Thermomechanical Fatigue of Chamber Structures

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Thermo-mechanical Fatigue of Chamber Structures
Matteo Cova, Gaicomo Po Nasr M.
Ghoniem University of California, Los Angeles
(UCLA) High Average Power Laser Program
Workshop General Atomics San Diego, CA April 4
5, 2002
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Outline
1. Thermomechanical Loading2. Material
Systems3. Mechanical Design 4. Modeling
Issues 5. Required Experiments
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UCLA FY02 Tasks
(1)    Assessment of the thermo-mechanical
properties for (a) monolithic composites (e.g.
C/C or SiC/SiC). (b) Ceramic, armored
composites (e.g. W on SiC/SiC). (c) Engineered
(e.g. nano-tubes, fiberous, porous, foam, and
tiled). (d) Nano-composite, armored ferritic
steel. (2)    Material design equations,
including neutron damage effects where possible.
Coordinated with (ORNL) (UCSB)
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UCLA FY02 Tasks Cont.
 (3)      Development of micromechanical damage
models for material property changes in the IFE
environment Coordinated with UW  (4)     
Development of structural models for chamber
components, utilizing the capabilities of
geometric modeling and FEM codes. (5)     
Assessment of potential failure modes, and
recommendation for alternate material and/or
system designs to mitigate these modes.
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Thermomechanical Loading
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FW stress depends on geometry and temperature/
pressure ratio
Plate Pressure only
Spherical Shell
Plate Pressure Temperature
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SiC/SiC Composites develop microcracks and lose
modulus
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Material Systems-I
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Material Systems-II
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Material Systems-III
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Mechanical Design-I
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Mechanical Design-II
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Mechanical Design-III
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Mechanical Design-IV
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Modeling Approaches
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Paris Law
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Experimental Needs
(1) S-N-P
(2) da/dn
(3) Threshold Fracture toughness (bulk
interface)