lec 10 mcq Flashcards
Which of the following is NOT a common reason for structural failure?
A) Inadequate design
B) Proper curing
C) Unanticipated loads
D) Material fatigue
Answer: B
Which crystal structure is known to be characteristically brittle?
A) Face-centered cubic (FCC)
B) Hexagonal close-packed (HCP)
C) Body-centered cubic (BCC)
D) Amorphous
Answer: C
Which of the following elements has a body-centered cubic (BCC) structure?
A) Aluminum
B) Chromium
C) Nickel
D) Copper
Answer: B
Face-centered cubic (FCC) structures typically have how many atoms per unit cell?
A) 9
B) 12
C) 14
D) 16
Answer: C
Which element has an FCC structure and is ductile?
A) Titanium
B) Chromium
C) Nickel
D) Beryllium
Answer: C
What is the packing density characteristic of hexagonal close-packed (HCP) structures?
A) Lowest
B) Intermediate
C) Highest
D) Variable
Answer: C
What do small grains with long boundaries typically improve?
A) Ductility
B) Brittleness
C) Material strength
D) Corrosion
Answer: C
Fatigue often occurs due to what type of stress at a crack?
A) Shear
B) Tensile
C) Compressive
D) Torsional
Answer: B
Which condition is a key contributor to fatigue failure?
A) Static loading
B) Cyclic stress
C) Uniform pressure
D) Creep deformation
Answer: B
What is meant by “stress concentration”?
A) Spread of load over a wide area
B) Equal distribution of plastic strain
C) Localization of high plastic stress
D) None of the above
Answer: C
Which of the following affects composite performance?
A) Ply thickness
B) Curing schedule
C) Fibre orientations
D) All of the above
Answer: D
What might poor fibre matrix volume ratios lead to?
A) Improved stiffness
B) Laminate failure
C) Better load distribution
D) Fatigue resistance
Answer: B
What term describes deviations in fibre alignment within a laminate?
A) Ply shifting
B) Fibre waviness
C) Delamination
D) Creep strain
Answer: B
Which type of corrosion involves metal loss in narrow, confined spaces?
A) Galvanic
B) Pitting
C) Crevice
D) Fretting
Answer: C
Which corrosion type occurs when dissimilar metals are in contact in an electrolyte?
A) Intergranular
B) Galvanic
C) Chemical
D) Pitting
Answer: B
Which of the following is an electrochemical corrosion mechanism?
A) Creep
B) Pitting
C) Fatigue
D) Grain boundary diffusion
Answer: B
Which of the following can typically be determined from an on-site turbine engine inspection?
A) Foreign object debris ingestion
B) Engine surging
C) If the engine was on fire prior to impact
D) Control system malfunction
Answer: C
What is an indication the engine was rotating at impact?
A) Unburned fuel residue
B) Soot on components
C) Rotational scoring
D) FOD ingestion
Answer: C
Which of the following requires lab and flight data to confirm?
A) Fuel flow runaway
B) Presence of fire at impact
C) Engine was hot at impact
D) Blade separation
Answer: A
What is “core lock”?
A) Foreign object in turbine
B) Engine seizure
C) Overheating of bearings
D) Fan blade fatigue
Answer: B
Which technique is used to detect surface and near-surface defects using magnetism?
A) Radiography
B) Magnetic particle inspection
C) Ultrasonic testing
D) FTIR spectroscopy
Answer: B
Which method uses sound waves to detect internal flaws in materials?
A) Radiography
B) FTIR
C) Ultrasonic Testing (UT)
D) Optical microscopy
Answer: C
Which technique uses electromagnetic radiation to produce images of internal structures?
A) Magnetic particle inspection
B) Radiography
C) FTIR spectroscopy
D) Tensile testing
Answer: B
What is the purpose of FTIR spectroscopy in materials testing?
A) Detect chemical bonds and material composition
B) Analyze surface cracks
C) Determine tensile strength
D) Identify voids
Answer: A
What does a scanning electron microscope (SEM) offer in failure analysis?
A) Non-destructive testing
B) Low magnification surface views
C) Up to x60,000 magnification
D) Bulk material testing
Answer: C
