Mechanical behavior of beams with variable stiffness obtained by 3D printing

Abstract

Additive manufacturing or 3D printing gained a widespread popularity in recent years due to the ability of the method to manufacture components with high geometrical complexity. The most cost-effective process to manufacture plastic parts using 3D printing is the fused deposition modeling (FDM) method. Process parameters as the infill rates but also the printed pattern of different layers and their orientation have a significant influence on the mechanical properties of specimens fabricated by FDM. Controlling the process parameters is possible to generate materials with variable mechanical proprieties. The paper presents the analysis of a beam with constant cross-section but variable stiffness. Variable stiffness is achieved by changes in different cross-sections of the beam of the infill rates of the printing process. The mechanical behavior consisting of force-displacements curves is analyzed by three-point bending tests of variable stiffness samples and comparison with similar beams having constant infill rate. The results consist of E-modulus variation, maximum force and deflection curve. Analytical calculations and finite element analyses are employed to predict the mechanical behavior of the specimens printed with variable infill rate. The obtained results proved the concept of equal stress-beam with constant cross-section obtained by 3D printing process parameters variation.

Numerical Investigation of the Infill Rate upon Mechanical Proprieties of 3D-Printed Materials

“…Therefore, the influence of printing parameters may be used to customize the mechanical properties of the printed components. FDM technique has the potential to produce parts with locally controlled properties [ 10 , 11 , 12 , 13 ] by changing the deposition density (infill ratio) and orientation (infill pattern).…”

“…Strength, toughness, and geometric accuracy of the manufactured parts depend on various process parameters such as infill ratio, infill pattern, layer thickness, layer height and machine settings [ 14 , 15 , 16 , 17 , 18 ]. Using the optimum process-parameter settings can greatly improve the mechanical strength, surface quality and geometric accuracy by a considerable amount [ 10 , 15 , 19 , 20 , 21 , 22 ]. Modeling of parts by FDM technique implies also analytical models; some techniques being employed in the simulation models are presented in current work [ 23 , 24 ].…”