Estructuras compuestas 2do 30%

One of the best ways to assure that a properly prepared batch of matrix resin has been achieved is to. perform a chemical composition analysis. have mixed enought for a test sample. test the viscosity of the resin immediately after mixing.

How does acoustic emission testing detect defects in composite materials?. by picking up the noise of any deterioration that may present. by analyzing ultrasonic signals transmited into the parts being inspected. by creating sonogram pictures of the areasbeing inspected.

What precaution, if any, should be taken to prevent corrosion inside a repaired metal honeycomb structure?. prime the repair with a corrosion inhibitor and seal from the atmosphere. paint the outside areas with several coats of exterior paint. none hoeycomb is usually made from a man-made or fibrous material wich is not suseptible to corrosion.

One method of inspecting a laminated fiberglass structure that has been subjected to damage is to. strip the damaged area of all paint and shine a strong light throught the structure. use dye-penetrant ispection procedures exposing the entire damaged area to the penetrant solution. use an eddy-current probe on both sides of the damaged area.

When inspecting a composite panel using the ring test/tapping method, a dull thud may indicate. less than full strength curing of the matrix. separation of the laminates. an area of too much matrix between fiber layers.

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. 2,3and 4. 1,2 and 4. all of the above.

The length of time that a catalyzed resin will remain in a workable state is called the. pot life. shelf life. service life.

A category of plastic material that is capable of softening or flowing when reheated is described as a. thermoplastic. thermocure. thermoset.

The classification for high tensile strength fiberglass used in aircraft structures is. E Glass. S Glass. G Glass.

Which is an identifying characteristic of acrylic plastics?. Zinc chloride will have no effect. acrylic has a yellowish tint when viewed from the edge. acetone will not soften plstic but will change its color.

Superficial scars, scratches, surface abrasion, or rain erosion on fiberglass laminates can generally be repaired by applying. a piece of resin-impregnated glass fabric facing. one or more coats of situable resin (room temperature catalyzed) to the surface. a sheet of polyethylene over the abraded surface and one or more coats of resinscured with infrared heat lamps.

The classification for fiberglass reinforcement material that has high resistivity and is the most common is. S glass. E glass. G glass.

A potted compound repair on honeycomb can usually be made on damages less than. 4 inches in diameter. 2 inches in diameter. 1 inches in diameter.

Composite fabric material is considered to be the strongest in what direction?. Fill. Warp. Bias.

What reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric?. fill clock (or compass). bias clock (or compass). warp clock (or compass).

The strength and stiffness of a properly constructed composite buildup depends primarily on. a 60 percent matrix to 40 percent fyber ratio. the orientation of the plies to the load direction. the ability of the fibers to transffer stress to the matix.

Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best for strength?. 40:60. 50:50. 60:40.

What is the material layer used within the vacuum bag pressure system to absorb excess resin during curing called?. bleeder. breather. release.

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 agent to the resin. 4. applying pressure. 2 and 3. 1 and 4. 1,3 and 4.

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 (Methil ethil ketone). Soap, water and scrub brush. A thixotropic agent.

When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?. water soluble oil. water displacing oil. Water only.

Fiberglass laminate damage not exceeding the first layer or ply can be repaired by. filly with a putty consisting of a compatible resin and clean short glass fibers. sanding the damaged area until aerodynamic smothness is obtained. trimming the rough edges and sealing with paint.

Fiberglass damage that extends completely through a laminated sandwich structure. may be repaired. must be filled with resin to eliminate dangerous stress concentrations. may be filled with putty wich is compatible with resin.

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. add an extra amount of catalist to the resin. use short strips of fiber glass in the bonded repair.

Fiberglass laminate damage that extends completely through one facing and into the core. cannot be repaired. requires the replacement of the damaged core and facing. can be repaired by using a typical metal facing patch.

Repairing advanced composites using materials and techniques traditionally used for fiberglass repairs is likely to result in. restored strengh and flexibility. improved wear resistance to the structure. an unairworthy repair.

The preferred way to make permanent repairs on composites is by. bonding on metal or cured composite patches. riveting on metal or cured composite patches. laminating on 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. 1 and 3. 1,2 and 3.

The part of a replacement honeycomb core that must line up with the adjacent original is the. cell side. ribbon direction. cell edge.

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. 1,3 and 4. 1,3 and 5.

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. 1 and 3. 2, 3 and 4. 1, 3 and 5.

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. hazing. brinelling. 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 plus one full turn. tightened to a firm fit then backed off one full turn. tightened to a firm fit.

If a new safety belt is to be installed in an aircraft, the belt must conform to the strength requirements in which document?. STC 1282. 14 CFR part 39. TSO C22.

Which is considered good practice concerning the installation of acrylic plastics?. When nuts and bolts are used, the plastic should be installed hot and tightened to a firm fit before the plastic cools. when rivets are used adecuate spacer of other satisfactory means to prevent excesive tightening of the frame to the plastic should be provided. when rivet and nuts or bolts are used sloted holes are not recommended.

The coefficient of expansion of most plastic enclosure materials is. greather than both steel and aluminium. greather than steel but less than aluminium. less thah either steel or aluminium.

If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be. polished with rubbing compound applied wiyh a damp cloth. buffed with a clean, soft,dry cloth. covered with a thin coat of wax.

Cabin upholstery materials installed in current standard category airplanes must. be fireproof. be at least flame resistand. meet the requirements prescribed in part 43.

What is the most common method of cementing transparent plastics?. heat method. soak method. bevel method.

What type of bit should be used to drill holes in Plexiglas?. a standart twist drill. a specially modified twist drill. a dulled twist drill.

What is the purpose of a gusset or gusset plate used in the construction and repair of aircraft structures?. to hold structural menbers in position temporarily until the permanent atachment has been completed. to provide acces for inspection of structural atachements. to joint and reinforce inserting structural members.

An aircraft stmcture that carries most of the aerodynamic stresses in its outer skin is called a/an _____________ structure. aeroelastic taiIoring. aerodynamic taiIoring.

The glass fibers that produce the stronger structure are made of _________ -glass. S. E.

Kevlar fabric is noted for being _____________. flexible. stiff.

Graphite fabric is noted for being _____________. flexible. stiff.

Corrosion can be a problem with aluminum alloys when they are bonded to_________. fiberglass. graphite.

The type of plastic material that is softened by heat and that regains its hardness when it is cooled is a ___________ material. thermoplastic. thermosetting.

Polyester resins ____________ used as a matrix material for modern high-strength composite structures. are. are not.

There ____________ more than one type of epoxy resin. is not. is.

Prepregs are prevented from curing before they are used by storage in a/an ____________ . REFIGERATOR. HEATER.

Film-type adhesives _ ___________ need to be stored in a refrigerator to extend their shelf life. do. do not.

The adhesive recommended to bond a plug of honeycomb material into a honeycomb panel is a/an ____________ adhesive. foaming. rubbing.

A block of Styrofoam to be used as the form for an aircraft component __________ be cut with a hot-wire cutter. cannot. can.

Urethane foam ____________ be used with a polyester resin. can. cannot.

Three ways heat and pressure can be applied to composite component are: a. matched dies b. vacuum bag c. autoclave. a. matched dies b. vacuum bag c. stress .

The simplest method to check a piece of composite structure for possible delamination damage is to tap the suspected area with the edge of a/an ___________. coin. sheet.

A method of nondestructive inspection used to check a piece of composite structure for crack damage is a/an_____________inspection. ultrasonic. ultraviolet light.

Water inside a honeycomb core can be detected by using ______________ inspection. radiographic. ultrasonic.

The fini sh on a piece of composite structure to be repaired may be properly removed with ____________. paint stripper. sandpaper.

After the damage has been removed from a piece of honeycomb-core composite material, all of the sanding dust should be removed with ___________ air. compressed. vacuum.

When installing the replacement plug in a piece of honeycomb core, it is important that the length or __________ direction of the plug be the same as that of the structure. ribbon. contrary.

When drilling cured composite materials, the drill should be turned __________. fast. slow.

One of the biggest differences in working aluminum and acrylic plastics lies in the _________ heat conduction of the acrylic. poorer. better.

Acetone ____________ soften acrylic plastic. does not. does.

The preferable way to store fl at sheets of acryli c plastic is ____________. horizontal. vertical.

When a piece of acrylic plastic is cut on a band saw to the approximate outline of the part, the finaltrim can be made with a/an ___________. sander. lime.

When drilling acrylic plastics, the drill should be turned ____________. fast. slow.

Small pieces of acrylic plastic can be heated for forming in a/an ___________ bath. water. oil.

Two chemicals that can be used as a solvent for acrylic plastic are: a. methylene chloride b. ethylene dichloride. a. methylene chloride b. zinc chromate.

A C-clamp __________ recommended for holding pressure on an acrylic plastic material while it is being cemented. is. is not.

The best type of clamp to use to apply pressure when cementing two pieces of acrylic plastic togetheris a/an ____________clamp. spring. rigid.

The best method of removing dirt from a plastic windshield is by flushing it with ______________________ . fresh water. whinshiel cleaner.

Oil and grease can be removed from acrylic plastic with a _______________________ solution. soap and water. hipochloride.

After cleaning a windshield, it should be coated with a good grade of ____. wax. oil.

The window of a pressurized aircraft can be checked for thickness with a/an _____________ thickness measuring instrument. ultrasonic. ultrared.

Crazing can be removed from an acrylic windshield with _________. abrasives. detergent.

hen removing scratches from a windshield with sandpaper, the paper should be moved in a ___________ motion. straight. circular.

A patch cemented over a hole or crack should extend for _____________ inch beyond the damage. 3/4. 4/3.