Sheet Metal and Non Metallic Structures Flashcards
A well-designed rivet joint will subject the rivets to
Shear loads
A main difference between Lockbolt/Huckbolt tension and shear fasteners (other than their application)
is in the
Number of locking collar grooves
Alloy 2117 rivets are heat treated
By the manufacturer and do not require heat treatment before being driven
The general rule for finding the proper rivet diameter is
Three times the thickness of the thickest sheet
The shop head of a rivet should be
One and one- half times the diameter of the rivet shank
One of the main advantages of Hi-Lok type fasteners over earlier generations is that
They can be installed with ordinary hand tools
The markings on the head of a Dzus fastener identify the
Body diameter ,type of head, and length of the fastener
The markings on the head of a Dzus fastener identify the
Body diameter ,type of head, and length of the fastener
The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud diameter is measured in
Sixteenths of an inch
Threaded rivets (Rivnuts) are commonly used to
Attach parts or components with screws to sheet metal
The installation of Cherrymax and Olympic-Lok rivets is accomplished by utilizing
a pulling tool
Hole filling fasteners (for example, MS20470 rivets) should not be used in composite structures primarily
because of the
Possibility of causing delamination
Metal fasteners used with carbon/graphite composite structures
Must constructed of material such as titanium or corrosion resistant steel
Sandwich panels made of metal honeycomb construction are used on modern aircraft because this type
of construction
Has a high strength to weight ratio
(1) When performing a ring (coin tap) test on composite structures, a change in sound may be due to
damage or to transition to a different internal structure.
(2) The extent of separation damage in composite structures is most accurately measured by a ring (coin
tap) test.
Regarding the above statements,
Only no. 1 is true
Which of these methods may be used to inspect fiberglass/honeycomb structures for entrapped water?
1. Acoustic emission monitoring.
2. X-ray.
3. Backlighting.
2 and 3
When balsa wood is used to replace a damaged honeycomb core, the plug should be cut so that
Grain is perpendicular to the skin
When repairing puncture-type damage of a metal faced laminated honeycomb panel, the edges of the
doubler should be tapered to
100 times the thickness of the metal
One of the best ways to assure that a properly prepared batch of matrix resin has been achieved is to
Have mixed enough for a test sample
Composite inspections conducted by means of acoustic emission monitoring
By Picking up the ‘noise’ of any deterioration that may be present
What precaution, if any, should be taken to prevent corrosion inside a repaired metal honeycomb
structure?
Prime the repair with corrosion inhibitor and seal from the atmosphere
One method of inspecting a laminated fiberglass structure that has been subjected to damage is to
Strip the damage area of all paint and shine a strong light through the structure
When inspecting a composite panel using the ring test/tapping method, a dull thud may indicate
Separation of the laminate
How many of the following are benefits of using microballoons when making repairs to laminated
honeycomb panels?
1. Greater concentrations of resin in edges and corners.
2. Improved strength to weight ratio.
3. Less density
4. Lower stress concentrations
2,3 and 4
The length of time that a catalyzed resin will remain in a workable state is called the
Pot life
A category of plastic material that is capable of softening or flowing when reheated is described as a
Thermoplastic
The classification for high tensile strength fiberglass used in aircraft structures is
S - glass
Which is an identifying characteristic of acrylic plastics?
Zinc chloride with no effect
Superficial scars, scratches, surface abrasion, or rain erosion on fiberglass laminates can generally be
repaired by applying
One or more coats of suitable resin ( room temperature catalyzed ) to the surface
The classification for fiberglass reinforcement material that has high resistivity and is the most common
is
E - glass
A potted compound repair on honeycomb can usually be made on damages less than
1 inch in diameter
Composite fabric material is considered to be the strongest in what direction?
Warp
hat reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric?
Warp clock (compass)
The strength and stiffness of a properly constructed composite buildup depends primarily on
The orientation of the plies to the load direction
Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best
for strength?
60:40
What is the material layer used within the vacuum bag pressure system to absorb excess resin during
curing called?
Bleeder
Proper pre-preg composite lay-up curing is generally accomplished by
1. applying external heat.
2. room temperature exposure.
3. adding a catalyst or curing
4. applying pressure.
1 and 4
When repairing large, flat surfaces with polyester resins, warping of the surface is likely to occur. One
method of reducing the amount of warpage is to
Use short strip fiberglass in the bonded repair
When making repairs to fiberglass, cleaning of the area to be repaired is essential for a good bond. The
final cleaning should be made using
MEK (methyl ethyl ketone)
When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?
Water only
Fiberglass damage that extends completely through a laminated sandwich structure
Maybe repaired
Fiberglass laminate damage that extends completely through one facing and into the core
Requires the replacement of the damaged core and facing
Repairing advanced composites using materials and techniques traditionally used for fiberglass repairs is
likely to result in
An unairworthy repair
The preferred way to make permanent repairs on composites is by
Laminating an new repair plies
Which of the following, when added to wet resins, provide strength for the repair of damaged fastener
holes in composite panels?
1. Microballoons.
2. Flox.
3. Chopped fibers.
2 and 3
The part of a replacement honeycomb core that must line up with the adjacent original is the
Ribbon direction
Which of the following are generally characteristic of aramid fiber (Kevlar) composites?
1. High tensile strength.
2. Flexibility.
3. Stiffness.
4. Corrosive effect in contact with aluminum.
5. Ability to conduct electricity.
1 and 2
Which of the following are generally characteristic of carbon/graphite fiber composites?
1. Flexibility.
2. Stiffness.
3. High compressive strength.
4. Corrosive effect in contact with aluminum.
5. Ability to conduct electricity.
2,3 and 4
If an aircraft’s transparent plastic enclosures exhibit fine cracks which may extend in a network over or
under the surface or through the plastic, the plastic is said to be
Crazing
When installing transparent plastic enclosures which are retained by bolts extending through the plastic
material and self-locking nuts, the nuts should be
Tightened to a firm fit, then backed off one full turn
If a new safety belt is to be installed in an aircraft, the belt must conform to the strength requirements
in which document?
TSO C22
Which is considered good practice concerning the installation of acrylic plastics?
When rivets are used, adequate spacer or other satisfactory means to prevent excessive tightening
of the frame to the plastic should be provided
The coefficient of expansion of most plastic enclosure materials is
Greater than both steel and aluminum
If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces
should be
Covered with a thin coat of wax