In this study a methodology is developed for the fatigue and fracture analysis of helicopter
fuselage structures, which are considered as the stiffened panels. The damage tolerance
behavior of the stiffened panels multiaxially loaded is investigated by implementing virtual
crack closure technique (VCCT). Validation of VCCT is done through comparison between
numerical analysis and the studies from literature, which consists of stiffened panels
uniaxially loaded and the panel with an inclined crack. A program based on Fortran
programming language is developed to automate the crack growth analysis under mixed
mode conditions. The program integrates the prediction of the change in crack propagation
direction by maximum circumferential stress criterion and the computation of energy release
rate by VCCT. It allows reducing the computation time for damage tolerance evaluation for
mixed mode cases through finite element analysis and runs the procedure file of
MSC.Marc/Mentat for numerical analysis and the program generated by Patran Command
Language (PCL) of MSC.Patran for remeshing. The developed code is verified by comparing
the crack growth trajectories obtained by numerical analysis with the experimental studies
from literature. A submodeling technique is utilized to analyze a particular fuselage portion of
helicopter tail boom. Effects of different skin/stringer configurations of the helicopter fuselage
structure on stress intensity factor are studied by means of the developed program. Fatigue
crack growth analysis is performed by using stress intensity factors obtained from numerical
analysis and fatigue propagation models proposed in literature.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12615497/index.pdf |
| Date | 01 February 2013 |
| Creators | Ozcan, Riza |
| Contributors | Dag, Serkan |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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