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9 Cards in this Set
- Front
- Back
AutoClave
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Heater Pressure Vessel
-designed/built to ASME code - redundant safety features Instrumentation - thermocouples - pressure and vacuum gages Control System - computer operated, controlled - programmable -data acquisition |
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AutoClave: Advantages
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- Typical Prepreg resin needs pressure to flow and evacuate voids
- Proper Curing - Toughned resin systems - Thermoplastic Composites - Legacy Technology |
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Composite Processing
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Properly cure advanced fiber-reinforced, aerospace grade ploymer-matrix composite materials
-heat - consolidation pressure - vacuum Majority of carbon fiber aerospace components are processed in autoclaves |
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Composite Processing Steps
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A: Initial heat ramp from room temperature
B: Dwell (hold) after set-point temperature attained C: Pressure ramp initiation after minimum T/C reaches temperature D: Heat ramp to next setpoint E: Exotherm of composite part F: Final dwell at cure temperature G: Cool down after required cure time H: Pressure release I: Vacuum held throughout cure cycle |
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Goals of autoclave cure
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* Proper bleed (fiber volume, consistent density)
* Consolidation (interlaminar strength & toughness) * Fiber Volume (in-plane properties) * Low Void Content (fatigue & environmental effects) * Surface requirements (application dependent) * Dimensional stability/tolerance |
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Hand Layup Characteristics
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Hand Layup Characteristics
* Relatively labor intensive - ply cutting - ply positioning - bagging * Single-component fabrication technique - multiple stage possible * Material costs - prepreg - bagging supplies - tooling (typically non-recurring) * High precision - accurate ply location & repeatability |
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Composite Testing
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ASTM D 4762-04
Standard Guide for testing polymer matrix composite materials |
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Composite Testing
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Orthotropic/Anisotropic (composites) vs Isotropic (metals)
Test specimen design Machining/preparation Failure modes Environmental conditions |
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Various Composite test specimens
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In-plane or interlaminar shear
Mode I fracture Interlaminar Shear Open hole tension Bearing Impact Properties |