Constituents Core Materials

Transcription

1 Constituents Core Materials Introduction to Composite Materials 1

2 Core materials AIRCRAFT COMPOSITE STRUCTURE REPAIR Metallic Non metallic Aluminum Honeycomb Foam Wood Introduction to Composite Materials 2

3 AIRCRAFT COMPOSITE STRUCTURE REPAIR LAMINA LAMINA LAMINATE/ MONOLITHIC STRUCTURE LAMINATES CORE SANDWICH STRUCTURE Introduction to Composite Materials 3

4 Introduction to Composite Materials 4

5 First used in 1940 s. Nomex honeycomb Typically Hexcel HRH 10 Meta aramid fiber with phenolic resin Kevlar N636 reinforced honeycomb Para amid fiber with phenolic resin Glass fiber reinforced plastic honeycomb Glass fiber with phenolic resin Aluminum honeycomb Introduction to Composite Materials 5

6 Density U.O. M Kg/m 3 Nomex HRH GFRP Core Kevlar N Aluminum Alloy 5052 Compressive Strength MPa Shear Strength in L Direction Shear modulus in L- Direction Shear strength in W direction Shear modulus in W direction MPa MPa MPa MPa Absorption in humidity % <5 N/A In use temp range 0 C -55 ~ ~ ~ ~ 175 Modulus to Composite Materials 6

7 Advantages Drawbacks Nomex HRH HRP Glass Kevlar N636 Available with small cell size and low density Tough Easy to Bond when dry Easy to form Formadable Fire resistant, self extinguish Good thermal and electrical insulation up to C High shear properties +/-45 0 Fiber orientation Higher modulus and strength than NOMEX Low moisture absorption Good thermal and electrical insulation up to C High Prices Water migration Good fatigue & impact strength Dimensioanl stability 2X modulus Higher strength Better hot wets 25% weight reduction over GFRP core Low CTE up to C Introduction to Composite Materials 7

8 Manufacturing honeycomb core Introduction to Composite Materials 8

9 Core material properties AIRCRAFT COMPOSITE STRUCTURE REPAIR Expanding direction HRH10 1/8 3.0 Material Designation Cell Diameter Density ECA Introduction to Composite Materials 9

10 Introduction to Composite Materials 10

11 Rigid Curvature is perpendicular to the ribbon direction Facilitate curving in L direction. Have higher W shear properties and decrease L shear properties. Easy to form complex curve. Provide higher shear strength. Introduction to Composite Materials 11

12 Lowly loaded part Highly loaded part Sandwich Structure Monolithic Structure Introduction to Composite Materials 12

13 Advantages Monolithic Structure Sandwich Structure Saving in the maintenance of the aircraft Higher energy impact resistant No fluid ingress problem Bolted repair possible in panel area Best stiffness versus weight ratio Good twisting stiffness Excellent thermal insulation Excellent acoustic damping properties Introduction to Composite Materials 13

14 Drawbacks Monolithic Structure Sandwich Structure Heavy if compared to sandwich structure Heavy weight ratio to stiffness Necessity of stiffening structure for twisting and compression resistance Sensitive to water ingress and various liquid agent Impact sensitive compared to monolithic Bolted repair are not recommended Introduction to Composite Materials 14

15 Introduction to Composite Materials 15