2nd european htc – strasbourg francisco roman · patran •2d quad4 elements ... – shell...
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EA D S INNOVA TION W ORKS
Analysis of Innovative Composite Aircraft Structures
2nd European HTC – Strasbourg
Francisco Roman
Dr. Tamas Havar
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 2
Overview
• Introduction
• Process
• Tools
• Design
• FE Model
• Analysis
• Summary
• Outlook
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 3
Introduction
• Continuous development of aircraft structures
• Increased use of composite materials
• Composites currently used in frame structures
• Metallic Load Introductions
High Lift System:
• Full Composite
– Skins with Stringer
– Ribs and Spars
• Except Metallic Load Introduction Rib
Aim:
Innovative Composite Design for Load Introduction Rib
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 4
Introduction
• Current metallic LIR Composite LIR
• Same function, same space, different concept
New composite LIR concept:
• Functions: Rib, connection and driver
• Feasible geometry for Composites
• Application to a wide range of aircrafts
• Area needed for rivets
Aim: Weight reduction
Manufacturing Simplification
Flap
LIR
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 5
Process
• Analysis of new Concept
Modification of Flap FEM
New Design of LIR
New FEM
Model of LIR
Integration of
LIR Model in
Flap Model
Integration
of Rivets
Part C
Part B
Part A
Application
of Loads
Analysis of
Stresses
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 6
ToolsCATIA
Hypermesh
Abaqus Solver
Hyperview
Hyperview-Player
Abaqus
Viewer
Analytical
Calculations
Patran
•2D Quad4 Elements
•Boundary Conditions
•3D Cat-Product•LIR with Substructure
•Global Results… •Local Stresses… •Rivets…
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 7
Design
2 Components
- LIR -> Load Introduction and Rib
- Drive Strut Fitting -> Driving of the flap Stringer
Skin
Rib
Load Introduction
Reinforcements
Stringer
SkinLIR:
– High thickness as bolt connector
– Low thickness as rib attachment
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 8
Design
• Composites design:
– Low curvatures
– “Large” pieces of fibre
– No sharp corners
– Easy assembly
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 9
FE Model
Flap:
– Course Flap Mesh (20K Elm)
– Shell Elements
– 2D Composite Properties
– Plane Stresses
LIR:
– Fine LIR Mesh (100K Elm)
– Solid Elements
– 3D Composite Properties
– 3D Stresses
– Modeling of
• Diaphragms
• Gusset Fillers
• Lugs
• Significant Spars
• Attachments
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 10
FE Model
LIR
Drive Strut
Diaphragms
Clamp Rib 2
Bottom + Spars
Top
Clamp Rib 8
• Assembly of components
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 11
FE Model - Rivets
• Rivets
– Connection between LIR and Flap
– High number of rivets
– Elastic rivet -> Elastic connection
– Connects Shells and Solids
• MultiPoint Constraints:
– All layers attached to surface
– Distributes load along thickness
– Avoids internal non-realistic
delamination
• 1D Element:
– Punctual connection
– Elasticity of rivets
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FE Model - Loads
– Most critical cases
– Complicated interaction bolt-LIR
– 1D element as bolt
– MultiPoint Constraint in the lug:
120°MPC in Load direction
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Analysis
– Stress Analysis of Flap
• Well distributed stresses
=> Uncritical Stresses
– Stress Analysis of LIR (RIB)
• Rib and distributor
• Distributed Stresses
• Max. Stress Criteria
=> Uncritical Stresses
– Stress Analysis of LIR (Flanges)
• Load Introduction
• Local high Stresses
• 3D Failure Criteria SPC
=> Uncritical Stresses
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Analysis
– Stress Analysis of Gusset Fillers
• Modeled as resin
• Local High Stresses
• Max. Stress Criteria
=> Uncritical Stresses
– Stress Analysis of LIR Corners
• Local High Stresses
• Max. Stress Criteria
=> Uncritical Stresses
RF>=2
2<RF<=1.5
1,5<RF<=1
1<RF<=0.8
RF<0.8
323
1
0
0
0324
– Analysis of Rivets
• Local high Loads
• Rivet / Skin Failure Criteria
=> Rivets are Uncritical
30.9.2008 EHTC 2008 - Francisco Roman - Innovative Composite Aircraft Structures 15
Summary
• New Innovative Composite Design Concept for Load Introduction Rib
• Aim of weight saving and simplified manufacturing reached
• Innovative design and enhanced analysis of the Load Introduction Rib shown
• Extensive Analysis Show Sufficient Strength to withstand all critical Loads
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Outlook
• Preforming of Final Composite LIR
• Final Tool and Infiltration of LIR Prototypes
• Verification of Design in Full Scale Structure Test
• Validation of Analysis with Results of Structure Test
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Thank You For Your Attention!
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Questions?