2nd european htc – strasbourg francisco roman · patran •2d quad4 elements ... – shell...

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


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


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


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


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…


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


Design

• Composites design:

– Low curvatures

– “Large” pieces of fibre

– No sharp corners

– Easy assembly


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


FE Model

LIR

Drive Strut

Diaphragms

Clamp Rib 2

Bottom + Spars

Top

Clamp Rib 8

• Assembly of components


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


FE Model - Loads

– Most critical cases

– Complicated interaction bolt-LIR

– 1D element as bolt

– MultiPoint Constraint in the lug:

120°MPC in Load direction


Analysis

– Stress Analysis of Flap

• Well distributed stresses

=> Uncritical Stresses

– Stress Analysis of LIR (RIB)

• Rib and distributor

• Distributed Stresses

• Max. Stress Criteria


– Stress Analysis of LIR (Flanges)

• Load Introduction

• Local high Stresses

• 3D Failure Criteria SPC



Analysis

– Stress Analysis of Gusset Fillers

• Modeled as resin

• Local High Stresses



– Stress Analysis of LIR Corners

• Local High 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


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


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


Thank You For Your Attention!


Questions?

2nd european htc – strasbourg francisco roman · patran •2d quad4 elements ... – shell...

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