Verification of Stress Transformation in Anisotropic Material Additively Manufactured by Fused Deposition Modeling (FDM)

Abstract

Abstract The widespread use of Additive Manufacturing (AM) has been extensively progressed in the past decade due to the convenience provided by AM in rapid and reliable part production. Fused Deposition Modeling (FDM) has witnessed even faster growth of application as its equipment is environmentally-friendly and easily adaptable. This increased use of FDM to manufacture prototypes and finished parts is accompanied by concerns that 3D printed parts do not perform the same as relatively homogeneous parts produced by molding or machining. As the interface between two faces of bonded material may be modeled by stress elements, in theory by modeling 3D printed layers subjected to tension at varying angles as transformed stress elements, the stress required to break the layer bonds can be determined. To evaluate such a relationship, in this study, the stresses calculated from stress transformation were compared with the behavior of 3D printed specimens subjected to tensile loads. The maximum principal stress was found to be constant relative to the layer angle, regardless of whether the specimen experienced failure at the layer interface or within the layer material, although the specimens with layers 75° relative to the load were notable exceptions to this finding. This failure at much lower stresses for the samples used in the 75° tests may be attributed to a possible environmental factor, such as temperature or humidity change, degrading the samples’ structural integrity.