The nature of stress concentration under cyclic loading is____________________?
Show answer Hide answer
Answer: C. equally serious in both types of materials
Explanation
Stress concentrations create localized high-stress zones around geometric discontinuities like holes, notches, and fillets. Under cyclic fatigue loading, these stress spikes initiate microscopic cracks in both ductile and brittle materials. Consequently, stress concentration factors reduce fatigue strength equally seriously across both material types. Geometric changes in machine parts disrupt smooth stress flow lines, raising local stresses above nominal calculations. Ductile materials deform plastically under static loads to relieve stress concentrations, but this relief fails under fatigue. Fatigue failure is progressive, making stress concentration notches dangerous regardless of whether the material is ductile or brittle.
Stating that stress concentration is more serious in brittle materials ignores its destructive impact on ductile fatigue strength. Claiming it is more serious in ductile materials contradicts the reality that cyclic notch sensitivity affects both groups equally. Suggesting seriousness depends on other factors overlooks the universal danger of geometric stress raisers under cyclic loading.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. The detrimental effects of stress concentration under static loading conditions are most prominent in__________________?
Show answer Hide answer
Answer: B. brittle materials
Brittle materials lack the capacity for microscopic plastic yielding around sharp notch tips. Stress concentrations create severe localized stress spikes that easily trigger brittle crack propagation. Static loads exacer...
Q2. In a standard V-belt transmission, the belt makes physical contact with______________?
Show answer Hide answer
Answer: B. at sides only
Standard V-belts transmit torque through wedging action by making physical contact exclusively along their sloping sides. The bottom of the belt must remain completely clear to prevent destructive friction against the sh...
Q3. Industrial rivets are normally specified according to_______________?
Show answer Hide answer
Answer: D. nominal diameter
Industrial rivets are normally specified and designated according to the nominal diameter of their shank. The shank diameter determines the hole size required and the shear strength of the joint. Standard sizing charts e...
Q4. The spring index is expressed as___________________?
Show answer Hide answer
Answer: A. ratio of coil diameter to wire diameter
The spring index is defined mathematically as the ratio of mean coil diameter to wire diameter. This dimensionless geometric parameter helps evaluate the manufacturability of helical coil springs. Dividing the coil diame...
Q5. A taper is provided on both the cotter and its corresponding slot in order to_________________?
Show answer Hide answer
Answer: B. on one side only
Cotters and their mating slots are tapered on only one side to ensure uniform parallel alignment of connected components. A single-side taper prevents any lateral displacement or angular misalignment of the joined shafts...
Q6. If a riveted joint exhibits a tearing efficiency of 75%, the ratio of the rivet diameter to the pitch must be___________________?
Show answer Hide answer
Answer: B. 0.25
Tearing efficiency of a riveted joint is calculated as pitch minus rivet diameter divided by pitch. Setting this efficiency equation equal to 0.75 yields a diameter-to-pitch ratio of 0.25. Mathematical rearrangement of t...