Aircraft Structures and Materials Flashcards

What type of stress acts along the longitudinal axis of a structural member, tending to pull it apart?

Answer: Tensile stress

Tensile stress acts along the longitudinal axis and tends to elongate or pull a structural member apart.

Which heat treatment process is used to relieve internal stresses in aluminum alloys after machining without significantly reducing hardness?

Answer: Stress relieving anneal

Stress relieving anneal uses low temperatures to reduce residual stresses without substantially changing hardness.

What is the purpose of a doubler plate installed on an aircraft skin?

Answer: To reinforce a weakened or repaired area

A doubler plate is bonded or riveted over a repaired or weakened skin area to restore structural strength.

In a semi-monocoque fuselage, which members carry the primary bending loads?

Answer: Stringers and longerons

Stringers and longerons run longitudinally and carry the primary bending and tension/compression loads in a semi-monocoque structure.

Which material property describes resistance to scratching and surface wear?

Answer: Hardness

Hardness is the material property that indicates resistance to surface indentation, scratching, and wear.

What does the designation '2024-T4' indicate about an aluminum alloy?

Answer: It is a 2000-series alloy in the solution heat-treated and naturally aged temper

2024 identifies it as a copper-based aluminum alloy; T4 means it was solution heat-treated and naturally aged.

Which type of composite fiber offers the highest stiffness-to-weight ratio commonly used in aircraft primary structures?

Answer: Carbon/graphite fiber

Carbon/graphite fiber provides the highest stiffness-to-weight ratio of commonly used composite fibers in primary aircraft structures.