Composite Structures Flashcards
Benefits of composites:
Lighter weight.
Stronger.
More rigid.
Better able to withstand sonic vibrations.
Basic categories of composite materials:
Reinforcing materials.
Matrix materials.
Types of reinforcing materials:
Fiber glass. (S-glass and E-glass)
Kevlar.
Graphite/Carbon.
Ceramic.
Boron.
The major fibers in unidirectional fabric:
Warp threads.
The small cross threads in unidirectional fabric:
Fill threads
Basic types of resins used in aircraft construction:
Thermosetting.
Thermoplastic.
Basic types of thermosetting resins:
Epoxy resins.
Polyester resins.
T\F
Epoxy resin curing requires a smaller amount of catalyst than polyester resins.
False.
Epoxy resins use much more catalyst.
What prevents prepreg from curing before use?
Refrigeration.
Purpose of the matrix:
Binds reinforcing material (laminates) together and transfers stresses into them.
Most matrix material are in the form of ______.
Resins.
Basic types of foam:
Styrofoam.
Urethane foam.
What is used to cut styrofoam?
A hot wire.
What important factors must be considered when replacing a piece of honeycomb?
Use same cell size and ensure that the “ribbon direction” of the new piece matches that of the damaged area.
_______ is/are used to add body to resins.
Micro balloons
Methods of delamination detection:
Coin tap.
Ultrasonic.
Backlighting.
Acoustic emission monitoring.
X-ray.
What testing methods are used to detect water in a honeycomb?
X-ray.
Backlighting.
What type of drill is used on Kevlar?
Brad point drills.
What type of drill is used on graphite material?
Spade drill.
Tiny hair like cracks in windows and windshields:
Crazing
What determines the strength of a composite structure?
Fiber orientation.
Term for layers of composites:
Laminate.
The stretch diagonal to the thread direction is called ____.
Bias
Define shelf life:
The expiration date of the material.
The time that a resin is usable after being mixed:
Pot life.
What is the dwell time?
(Cure time) the post application wait time.
Types of fillers:
Chopped fibers (Flox)
Micro balloons.
What type of filler adds strength to the repair?
Flox. (Chopped fibers)
Two ways to prep the repair area for matrix filler:
Scarfing (sanding to a taper).
Step cut.
Order of laying the plies:
Filler ply>
Repair ply>
Sanding ply.
Methods of curing:
Room temp cure/wet lay out.
Heat bond.
