WARSAW UNIVERSITY OF TECHNOLOGY Politechnika Warszawska

FACULTY OF POWER AND AERONAUTICAL ENGINEERING

Wydział Mechaniczny Energetyki i Lotnictwa

DIVISION: Strength of Materials and Structures Zakład: Wytrzymałości Materiałów i Konstrukcji

Anticlastic Behaviour Analysis of Sandwich Honeycomb Core

(Hexagonal) 

Badanie Antyklastycznej Deformacji Rdzenia Przekładkowego o Strukturze Plastra Miodu (Sześciokąta)

Supervisor/Promotor: Dr. Inz. Adam DackoMaster Diploma Thesis PresentationPresented By: SUMIT SINGHStudent Index Number: 265593M.Sc. Aerospace Engineering

2 Presentation Plan

Introduction

Thesis Objectives

Honeycomb Core Modelling

MPC (Constrained Equations) – RBE 3 Application

Loads and Boundary Conditions

Material Properties and Manufacturer Data for Honeycomb Core

Analysis and Results

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3 Introduction

Application of Sandwich Honeycomb Core

Hollow Hexagonal Cells

High Strength to Weight Ratio

Increased Bending Stiffness

Anticlastic/Saddle Behaviour

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4 Thesis Objectives

Anticlastic Behaviour Analysis of a Rectangular Block of Honeycomb Core.

Global Apparent Poison’s Ratios Comparison of Four Different Cell Sized Square Block of Honeycomb Core While Bent Out of Plane.

Out of Plane Bending Comparison of Two thin Plates (Made of Isotropic and Orthotropic Material Respectively) and Honeycomb Core.

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5 Honeycomb Core Modelling

Single Hexagonal Cell Creation and Translation Creation of Elements on Curve and Extrusion

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6 MPC – RBE 3 Application

RBE 3 is an interpolation element which defines a linear relationship between nodal DOFs.

RBE 3 Comprises one Dependent Node and many Independent Nodes.

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7 MPC – RBE 3 Application

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8 Loads and Boundary Conditions

Moments

Displacements

Input Data Descriptions (N.mm)Force (F1,F2,F3) < >

Moment (M1,M2,M3) <0, ±200, 0>

Input Data Descriptions (mm)

Translations (T1,T2,T3) <0, 0, 0>

Rotations (R1,R2,R3) <0, 0, 0>

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9 Loads and Boundary Conditions

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10 Material Properties and Manufacturer Data for Honeycomb core

Material Properties

Manufactures Data for Honeycomb Core

Material E11 (MPa) G11 (MPa) µ

Aluminium 68000 25564 0.33

Sample CodeAluminium

Cell Size (mm)

Core Thickness (mm)

Cell Wall Thickness (mm)

Material Density (ton/mm3)

AL002540 3.2 20 0.025 0.072E-9AL002640 4.8 20 0.038 0.070E-9AL002840 6.4 20 0.038 0.054E-9AL002940 13 20 0.1 0.062E-9

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11 Cell Wall Thickness for Honeycomb core

Assumed Cell Wall Thickness for Numerical Experiments

Cell Size (mm) Cell Wall Thickness 1 (mm)

Cell Wall Thickness 2 (mm)

3.2 0.05 0.14.8 0.05 0.1

6.4 0.05 0.1

13 0.05 0.1

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12 Cell Size Comparison of honeycomb cores

Four Different Cell Sized Honeycomb Core

13 mm Cell Size

4.8 mm Cell Size

3.2 mm Cell Size

6.4 mm Cell Size

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13 Analysis and Results 3.2 mm Cell Size

0.025 mm Cell Wall Thickness

0.05 mm Cell Wall Thickness

0.1 mm Cell Wall Thickness

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14 Analysis and Results 4.8 mm Cell Size

0.038 mm Cell Wall Thickness

0.05 mm Cell Wall Thickness

0.1 mm Cell Wall Thickness

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15 Analysis and Results 6.4 mm Cell Size

0.038 mm Cell Wall Thickness

0.05 mm Cell Wall Thickness

0.1 mm Cell Wall Thickness

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16 Analysis and Results 13 mm Cell Size

0.05 mm Cell Wall Thickness

0.1 mm Cell Wall Thickness

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17 Global Apparent Poison’s Ratios Comparison

0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 1.25 1.3 1.350

2

4

6

8

10

12

14

Cell Size vs. Global Apparent Poison's Ratio

Global Apparent Poison's ratio obtained from manufacturer data cell wall thicknessGlobal Apparent Poison's ratio obtained from 0.05mm cell wall thicknessGlobal Apparent Poison's ratio obtained from 0.1mm cell wall thickness

Global Apparent Poison's Ratio

Cell

Size

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18 Out of Plane Bending of Honeycomb Core with Skin

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19 Material Properties of thin plates

Isotropic Material

Orthotropic Material

Material E11 (MPa) G11 (MPa) µ

Aluminium 68000 25564 0.33

Material E11 (MPa) E22 (MPa) G11 (MPa) µ

S2-Glass Epoxy 52000 11700 7600 0.28

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20 Comparison of Out of Plane Bending between Thin Plates and Honeycomb Core

Isotropic Orthotropic

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21 Comparison of Global Apparent Poison’s Ratio of Thin Plates and Honeycomb Core

-1.5

-1

-0.5

0

0.5

1

1.5

2

Series1; 1.58

-0.99 -0.93

0.0413

Global apparent Poison's Ratio vs. change in materials of thin plate and honeycomb core

Glob

al A

ppar

ent P

oiso

n's

Ratio

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22 Conclusion

Relation between Hexagon Cell Size and Global Apparent Poison’s ratio is not predictable.

Increase in Hexagon Cell Wall Thickness reduces Global Apparent Poison’s Ratio.

Application of Skin on Honeycomb Core Destroys the Anticlastic Behaviour.

Change in Material Doesn’t affect Anticlastic Bending.

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23

Thank Your for Your Attention

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