In order to design and manufacture a bolt possessing uniform strength throughout____________________?
Show answer Hide answer
Answer: C. drill an axial hole through head up to threaded portion so that shank area is equal to root area of thread
Explanation
Drilling an axial hole through the head and shank down to the threads reduces shank cross-sectional area. Making the unthreaded shank cross-sectional area equal to the thread root area balances bolt compliance. This geometric modification ensures that impact energy distributes uniformly along the entire fastener length. Standard bolts concentrate elastic deformation within the smaller threaded root area during tensioning. Bolts of uniform strength prevent stress concentration fatigue failures under severe dynamic shock loads. Reducing shank diameter matches its stiffness to the effective stiffness of the threaded section.
Connecting rod bolts in high-performance engines utilize reduced shank diameters to survive extreme cyclic loads. Aerospace structural fasteners feature customized shank geometries to optimize fatigue life and joint integrity. Precision engineering standards specify uniform strength bolts for critical joints subject to heavy vibrations. Increasing shank diameter increases stiffness, concentrating stress in the weaker threaded root area. Increasing bolt length alters overall compliance but does not equalize cross-sectional stress distribution. Proper tightening torque ensures correct preload but cannot correct inherent cross-sectional area mismatches.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. During endurance limit testing, a material is subjected to_______________________?
Show answer Hide answer
Answer: E. completely reversed load
Endurance limit testing subjects the material test specimen to a completely reversed cyclic load. The applied stress alternates evenly between equal maximum tension and maximum compression values. This symmetrical cyclic...
Q2. To ensure standard coarse-threaded nuts possess equal shear failure resistance compared to bolt tensile strength, the nut height (h) should roughly equal________________?
Show answer Hide answer
Answer: A. 0.4 times
To match shear failure resistance to bolt tensile strength, standard coarse-threaded nut height is typically designed around 0.8 times the bolt diameter.
Q3. The primary purpose of a gear box is___________________?
Show answer Hide answer
Answer: C. to obtain variable speeds
The primary operational purpose of a gearbox in mechanical drive systems is to obtain variable speeds. By engaging different gear ratio combinations, a gearbox allows output shaft speed to change relative to input speed....
Q4. If an individual spring is severed into two separate pieces, the stiffness rating for each resulting spring will be _________________?
Show answer Hide answer
Answer: C. double
Cutting a helical spring into two halves halves its total number of active coils. Spring stiffness is inversely proportional to the number of active coils in the spring. Halving the active coils therefore doubles the res...
Q5. In ordinary cross-laid wire ropes_________________?
Show answer Hide answer
Answer: A. direction of twist of wires in strands is opposite to the direction of twist of strands
In ordinary cross-laid wire ropes, the direction of twist of wires in strands opposes the strand twist. This opposing twist prevents the wire rope from unravelling under tension during operation. Cross-laying provides st...
Q6. Lubricating oil in a journal bearing must be introduced directly at the location where the applied load is________________?
Show answer Hide answer
Answer: A. nil or lightest
Lubricating oil in a journal bearing must be introduced directly at the location where the applied load is lightest. Introducing oil at the point of minimum pressure allows the lubricant to enter easily without fighting...