Master of Engineering Machine Design Flashcards
7 cards from real ME or MEng Master of Engineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Master of Engineering Machine Design flashcards as text
A shaft experiences a bending moment of 500 N·m and a torque of 300 N·m. Using the von Mises criterion, what is the equivalent bending moment?
Answer: 583 N·m
The equivalent moment by von Mises is √(M² + 0.75T²) = √(500² + 0.75×300²) ≈ 583 N·m.
In a bolted joint subjected to an external tensile load, the joint stiffness constant C is defined as:
Answer: kb/(kb + km)
C = kb/(kb + km) represents the fraction of external load carried by the bolt, where kb is bolt stiffness and km is member stiffness.
Which failure theory is most appropriate for designing ductile machine components under static loading?
Answer: Von Mises (Distortion Energy) Theory
The Distortion Energy Theory (von Mises) best predicts yielding in ductile materials and is the most accurate for static loading.
A helical compression spring has a spring index C = 8. What is the Wahl correction factor (approximately)?
Answer: 1.18
The Wahl factor Kw = (4C−1)/(4C−4) + 0.615/C = (31)/(28) + 0.077 ≈ 1.18 for C = 8.
In gear design, the AGMA service factor Ks accounts for:
Answer: Size effects on material strength
The AGMA size factor Ks reflects the reduction in material strength with increasing tooth and gear size.
A key connecting a shaft to a hub fails in shear. If the key has width w, length L, and the shaft radius is r, the shear stress is:
Answer: T/(r·w·L)
Shear stress τ = F/(w·L) = T/(r·w·L), where F = T/r is the tangential force on the key.
The Soderberg fatigue criterion is more conservative than the Goodman criterion because it:
Answer: Uses yield strength instead of ultimate strength as the mean stress limit
Soderberg uses Sy (yield strength) as the mean stress boundary, making it more conservative than Goodman which uses Su (ultimate strength).