Characterization of stiffness degradation caused by fatigue damage of additive manufactured parts

Abstract

A study of the cyclical fatigue behavior of additive manufactured components, fabricated by the fused deposition modeling (FDM) process, is presented. Experimentation was designed to focus on the effect of deposition strategy or specimen mesostructure on tensile fatigue life and effective stiffness. Testing included consideration of unidirectional laminates with parallel plies having fiber orientations ranging from  = 0° to  = 90°, and bidirectional laminates with alternating orthogonal plies that form a layering pattern of °/(-90°) fiber orientations. Results highlight the orthotropic behavior of FDM components and suggest that tensile performance is improved by aligning fibers of unidirectional laminae more closely with the axis of applied stress. The bidirectional laminae display incrementally improved tensile fatigue performance from what appears to be an offsetting effect associated with alternating orthogonal layers. An empirical model of effective elastic modulus and an analytical model of the accumulated damage state, as defined on the basis of stiffness degradation during cyclical loading, are presented as functions of specimen mesostructure. The actual damage accumulation due to cyclical loading is compared with the model predictions, and the coefficient of determination R 2 indicates reasonable agreement for each factor combination.

Filament Materials Screening for FDM 3D Printing by Means of Injection‐Molded Short Rods

“…The Young's moduli ( E ) of 90° specimens are around 10% to 20% lower than the 0° specimens. This is in agreement with other studies of tensile specimens with different raster orientation . In Figure b, two curves of typical strong and tough properties of bulk PP are observable as the 0° specimens consist of parallel‐oriented fused ribbons along the tensile loading direction.…”

Study of Different Printing Design Type Polymer Samples Prepared by Additive Manufacturing

“…The best tensile properties are obtained when filaments are oriented longitudinally and parallel to the loading direction, and the worst tensile properties are obtained when samples are loaded along the build direction due to weak interlayer bonding [28,29]. For ABS samples, the largest ultimate strength was observed for 0° raster angle compared to 45° and 90° raster angles [30]. The honeycomb is a very common test structure of 3D models [31].…”

Mechanical Characterization of Additively Manufactured Parts by FE Modeling of Mesostructure

“…Liu and Shapiro [21] proposed a new approach to find the elastic moduli of the parts fabricated by FDM, in which mesostructure is accounted for homogenization at macro scale level using Green's function. An experimental fatigue damage analysis of FDM processed parts was carried out in [22]. Further, deposition strategy influences the mesostructure and its effect on the fatigue life of the parts was investigated.…”