ARTÍCULO

Analysis and numerical simulation of the mechanical performance of FDM samples with variable infill values

Cerda Avila, Steffany Noemí Medellín Castillo, Hugo Iván de Lange, Dirk Frederik
Journal of Engineering Materials and Technology, Vol. 141, pp. 1-7., 2019.

ABSTRACT:

The use additive manufacturing (AM) technologies, also known as Rapid Prototyping (RP) technologies, have increased drastically in the last years because of their exceptional manufacturing flexibility and capabilities. Designers can produce parts of any geometrical shape using a wide range of materials currently available. However, the mechanical performance of parts made in AM systems is still uncertain; this because of the great influence of the process parameters on the mechanical properties of AM parts. Unlike most conventional manufacturing processes, the AM process parameters may have a significant effect on the final properties of the part, which could drastically differ from the unprocessed material. Every single combination or variation of the AM process parameters, such as layer thickness, infill percentage, infill orientation, build orientation, number of shell perimeters, process temperature, process speed, etc., will cause the part to have different values of mechanical strength, mechanical strain, elastic modulus, anisotropy, among others mechanical properties. Several works in the literature that have studied the influence of process parameters on the mechanical properties of AM parts, in particular FDM (Fused Deposition Modelling) parts, based on experimental tests. A limited number of investigations have focused on the analysis and prediction of the mechanical properties of AM parts using theoretical and numerical approaches such as the Finite Element Method (FEM); nevertheless, their results have been not accurate yet. The prediction of the mechanical properties of AM parts is very important in order to design and fabricate parts not only of any geometrical shape but also with variable or customized mechanical properties. Thus, more research work is needed in order to develop reliable prediction models able to estimate the structural performance of AM parts before fabrication. In this paper the analysis and numerical simulation of the mechanical performance of FDM samples with variable infill values is presented. The aim is to predict the mechanical performance of FDM components using numerical and analytical models. Thus, several standard tensile test specimens were fabricated in an FDM system using different percentages of infill values, a constant layer thickness, one shell perimeter, and PLA material. These samples were measured and modelled in a CAD system before carrying out the experimental tensile tests. Numerical models and simulations based on the FEM method were then developed and carried out in order to predict the structural performance of the specimens. An existing theoretical model was also used to predict the specimens’ structural performance. Finally the experimental, numerical and theoretical results were compared and conclusions drawn.