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Full-Text Articles in Mechanical Engineering
Very High Cycle Fatigue Behavior Of Laser Beam-Powder Bed Fused Inconel 718 Considering The Layer Orientation And Surface Finish Effects, Palmer Frye
UNF Graduate Theses and Dissertations
Additive Manufacturing (AM) techniques have recently gained popularity for fabrication of parts used in aerospace applications. Some of these parts may be subjected to cyclic loading at very high frequencies, leading to service life requirements exceeding ten-million cycles (>107 cycles). Therefore, understanding the very high-cycle fatigue (VHCF) behavior of these AM parts is an important step in their design and qualification processes. In this thesis, both high-cycle fatigue (HCF) and VHCF behaviors of Inconel 718, a Ni-base superalloy, manufactured via a Laser Beam-Powder Bed Fusion (LB-PBF) process, are investigated. Uniaxial, fully reversed force-controlled fatigue tests were conducted utilizing …
Efficacy Of Hard Hats In Attenuating Head Accelerations: A Combined Experimental And Computational Investigation, Arthur Aloisio Alves Dos Santos
Efficacy Of Hard Hats In Attenuating Head Accelerations: A Combined Experimental And Computational Investigation, Arthur Aloisio Alves Dos Santos
UNF Graduate Theses and Dissertations
Struck-by accidents are a leading cause of traumatic brain injuries in the construction industry. While hard hats are the conventional means of industrial head protection, the current test standard to evaluate hard hat performance does not assess their ability to mitigate head accelerations from such impacts. To address this gap in knowledge, three investigations were pursued as part of this thesis. First, a variety of commercially available hard-hat designs – differentiated by shell design, number of suspension points, and suspension tightening system – were tested for their ability to attenuate accelerations during vertical impacts to the head. All hard-hats appreciably …