Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
|
Anisotropic
|
Different properties in different directions
|
|
|
Orthotropic
|
One set of three mutually perpendicular planes of symmetry
|
|
|
Quasiisotropic
|
Three or more plies oriented at equally spaced angles.
OR A laminate of quasiisotropic plies |
|
|
How do you avoid tensile/bending coupling?
|
Use a symmetric laminate
|
|
|
How do you avoid bending/twisting coupling?
|
For every ply oriented at + theta there is a ply oriented at - theta, equidistant from the midplane of the laminate
|
|
|
Balanced Laminate
|
For each ply at theta there is a ply at - theta. (Says nothing about being equidistant)
|
|
|
When is interfacial stress maximized?
|
When plies have greatest angluar differences. Ex: 0 and 90 Degrees.
|
|
|
Unidirectional is good in what loading?
|
Tension
|
|
|
How do you prevent cracking in unidirectionals?
|
Add a little angular difference rather then pure uni.
|
|
|
What is the Q Matrix?
|
Stiffness Matrix
|
|
|
What is the S Matrix
|
Compliance Matrix
|
|
|
What is the S Inverse Matrix?
|
Q Matrix
|
|
|
How many elastic constants are needed for the Q matrix?
|
4
|
|
|
What are the elastic constants needed for the Q matrix?
|
EL
ET VLT GLT |
|
|
[0/+-15/30/45/10]s What is the B matrix?
|
All zeros! Because the laminate is symmetric
|
|
|
What is the A matrix?
|
Extensional Stiffness Matrixq
|
|
|
What is the D matrix?
|
Bending Stiffness Matrix
|
|
|
What is the B matrix?
|
Coupling Stiffness Matrix
|
|
|
Four main modes of failure
|
Facing Failure
Shear Failure of the Core Core Crushing Deflection |
|
|
What is the most effecient and idealistic bridge?
|
All modes fail at once
|
|
|
Name Four Edge Treatments for Honeycomb
|
- Extrusion
- Potting Compound to fill edges - Taper laminate to solid - Fold facing over to cover edge - Add solid insert - Wrap facing over solid part - Crush core into taper - fill - Foam insert on edges |
|
|
How do you taper a facing?
|
Stagger ply lengths - make each ply shorter
|
|
|
Four key process variables to autoclaving?
|
1. Temp
2. Pressure 3. Time, soak time, ramp rates 4. Vacuum |
|
|
Four kinds of autoclave gases you can use.
|
1. Nitrogen
2. Compressed Air 3. Carbon Dioxide 4. Argon |
|
|
Three methods of heating the clave.
|
1. Elec
2. Nat. gas 3. Steam |
|
|
Why is temperature a critical variable?
|
- Need uniform temperatur
- circulation system - Consider shadowing. |
|
|
Why would you use Nitrogen in an autoclave?
|
+ Abundant
+ Non-toxic + Relatively inert + Inexpensive |
|
|
Why would you use compressed air?
|
Least expensive
|
|
|
Why is compressed air dangerous to use?
|
Flammable (Contains oxygen)
|
|
|
Drawbacks to using carbon dioxide?
|
$>N2
Heavier then air, can collect in pockets |
|
|
Why use argon?
|
Very inert
Extreme conditions |
|
|
Six things you want done in an autoclave.
|
1. Void elimination
2. Conformance to tooling 3. Remove excess resin 4. Solvent removal 5. Fiber wet-out 6. Cure resin |
|
|
What is debulking
|
Every 3-5 plies of pre-preg, apply a vacuum bag and draw vacuum. Removes traped air.
|
|
|
Minimum Viscosity
|
The lowest viscosity the resin achieves during course of cure cycle
|
