GATE 2024 Mechanical Engineering: Important basic concepts in Machine Design for GATE 2019 Part-1

This post gives some of the important basic concepts in Machine design (Design of Machine Elements) which can be helpful in GATE 2015 exam

In the majority of machine members, the damping capacity of the material should be zero.
At quite low temperatures (say -75°c) the notched bar impact value of steel decreases significantly.
The crest diameter of a screw thread is same as major diameter.
If d is the diameter of bolt hole then for a flanged pipe joint to be leak proof, the circumferential pitch of the bolts should be 20√d - 30√d.
Muntz metal contains copper-zinc.
A Babbitt is antimony bearing lead or tin alloy.
Steel balls for ball bearing are manufactured by cold heading.
The blow-off pressure of a safety value is 106% of boiler working pressure.
A foundation bolt with a circular end is secured to the floor by means of a steel cotter. If the pull on the bolt is 14000 kg, the diameter of the bolt should be 60 mm.
In case knuckle joint the pin is most likely to fail in double shear.
The key is cut is both shaft and hub is the case of the sunk key.
Splines are used when axial relative motion between shaft and hub is necessary.
Splined shafts are generally used in automobiles.
Universal coupling/Hook’s joint is used for non-collinear shafts.
In flange coupling, the weakest element should be key.
Turnbuckle has left-hand threads on one end and right-hand threads on another end.
The elastic nut is a locking device that has hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip.
Treating the weld as a line, the moment of inertia about the center of gravity of a circular weld of diameter d, would be πd³/4.
A single ply leather belt running at a belt velocity of 300 ft/min is likely to transmit per inch of width 4.0 HP.