Investigation of Stress Concentrations in Parts Manufactured with Fused Deposition Modeling

Faculty Mentor Name

David Lanning

Format Preference

Poster

Abstract

Fused Deposition Modeling (FDM), a type of additive manufacturing which deposits material layer-by-layer until completion, has experienced significant growth in recent years. FDM is a desirable manufacturing method due to the tailorability and customization which it offers. However, the lack of knowledge concerning the effects of various process parameters can hinder the full-scale implementation in product development. Additionally, there is little to no existing literature pertaining to the application of solid mechanics theories to predict the initiation of failure. The aim of this study is to demonstrate the effects of infill parameters combined with stress concentrations on the fracture of specimens manufactured using FDM. To investigate these effects, infill pattern is constrained to a ‘gyroid’ pattern, and the infill density is varied at 20%, 40%, and 60%. Two specimen geometries were chosen. The first set is a stress inducing hole at the center of the specimen where the hole diameter remains constant while specimen width is increased, effectively increasing the stress concentration factor. The second geometry consists of opposite semicircular edge notches, with a radius chosen such that the stress concentration factor remains constant compared to the first geometry. Solid mechanic theory predicts that the material’s ultimate tensile strength (UTS) will be reduced by the stress concentration factor for the specimen UTS. However, initial results contradict this theory indicating potential reinforcement from the specimen geometry.

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Investigation of Stress Concentrations in Parts Manufactured with Fused Deposition Modeling

Fused Deposition Modeling (FDM), a type of additive manufacturing which deposits material layer-by-layer until completion, has experienced significant growth in recent years. FDM is a desirable manufacturing method due to the tailorability and customization which it offers. However, the lack of knowledge concerning the effects of various process parameters can hinder the full-scale implementation in product development. Additionally, there is little to no existing literature pertaining to the application of solid mechanics theories to predict the initiation of failure. The aim of this study is to demonstrate the effects of infill parameters combined with stress concentrations on the fracture of specimens manufactured using FDM. To investigate these effects, infill pattern is constrained to a ‘gyroid’ pattern, and the infill density is varied at 20%, 40%, and 60%. Two specimen geometries were chosen. The first set is a stress inducing hole at the center of the specimen where the hole diameter remains constant while specimen width is increased, effectively increasing the stress concentration factor. The second geometry consists of opposite semicircular edge notches, with a radius chosen such that the stress concentration factor remains constant compared to the first geometry. Solid mechanic theory predicts that the material’s ultimate tensile strength (UTS) will be reduced by the stress concentration factor for the specimen UTS. However, initial results contradict this theory indicating potential reinforcement from the specimen geometry.