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Composite Materials & Repair Flashcards

7 cards from real ACS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Composite Materials & Repair flashcards as text

  1. What is the primary purpose of a peel ply in composite layup?

    Answer: To provide a sacrificial surface layer that creates a bondable texture when removed

    Peel ply is a woven fabric applied as the last layer during layup; when peeled off after cure it leaves a clean, textured surface ready for secondary bonding.

  2. Which type of damage to a composite structure is MOST difficult to detect visually?

    Answer: Delamination beneath an intact surface skin

    Delamination (separation of plies) can exist beneath an undamaged-looking outer skin and requires tap testing or NDI methods to detect.

  3. During a tap test on a composite panel, a dull or hollow sound compared to surrounding areas indicates:

    Answer: A subsurface void, delamination, or disbond

    A dull or dead sound during tap testing indicates a loss of bond or internal void, while a solid ringing sound indicates good laminate integrity.

  4. What is the correct fiber orientation for a quasi-isotropic composite layup?

    Answer: Plies at 0°, +45°, -45°, and 90°

    A quasi-isotropic layup uses plies at 0°, +45°, -45°, and 90° to provide approximately equal stiffness and strength in all in-plane directions.

  5. When performing a scarf repair on a composite laminate, the scarf ratio is typically expressed as:

    Answer: Horizontal taper length divided by the laminate thickness

    Scarf ratio is the ratio of the taper length to the laminate thickness (e.g., 20:1 means 20 mm of taper per 1 mm of thickness), determining how gradually load is transferred.

  6. Which adhesive film storage requirement is MOST critical to maintaining its properties?

    Answer: Store refrigerated or frozen and track out-time carefully

    Adhesive films and prepregs must be stored frozen (typically at 0°F or below) to arrest curing, and out-time at room temperature must be logged and not exceeded.

  7. When removing paint before a composite repair, the preferred method over mechanical sanding is:

    Answer: Chemical paint stripper rated for composites

    Chemical strippers formulated for composites remove paint without abrading fibers or introducing heat that could damage the matrix resin.