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
Which cure condition is typically required for a prepreg composite repair to achieve design strength?
Answer: Elevated temperature cure (typically 250°F or 350°F) with applied pressure
Prepreg systems are formulated to cure at specific elevated temperatures (250°F or 350°F) under pressure to achieve full cross-linking and consolidation.
What is the function of a release film in composite repair vacuum bagging?
Answer: To prevent the vacuum bag and breather from bonding to the repair surface
Release film (such as FEP or perforated release ply) prevents the breather, bleeder, or bag material from adhering to the curing composite part.
Honeycomb core damage repair typically requires restoring core density primarily to:
Answer: Maintain the compressive and shear strength the core provides to the sandwich panel
Honeycomb core transfers shear loads between face sheets and provides compressive stability; restoring equivalent density/cell size is essential for structural integrity.
When drilling holes in a carbon fiber composite for fasteners, which drill bit type is preferred?
Answer: Carbide-tipped or solid carbide drill bit
Carbon fiber is highly abrasive and rapidly dulls HSS bits; carbide tooling maintains a sharp edge long enough to produce clean, delamination-free holes.
When wet layup repair fabric must be stored before use, the recommended method is:
Answer: Store refrigerated in a sealed container and use before the manufacturer's out-life limit
Even dry fabric should be kept clean and dry, but pre-wetted or pre-mixed materials must be refrigerated and tracked for out-life to prevent premature resin advancement.
The glass transition temperature (Tg) of a cured composite resin is important because:
Answer: Above Tg, the resin softens significantly and loses stiffness and strength
The glass transition temperature is the point above which an amorphous polymer transitions from a rigid glassy state to a rubbery state, causing a dramatic drop in structural properties.
What is the purpose of performing a porosity check (resin content test) on a wet layup repair sample panel?
Answer: To ensure the fiber-to-resin ratio meets structural requirements and voids are minimal
A porosity or resin content check verifies that the repair has the correct fiber volume fraction and void content to meet the structural properties assumed in repair design.