The effect of fatigue cracks on fastener flexibility, load distribution, and fatigue crack growth

Publication Type dissertation
School or College College of Engineering
Department Mechanical Engineering
Author Whitman, Zachary Layne
Title The effect of fatigue cracks on fastener flexibility, load distribution, and fatigue crack growth
Date 2012-05
Description Fatigue cracks typically occur at stress risers such as geometry changes and holes. This type of failure has serious safety and economic repercussions affecting structures such as aircraft. The need to prevent catastrophic failure due to fatigue cracks and other discontinuities has led to durability and damage tolerant methodologies influencing the design of aircraft structures. Holes in a plate or sheet filled with a fastener are common fatigue critical locations in aircraft structure requiring damage tolerance analysis (DTA). Often, the fastener is transferring load which leads to a loading condition involving both far-field stresses such as tension and bending, and localized bearing at the hole. The difference between the bearing stress and the tensile field at the hole is known as load transfer. The ratio of load transfer as well as the magnitude of the stresses plays a significant part in how quickly a crack will progress to failure. Unfortunately, the determination of load transfer in a complex joint is far from trivial. Many methods exist in the open literature regarding the analysis of splices, doublers and attachment joints to determine individual fastener loads. These methods work well for static analyses but greater refinement is needed for crack growth analysis. The first fastener in a splice or joint is typically the most critical but different fastener flexibility equations will all give different results. The constraint of the fastener head and shop end, along with the type of fastener, affects the stiffness or flexibility of the fastener.
Publisher University of Utah
Subject Aircraft; Fatigue crack; Joint; Load distribution; Multifastener; Stress intensity
Subject LCSH Metals -- Fatigue; Metals -- Cracking; Airplanes -- Design and construction
Dissertation Institution University of Utah
Dissertation Name Doctor of Philosophy
Language eng
Rights Management Copyright © Zachary Layne Whitman 2012
Format Medium application/pdf
Format Extent 18,575,423 bytes
Identifier us-etd3/id/702
Source Original in Marriott Library Special Collections, TA7.5 2012 .W45
ARK ark:/87278/s60s045b
Setname ir_etd
Date Created 2012-05-07
Date Modified 2018-04-18
ID 194857
Reference URL
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