04.1 - Aerospace Grade Materials, Structural Analysis, Fatigue and Damage Tolerance
FATIGUE CRACK PROPAGATION IN ADDITIVELY MANUFACTURED POLYMER PARTS
H. El Fazani¹, J. Coil¹, J. Laliberté¹; ¹Carleton University , Canada
This study is aimed to assess the fatigue performance of additive manufacturing (AM) parts made from polymer. This will lead to the improvement of AM part designs. A computer aided design (CAD) program is used to design groups of fatigue coupons with dimensions specified in the ASTM D3479 Standards. These specimens are made from a commercial Polymer, acrylonitrile-butadiene-styrene (ABS) P430. A Stratasys SST 1200es fused deposition machine was used to manufacture flat AM coupons. The specimens were also built in different angles of orientations (0°, 22.5°, 45°, 67.5° and 90°). The purpose of this research is to investigate the material behavior under different fatigue loading conditions. It is essential to understand the mechanics underlying the failure process to ensure a high quality of AM end product. Fatigue analysis was conducted and both fatigue initiation and propagation will be investigated, with the focus will be on crack initiation. The proposed test matrix explains the number of tested coupons, where 21 flat specimens are tested with a degree of orientations (0°, 22.5°, 45°, 67.5° and 90°). The fatigue test for this paper is based on measuring the crack length of AM specimen caused by low cyclic fatigue loading. An optical microscopy is used to track the crack upon initiation. Also, multiples cracks are measured within the same AM specimen. The relation between crack length, for individual crack and multiple cracks, versus the number of fatigue cycles is obtained. In addition, the variation of fatigue life with specimens build orientations is discussed. This study will also identify which fatigue test methods are suitable for polymer AM components.