Post on 21-Oct-2014
description
PEELING OF COMPOSITE SANDWICH
STRUCTURE(C.S.S )
GROUP PRESENTER AND SUPERVISOR
SUPERVISOR :
DR ZAHURIN BINTI HALIM
PRESENTER :
1) NURUL NAJWA AHMAD 0822450
2) SITI NORAINI KAWAEED 0724126
3) MOHD BUKHARI YAHYA 0827361
DEFINITIONS
PEELING : A piece or strip, as of skin or vegetable rind, that has been peeled off.
COMPOSITE : Made up of distinct components; compound.
CONTINUE.. SANDWICH : A laminar construction, consisting of
thin facings bonded to a relatively thick lightweight core,resulting in a rigid and lightweight panel. In this standard, bonded means “joined by welding, brazing or adhesive. ”
STRUCTURE : 1. Something made up of a number of parts that are
held or put together in a particular way 2. The arrangement or formation of the tissues,
organs, or other parts of an organism.
PROBLEM STATEMENT Weak joints between an outer metal
sheet and the core of sandwich assemblies.
Fracture toughness of the facesheet bond.
Crack defects
INTRODUCTION A composite sandwich structures: 1) special class of composite materials 2) fabricated by attaching two thin but stiff skins
to a lightweight but thick core.
WHAT IS CORE? A lightweight natural, synthetic, or
fabricated material bonded between the facings of
sandwich construction in order to separate the facings. to support them against buckling under
stress.
REVIEW Review of the current state of research related
to the topic : THE FLEXURAL BEHAVIOR OF COMPOSITE SANDWICH STRUCTURE[MOHD HAKIMI BIN OMAR,2008]COMPOSITE SANDWICH STRUCTURE WITH GRID STIFFENED CORE[VENKATA DINESH MUTHYALA,2005]A TEST TECHNIQUE FOR ASSESSING CORE-SKIN ADHESION IN COMPOSITE STRUCTURES
Types of composite sandwich structure
SANDWICH PANEL
foam
HONEY COMB SANDWICH
SANDWICH PANEL
PROCEDURE TEST Problems on the sandwich structure has been
identified from the problem statement: One of them is poor bonding face problem In order to solve that problem, Climbing drum
peel test is used in this case.
PEELING OF C. S. S.
CONTINUE..
PEELING TEST
Climbing drum peel fixture for ASTM D1781
This test method covers the determination of the peel resistance of a sandwich structure and its core
CONTINUE..
-AdvantagesEvaluate strength of skin-core
-DisadvantagesDifficult if the sandwich skin’s is too thin or too thick
APPLICATION
Railway floors, doors, interiors, fairing panels Boat hulls and interior panels and furniture Racing car chassis and body panels Specialist flight cases Helicopter blades Aircraft engine structures Aircraft doors and hatches Aircraft floor panels Racing car structures and aerofoils Energy absorbers
SHIP AND AUTOMOTIVE
DISCUSSION
HOW TO PREVENT PEELING
Apply good original fiber, matrix and resin.
Use suitable core. Honeycomb is one of
good core for composite sandwich structure.
Get the best strength of the weight ratios.
HOW TO REPAIR THE PEELED SECTION.
Cosmetic repair>In this case inspection has determined that the damage has not affected the structural integrity of the component. A cosmetic repair is carried out to protect and decorate the surface. This will not involve the use of reinforcing materials.
STRUCTURAL REPAIR
If the damage has weakened the structure through fibre fracture, delamination or disbonding the repair will involve replacement of the damaged fibre reinforcement, and core in sandwich structures to restore the original mechanical properties.
Since a bonded-on repair constitutes a discontinuity of the original plies, and therefore a stress raiser, structural repair schemes normally require extra plies to be provided in the repair area.
If the damaged area is very small it can be questionable whether a structural repair is required but more preferable to a cosmetic repair
PATCH REPAIR
In this case the thickness of the original laminate is made up with filler plies and the repair materials are bonded to the surface of the laminate.
Advantages> Quick and simple to do>Requires minimum preparation
Disadvantages>A repaired laminate is thicker and heavier than the original>Very careful surface preparation is needed for good adhesion
Conclusion
CONCLUSION Peeling is one of the
major problem in the c.s.s.
It can be prevent by applying good fiber, matrix and resin.
It can be tested using Climbing drum peel fixture
REFERENCES www.sandwichpanels.org/articles/article_whatisasandwich.html
http://jcm.sagepub.com/content/38/10/805.abstract
http://www.com-ten.com/climbing-drum-peel-fixture-astm-d1781.html
The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company
Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003