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7/31/2019 1st Phase of Poject
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Stress Analysis of Stiffened Panel
with Two Bay Crack Under Biaxial
Loading
By,
Avinash V DharwadkarBVBCET
7/31/2019 1st Phase of Poject
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Contents
Introduction
Sources of local damage
Problem Definition
Scope of the project
Literature survey
Stiffened panel
Conclusion
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Introduction
Aircrafts are complex structure of stiffened panels. The
stiffeners are the main components there are various types of
stiffeners being used based on type of the parts being
manufactred.In this project hat stiffeners are used, crack
stoppers, L bulk heads, Z Transverse stiffeners are used They
are all connected each other by means of rivets. This stiffened
panel is loaded biaxilly,in actual case the pressurized fuselage
inner side there is a pressure acting all over of fuselage as well
as tensile force is acting on either side .
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Sources of local damage
In this project taking small portion of the fuselage i.e. fuselage
cutout creating actual loading conditions analysis will be
carried out in patran and nastran software's by inserting the
two bay crack. Reasons for crack to develop are
Foreign material or pabble may hit the fuselage on the
runway.
Fatigue loading
Tool work in in the assembly hanger.
Engine blades may hit the fuselage in the event of bird hit.
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Problem Statement
Stress analysis of stiffened panel by inserting a two
bay crack in plate.
Effect of biaxial loading.
Length of crack versus load
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Scope of the Project
By the simulation we will come to know the
maximum stresses and deformation.
Von moises stresses and the stresses along Y
component.
Stresses at the crack region.
Simulation of fatigue breaking of the L-bulkheads.
Crack arrest phenomenon is carried out in simulation.
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Broad field of fracture mechanics
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Literature survey
T. Swift,The fatigue and damage tolerance capability
of pressurized fuselage
structure is extremely sensitive to stress level,
geometrical design, and material choice. Considerableimprovements have been made in designing fuselage
structure to sustain large, obviously detectable
damage. The historical evolution of these
improvements isdiscussed.in, Damage Tolerance in
Pressurized Fuselages.
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M. M. Ratwani and D. P. Wilhem, Influence of
biaxial loading on analysis of cracked stiffened
panels.
The analytical results of crack openings and stresses inthe stringer are compared to the experimental results.
It is found that contrary to the behavior of unstiffened
structures, the stress intensity factors values and crack
openings increase for positive biaxial load ratios in
cracked stiffened structures.
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J.R. Yeh, M. Kulak,Fracture analysis of cracked
orthotropic skin panels with riveted stiffeners
The results obtained from the analytical method are
compared with Finite element results. Goodagreement of these results demonstrates the validity
and accuracy of the analytical method. A one-bay
crack and a two-bay crack with center stiffener either
intact or broken are evaluated.
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stiffened panel
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Components
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Fuselage Cutout
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Stiffened panel
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References
T. Swift,The fatigue and damage tolerance capability
of pressurized fuselage.
M. M. Ratwani and D. P. Wilhem, Influence of
biaxial loading on analysis of cracked stiffenedpanels.
J.R. Yeh, M. Kulak, Fracture analysis of cracked
orthotropic skin panels with riveted stiffeners
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Thank you