38 MPa). Optimal mechanical properties were obtained using an extrusion temperature of 230 °C, 45° infill orientation, and 100% infill density, effectively balancing strength and efficiency. Practical feasibility was illustrated through the fabrication of a personalized finger orthosis. Stress analysis revealed peak values of 17.76 MPa, confirming adequate rigidity for stabilization in medical applications.