1. matrix 2. reinforcement

The material that bonds the fibers together and distributes the stress evenly to the fiber “typically the matrix is the resin” is a resin system!

1. the material that adds the strength and stiffness “Is the actual material or fiber” ex. Fiberglass, carbon etc

the separation of plies due to adhesive failure

the separation of a bond from 1 structure to another “The separation between plies and the core structure”

1. negligible 2. repairable 3. non-repairable

1) Repair time and cost 2) Location 3) Complexity of repair 4) Repair weight limitations 5) Availability of repair equipment and materials 6) Spare part availability 7) technical data

Damage Assessment – “is the intermediate stage between inspection and repair” Damage Evaluation -?

57

airworthiness directive “AD”

53

Counterbore – a drilled hole that has a flat-bottomed enlargement at it’s mouth

1. Using a template, tooling and molds will increase accuracy and consistency 2. As well as using a router for accurate clean cuts

Herringbone – 1. best used to cut aramid fibers 2. the flute changes direction to cut off the pulled fiber 3. gives a clean cut 4. Reduces excess fuzzing

1. Delamination’s 2. Fractures/break outs 3. Separation

1. Film Adhesive: Structural adhesives that are thin films supported on a release paper stored in refrigerated conditions. Assist in bond line thickness bond with core 2. Foam Adhesive: “Are used to splice pieces of honeycomb together in a sandwich construction Also used to bond repair plugs to existing core during a prepreg repair” used to fill gaps

Film Adhesive: Structural adhesives that are “thin films” supported on a release paper 1.stored in refrigerated conditions. 2. Assist in bond line thickness

Foam Adhesive: 1. Are used to splice pieces of honeycomb together in a sandwich construction 2. Also used to bond repair plugs to existing core during a prepreg repair

“Brad Point drill bit” – 1. has a c-shaped cutting edge to pull the fiber out and cut it without stretching 2. Light pressure high speed 3. No cutting fluid

A defect on the outer surface that does not involve damage to the structural reinforcing fibers. ex. “Chips/scratches during handling”

1. Refer to the drying cycles specified in repair manuals and guidelines 2. Typically done with a heat blanket and vacuum bag or an oven, using the heat to convert the moisture to steam and the vacuum to draw it out

1. Fiber reinforced abrasive wheel 2. Steel wheel with a diamond-grit coated edge

1) 5052 – Alloy 2) ¼ - Cell Size 3) .500 – Wall thickness (0.0001in increments) 4) 4.3 – Density 5) N – non perforated 6) 15 – wall thickness

1. alloy 2. cell size 3. wall thickness 4. density 5. non perforated 6. wall thickness

1. Hexagonal Honeycomb Core 2. Over expanded honeycomb Core 3. Flexible Core 4. Tube Core

aramid fibre / Kevlar

exothermic reaction

​a) Epoxy

A stage – an early stage, in which the material is still soluble and fusible ​​Has been mixed but the chemical reaction has not started

1. an early stage, in which the material is still soluble and fusible ​​2. Has been mixed but the chemical reaction has not started

1. an intermediate stage, in which the material melts when heated an dissolves in certain solvents 2. Chemical reaction has started “Pre-pregs are in B stage”

1. the final stage of the curing, in which the material has become infusible and insoluble 2. The resin is fully cured

1. Hardener – used to promote or control the curing action ​ 2. Catalyst – a substance which initiates a chemical reaction

Threads running from one end of a roll of fabric to another “length of the roll”

Threads that run perpendicular to the warp direction

1. fill 2. woof

“A fabric/tape or laminate with all the major fibers running in one direction, giving strength in that direction” 1. Threads run only in the warp direction 2. Creates a smoother surface

** Unit of measurement ** “Denier is a UNIT OF MEASUREMENT that expresses fiber thickness of individual threads or filaments in fabric or textiles”

a) Orientation of ply’s ​b) Warp direction of uni-tape ​c) Ability to drape around a part ​d) Unit of measurement

a single strand goes over seven under 1 (most popular)

a pattern in which the warp and fill fibers alternate 1 over, 1 under

over three, under one

Taper (Scarfing): “is machined through the composite structure to expose each layer along a gently angled slope” 1. Loads are transferred directly through the edges of the repair plies Step Scarfing: “each damaged layer is removed in steps to provide a landing for each replacement layer” 1. Each repair ply overlaps the corresponding exposed layer in the structure 2. Uniform shear stress distribution through a tapered scarf joint

True “Lap Joint – a joint made by placing one ply partly over another and bonding the overlapped portion”

Partial (Minor) Replacement – used on honeycomb up to 0.5in Damaged honeycomb can be left in or removed and is filled with a potting compound to restore SOME strength but does restore it fully “don’t have to remove the whole core” Full Core Replacement – Damaged core must be cut out and surrounding areas must be inspected for further disbond/delam and moisture New core must be of same type, class, and grade as the original core (Wet layup) put plies of fiberglass on either side of replacement core and use potting compound around new core (Pre preg) cut pieces of ilm adhesive to bond laminates to either side of the plug and use foaming adhesives to fill around the plug

the way the honey comb core can be separated

a substance applied to two mating surfaces to bond them together by surface attachment

1. thermoplastics 2. thermosets

6.1 = density 1/8 cell size inches 15 wall thickness N = non perforated P = perforated 5052 = alloy