98,573 research outputs found
The effect of defects and notches in quasi-static and fatigue loading of Inconel 718 specimens produced by selective laser melting
No full textAdditively manufactured components are likely to contain defects deriving from the manufacturing process. They are also likely to be designed with high geometric complexity (including notches), due to very few design-limitations. In order to understand the influence of these two types of geometric features, we here investigate as-built Inconel 718 specimens produced by selective laser melting under quasi-static and cyclic loading. Notched and unnotched specimens are considered, and the main emphasis is set on the influence of the defects and on how they influence the failure locations at different load levels. © 2020 The Author(s
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
A 349 Bjugn kirke. To senmiddelalderske fløydører. Restaureringsrapport
No full textFramlagt til eksamen for teknisk konservator. Oslo, 1985. NB: Stor fil, vil ta tid å åpn
Hal Campbell and Sarah Solberg
No full textDr. Sarah Solberg and Dr. Hal K. Campbell rehearse for SUSC's Faculty Winter Winds Recital
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Notch-Defect Interaction in Additively Manufactured Inconel 718
No full textPowder bed fusion based additively manufactured components are known to have poor surface quality, especially when building downward facing surfaces. These surfaces can contain defects, from which fatigue cracks can be initiated. In this work the notched fatigue behaviour of Inconel 718 specimens produced by selective laser melting is investigated. The main focus is set on the interaction between notch geometries and local defects due to the amount of overhang in the notch region. Four different geometries are considered, with different amount of notch acuities and degree of downward facing surfaces. A variation in failure sites, with respect to the notch bisector line, was fond in the specimens, and the position was found to be dependent on the amount of overhang and notch acuity. The fatigue life was found to be dependent on the size of surface defects measured in fracture surfaces. Further, the use of average strain energy density as a failure criteria in additively manufactured metals is discussed
What is going on with fatigue of additively manufactured metals?
No full textThis brief communication gives an overview of fatigue behaviour and assessment of additively manufactured metals. The high cycle fatigue behaviour of as‐built and post‐processed additively manufactured superalloy 718, stainless steel (316L and 17‐4PH), and Ti‐6Al‐4 V is compared with their wrought counterparts. Further, different approaches used for assessment of the fatigue behaviour are presented
Formation of fully equiaxed grain microstructure in additively manufactured AlCoCrFeNiTi0.5 high entropy alloy
No full textIn this work, the non-equiatomic high entropy alloy AlCoCrFeNiTi0.5 was additively manufactured via the laser engineered net shaping (LENSTM) process. Contrary to the columnar grain microstructure commonly observed in previously reported alloys, the as-deposited AlCoCrFeNiTi0.5 specimens exhibit a fully equiaxed grain microstructure in a wide range of temperature gradients G (85 to 1005 K/mm) and solidification velocities V (5 to 20 mm/s). The main microstructural characteristics were found to be B2-structured proeutectic dendrites delineated by lamellar or rod-like B2/A2 eutectic structures. The formation of this microstructural feature can be discussed with the aid of Scheil's solidification model. The proeutectic B2-structured dendrites were frequently found to be fragmented, which may provide profuse effective nucleation sites, and hence promote equiaxed grain formation. Furthermore, we estimated the volume fraction φ values of equiaxed crystals at solidification front for various G - V combinations established in this paper, which can provide a theoretical basis for our experimental findings. The current work provides guidelines for producing fully equiaxed alloys by the additive manufacturing (AM) process
Static and fatigue behavior of injection molded short-fiber reinforced PPS composites: Fiber content and high temperature effects
No full textTwo different short glass fiber reinforced PPS composites with different fibers content (30% and 40% in weight) were tested upon static and fatigue loading at room temperature. The material with 40% fiber content was also tested at high temperature (160 °C) both in static and fatigue condition. All the specimens were injection molded directly in standardized dog-bone geometry without further cutting or machining. Static tests at three different displacement rates were performed in order to calculate the main static mechanical properties and to observe the strain-rate sensitivity. Fatigue tests for both materials were performed in load control with 0.1 load ratio. The S-N curves are presented in semi-logarithmic coordinates. Some derived cyclic parameters such as the cyclic mean strain and cyclic modulus were calculated to observe the capability to describe the input test variables effect on the damage mechanism. The fracture location distribution along the specimen longitudinal axis were observed and the transverse cross-sections were analyzed by means of optical microscopy in order to correlate the micro-structure and the mechanical properties. © 2021 Elsevier Lt
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