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
What is the purpose of a breather layer in a vacuum bag layup?
Answer: To allow air and volatiles to escape evenly across the part during cure
The breather (bleeder) layer is a porous material placed over the part to allow entrapped air and cure volatiles to flow uniformly to the vacuum port.
Carbon fiber composites must be handled with care around aluminum structure primarily because of:
Answer: Galvanic corrosion of the aluminum where carbon and aluminum are in direct contact
Carbon fiber is cathodic relative to aluminum, and direct contact in the presence of moisture creates a galvanic cell that accelerates aluminum corrosion.
Which nondestructive inspection (NDI) method is BEST suited for detecting delamination in thick composite laminates?
Answer: Ultrasonic inspection (A-scan or C-scan)
Ultrasonic inspection can penetrate through multiple plies and detect internal delaminations, voids, and disbonds that are invisible to surface methods.
In a wet layup repair, the pot life of a two-part epoxy refers to:
Answer: The time after mixing during which the resin remains usable for application
Pot life is the working time after mixing during which viscosity remains low enough to wet out fabric and achieve consolidation before the resin gels.
What is the MINIMUM ply overlap required when adding repair plies in a stepped or scarf repair per typical SRM guidance?
Answer: 1.0 inch per ply step
Most structural repair manuals require a minimum of 1 inch of overlap per stepped ply to ensure adequate load transfer from the repair patch to the original structure.
When curing a composite repair using a heat blanket, which parameter is MOST important to monitor continuously?
Answer: Cure temperature ramp rate and hold temperature at the part surface
Incorrect ramp rates can cause residual stress or incomplete cure; hold temperature must be verified at the part surface because heat blankets can overshoot.
Aramid (Kevlar) fiber composite panels present a unique machining challenge because:
Answer: Aramid fibers are tough and tend to fray or delaminate rather than cut cleanly
Aramid fibers are extremely tough and absorb energy rather than fracturing, causing fuzzing and delamination during drilling or trimming without special tooling.