A novel adaptive displacement-controlled test setup was developed for fatigue testing on mini specimens. In property characterization of additive manufacturing materials, mini specimens are preferred due to the specimen preparation, and manufacturing cost but mini specimens demonstrate higher fatigue strength than standard specimens due to the lower probability of material defects resulting in fatigue. In this study, a dual gauge section Krouse type mini specimen was designed to conduct fatigue tests on additively manufactured materials. The large surface area of the specimen with a constant stress distribution and increased control volume as the gauge section may capture all different types of surface and microstructural defects of the material. A fully reversed bending (R = -1) fatigue test was performed on simply supported specimens. In the displacement-controlled mechanism, the variation in the control signal during the test due to the stiffness variation of the specimen provides a unique insight into identifying the nucleation and propagation phase. The fatigue performance of the wrought 304 and additively manufactured 304L stainless steel was compared applying a control signal monitoring (CSM) method. The test results and analyses validate the design of the specimen and the effective implementation of the test bench in fatigue testing of additively manufactured materials.
M. M. Parvez et al., "A Displacement Controlled Fatigue Test Method for Additively Manufactured Materials," Applied Sciences (Switzerland), vol. 9, no. 16, MDPI AG, Aug 2019.
The definitive version is available at https://doi.org/10.3390/app9163226
Materials Science and Engineering
Mechanical and Aerospace Engineering
Center for Research in Energy and Environment (CREE)
Keywords and Phrases
304l Stainless Steel; Adaptive Control; Additive Manufacturing; Fatigue Testing; Mini Specimen; Simply Supported Bending
International Standard Serial Number (ISSN)
Article - Journal
© 2019 The Authors, All rights reserved.
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01 Aug 2019
This research was supported by National Science Foundation Grant CMMI-1625736. Part of the work was also funded by the Department of Energyâ€™s Kansas City National Security Campus which is operated and managed by Honeywell Federal Manufacturing Technologies, LLC under contract number DE-NA0002839.