Force-based Finite Element for Large Displacement Inelastic Analysis of Frames
Lecture #9 Analysis of fuselage frames using the force method.
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Transcript of Lecture #9 Analysis of fuselage frames using the force method.
Lecture #9Analysis of fuselage frames usingthe force method
Airbus A300
FUSELAGE FRAMES
2
FUSELAGE FRAMES - SURVIVABILITY
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Boeing 737, Aloha Flight 243
Airbus Beluga
FUSELAGE FRAMES
4
FUSELAGE FRAMES
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Antonov An-225
Airbus A380
FUSELAGE FRAMES
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FUSELAGE FRAME LOADS
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Typical loads acting on the fuselage frame are:
- distributed load due to inside pressure;
- concentrated forces;
- bending moments from wings;
- distributed shear load to balance shear forces.
FUSELAGE FRAMES ANALYSIS
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When analyzing fuselage frames, one must remember about:
- the usage of symmetry and anti-symmetry;
- internal pressure could be studied separately, basing on superposition principle;
- the internal statical indeterminacy due to the closed contour:
cc – number of closed contours (cells)
2 2 3 3i r c h n d cc
METHODS TO ANALYSE FUSELAGE FRAMES
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Slope-deflection method
Force method
Small degreeof statical
indeterminacy
Large degreeof statical
indeterminacy
Slope-deflection methodin matrix formulation
Numerical methods
EXAMPLE OF FORCE METHOD APPLICATION
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FLOWCHART OF SOLUTION USING FORCE METHOD
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Classificationof the problem
Basic system
Loaded andunit states
Redundant constraints are removed
In loaded state, external load is applied. In unit states, unit force is applied instead of constraint.
Canonical equations
Total stress state
Forces in removed constraints are determined
Displacements corresponding to removed constraints are
determined for each state
EXAMPLE OF FORCE METHOD APPLICATION
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EXAMPLE OF FORCE METHOD APPLICATION
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EXAMPLE OF FORCE METHOD APPLICATION
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EXAMPLE OF FORCE METHOD APPLICATION(NUMERICAL SOLUTION)
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EXAMPLE OF FORCE METHOD APPLICATION #2
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EXAMPLE OF FORCE METHOD APPLICATION #2(NUMERICAL SOLUTION)
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EXAMPLE OF FORCE METHOD APPLICATION #3
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EXAMPLE OF FORCE METHOD APPLICATION #3(NUMERICAL SOLUTION)
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WHERE TO FIND MORE INFORMATION?
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For force method, I recommendKassimali. Structural Analysis. 3rd ed. 2005Chapter 13
For fuselage frames, go to Megson. An Introduction to Aircraft Structural Analysis. 2010Chapter 5
… Internet is boundless …
TOPIC OF THE NEXT LECTURE
21
Displacement methods
All materials of our course are availableat department website k102.khai.edu
1. Go to the page “Библиотека”2. Press “Structural Mechanics (lecturer Vakulenko S.V.)”