Do not read so much, look about you and think of what you see there – Feyman
No problem is too small or too trivial if we can really do something about it – Feyman
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No problem is too small or too trivial if we can really do something about it – Feyman
description
No problem is too small or too trivial if we can really do something about it
– Feyman. H 2 C-C-C{-O- -C- -O-} n C-C-CH 2. H. H. H. H-C-H. H-C-H. O. O. H. H. H. H 2 N-R-NH 2. hardener. epoxy. Prepregs. Some specific polymers. angular WC fragments. - PowerPoint PPT Presentation
Transcript of No problem is too small or too trivial if we can really do something about it – Feyman
No problem is too small or too trivial if we can really do something about it
– Feyman
H2C-C-C{-O- -C- -O-}nC-C-CH2
H-C-HH
H-C-HH
epoxy
H
H OO
H
H
hardenerH2N-R-NH2
Prepregs
Some specific polymers
Composites - overview
Example - carbide tools (previously discussed)
Co matrix phase
angular WC fragments
Composites - overview
Artificial combination of matrix phase & dispersed phase
Matrix:metal, alloyceramic mat'lpolymer
Dispersed phase:particulatefiber
Composites - metal matrix composites (MMCs) Particulates:
ThO2-dispersed Ni (TD Ni)sintered Al powder (SAP)
- except strengthening maintained at hi T
Improves:strengthcreep resistancehi T corrosion resistance
Works like precipitation hardening
Composites - metal matrix composites (MMCs) Fibers:
Conts - C, SiC, B, Al2O3
Disconts - C, Al2O3 , SiC whiskers
May get rxn betwn phases at hi T
Matrix mat'ls
Composites - ceramic matrix composites (CMCs)
Particulates, fibers:SiC, B, Al2O3 , C, SiC & Si3N4
whiskers
Improve fracture toughness:slow crack growth
deflect crack tipsredistribute stresses around crack
tipsbridge crack tips
Matrix
Composites - polymer matrix composites (PMCs)
Fibers:mainly - glass (GFRPs), carbon (CFRPs),
aramid,others - B, SiC, Al2O3
Composites - polymer matrix composites (PMCs) Matrix
Composites - polymer matrix composites (PMCs)
Very common - polyesters, vinyl esters
Composites
Role of matrix in FR composites:a. transfer stresses betwn fibersb. provide barrier to environmentc. protect fibers
Matrix/fiber bond:matrix must wet fiber physical & chemical bond desirablemechanical interlocking
Fibers frequently coated w/ coupling agent
non-coupled
Composites
coupled
Composites
Fibers - variablesamountfiber lengthdistributionorientation
Fiber orientation can berandom aligned intermediate
Assignment:
Review today's classnotes
a. epoxiesb. composites - matrix, dispersed
phasec. MMCs - strengthening mechanismd. CMCs - fracture toughness
improvese. PMCs - fibersf. matrix/fiber bond
Read pp. 481-507, 527-538
Composites - polymer matrix composites (PMCs)
Role of matrix in FR composites:a. transfer stresses betwn fibersb. provide barrier to environmentc. protect fibers
Slow crack growthdeflect crack tipsredistribute stresses around crack
tipsbridge crack tips
