1st phase of poject

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


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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

1st phase of poject

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