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ءاتونى زبر الحديدحتى إذا ساوى بين الصدفين قال انفخوا حتى إذا جعله نارا فما عليه قطرا أفرغ ءاتونى قال * اسطاعوا أن يظهروه وما استطاعوا له نقبا صدق ا العظيم
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سورة الكهف ،الية 96و97
02/04/13
Hossam Sallam
Fatigue and Fracture Behavior of Composites by .Hossam Sallam, Ph.D ,Materials Engineering Department Zagazig University Hossam Sallam
02/04/13
Objective The goal of this review article is to present a sound background regarding the development of the understanding of the fracture processes and fatigue damage in composite materials and show how they act as a foundation for current models. This presentation shows the importance of matrix, reinforcement, and reinforcement/matrix interface in fatigue and fracture behavior of composite materials. Composites exhibit an unusual combination of brittle .and ductile phenomena Hossam Sallam
02/04/13
out line Introduction Continuous Fiber-Reinforced Composites Short Fiber-Reinforced Composites Particulate-Reinforced Composites Summary
Hossam Sallam
02/04/13
COMPOSITE MATERIALS C L A S S IF IC A T IO N OF C O M P O S IT E M A T E R IA L S w rt R E IN F O R C E M E N T F O R M S F IB E R
PO LY M ER S M ETA LS
D IS C O N T IN U O U S
C E R A M IC S
C O N T IN U O U S
P A R T IC L E L A M IN A T E
Hossam Sallam
w rt T Y P E O F M A T R IX
02/04/13
Introduction to Fracture Mechanics (Linear Elastic Fracture Mechanics (LEFM SIF, K* plain strain fracture Toughness, KIc*
(Elastic-Plastic Fracture Mechanics (EPFM J-integral* (Crack Tip Opening Displacement (CTOD*
Crack tip Deformation* Hossam Sallam
02/04/13
Introduction to Fatigue of Materials Wohler’s S-N Curve, 1871 S
N
Hossam Sallam
ris a P
w La
∆Kth
,
63 9 1
Kc
da/dN
da/dN
da/dN-∆ K curve
∆K 02/04/13
Elber,1970
∆Keff
out line Introduction Continuous Fiber-Reinforced Composites Short Fiber-Reinforced Composites Particulate-Reinforced Composites Summary
Hossam Sallam
02/04/13
Continuous Fiber-Reinforced Composites Fiber Bridging Shear lag Models
•
Fiber Bridging
Crack Front Debonding
Fiber Pull-out
Fiber Pressure model • Matrix Crack Wake Debonding/Sliding
Hossam Sallam
The various mechanisms that accompany mode I matrix crack propagation in unidirectional composites 02/04/13
out line Introduction Continuous Fiber-Reinforced Composites Short Fiber-Reinforced Composites Particulate-Reinforced Composites Summary
Hossam Sallam
02/04/13
1
Short Fiber-Reinforced Composites Fiber Reinforced Concrete
Microcrack
Stress
Microfiber
P
PC Large Fiber
P
Crack
Strain
Illustration of different sizes fibers on crack Hossam Sallam 02/04/13 bridging
1
out line Introduction Continuous Fiber-Reinforced Composites Short Fiber-Reinforced Composites Particulate-Reinforced Composites Summary
Hossam Sallam
02/04/13
1
Particulate-Reinforced Composites Ductile Particle in Brittle Matrix (a )
(b)
•
( c)
The stages of crack propagation Hossam Sallam
02/04/13
1
Brittle Particle in Ductile Matrix
a)
High strength matrix)
& Coarse particles
&b) Strong interface) High modulus of particles
c) Weak interface)
Possible particle-crack tip interactions in fatigue crack growth Hossam Sallam
02/04/13
1
out line Introduction Continuous Fiber-Reinforced Composites Short Fiber-Reinforced Composites Particulate-Reinforced Composites Summary
Hossam Sallam
02/04/13
1
Summary
Crack-Tip Shielding Mechanisms b) Zone Shielding)
a) Crack Deflection)
microcrack toughening-
c) Contact Shielding) Wedging •
Bridging •
corrosion-induced crack closureroughness-induced crack closure-
d) Combined Zone and Contact Shielding) plasticity-induced crack closure-
Hossam Sallam
02/04/13
1
الحمد لله رب العالمين وشكر َا
1
02/04/13
Hossam Sallam