Fatigue properties of metallic additively manufactured samples

Abstract

The present research was focused in the comparison between four designs of metallic additive manufactured samples with different stress concentrator on each design. The approach was to manufacture a batch of samples from each design and compare the fatigue performance (SN Curve). In this work, the batches of samples were manufactured of 316L stainless steel alloy and the four designs of samples were tested, one design consists in a solid bar and the other three designs were developed with a hole as a stress concentrator in the middle of the bar, the diameter of the holes varies through the three different designs. The advantage of using 3D printing is that this process is easier to manufacture and use than the traditional manufacturing, especially for complex structures, that is why it has become in one of the main alternatives to manufacture industrial parts with the use of high performance metals and polymers. To evaluate the aforementioned performance, in terms of manufacturability a geometry validation of each design has been done. The design of experiments was proposed to present the detail of the characterization of the experiments based on an infrared thermography. The temperature patterns of the hot spot zone are tightly linked with the physical evolution of the fatigue damage. To achieve the objective of the research and obtain an accurate Stress vs Number of cycles to failure (SN curve), an statistical analysis of each measurable variable was made, this to observe the performance of the samples from each design. The remarkable results obtained, were used to provide a viable guidelines to select a manufacturing process oriented to present solid recommendations in order to contribute for future works an affordable additive manufacturing process to utilize in industrial parts, this based in the performance of the specimens.