Mechanical characterization of functionally graded materials produced by the fused filament fabrication process

Abstract

Abstract In this research study, the design and fabrication workflow of functionally graded materials (FGMs) were introduced using fused filament fabrication (FFF) process. Rigid polymers were mechanically characterized in three printing directions. Tensile strength and modulus of elasticity values for YZ and XY printing orientation specimens indicated similar results. Printing in the XZ direction showed poor strength values in comparison with other printing directions. Interface analysis with different transition patterns was accomplished and the advantage of gradient transition was achieved. Micrography of specimens was analyzed to investigate the internal structure and was used to validate the test results. Statistical methods were applied to investigate the relationship between microstructural descriptors (volume fractions) and process-related parameters (printing temperatures). The results of the analysis of variance (ANOVA) have confirmed that printing temperature and concentration have a significant impact on tensile test results. The data-driven approach was employed to construct a linear regression models in order to formulate input data for finite element analysis (FEA). As a result of FEA simulation, effective Young’s modulus was calculated using a MATLAB code. FEA-predicted Young’s moduli were validated through experimental test results. The comparison of the numerical method and experimental values showed less than 5% error for FGM specimens printed in 250, 260 and 270 °C temperatures. FFF process with FGM could have potential applications in medical, structural, and automotive industries by locally varying material properties. This study presents a unique method of fabricating FGM structures with low-cost manufacturing process.