ESE ME 2018: Machine Design Achievers National Test for ESE & GATE ME Exams

Question 1

A journal bearing sustains a radial load of 3672 N. The diameter of the bearing is 50 mm and the length is 0.1 m. The diametral clearance is 0.1 mm and the shaft rotates at 50 r.p.s. If the absolute viscosity of the oil is 0.6 kg/m-s, the value of Sommerfeld number is

Question 2

In a multiple- disc clutch, the axial intensity of uniform pressure is not to exceed 0.2Mpa. The inner radius of the discs is 100mm and is half the outer radius. The axial force per pair of contact surfaces in N is

Question 3

In case of power screws, what is the combination of materials used for the screws and nut?

Question 4

Consider the following statements associated with variable loading of bolts.
1). Smaller the stiffness constant, larger will be the external load carried by the bolts.
2). Greater the pretension, lesser will be the value of the alternating load carried by the bolts.
3). In variable loading, component will variable load is more dangerous than component with static load.
4). A high value of pretension is undesirable against fatigue failure.
Which of the statements are correct?

Question 5

In designing a shaft for variable loads, the S.N. diagram can be drawn by (S_ut stands for ultimate tensile strength and S_e for the endurance limit)

Question 6

Consider the following statements regarding improvement of efficiency of worm gear drive.
1). Efficiency can be improved by increasing the spiral angle of worm thread to 45 ° or more.
2). Efficiency can be improved by adopting proper lubrication
3). Efficiency can be improved by adopting worm diameter as small as practicable to reduce sliding between worm-threads and wheel teeth.
4). Efficiency can be improved by adopting convex tooth profile both for worm and wheel.
Which of these statements are correct?

Question 7

A bumper consisting of two helical springs of circular section brings to rest a railway wagon of mass 1500 kg and moving at 1 m/s. While doing so, the springs are compressed by 150 mm. Then, the maximum force on each spring(assuming gradually increasing load) is:

Question 8

Assertion (A): In design of double welds in fillet unsymmetrical sections with plates subjected to axial loads lengths of parallel welds are made unequal.
Reason (R): The lengths of parallel welds in fillet welding of an unsymmetrical section with a plate are so proportioned that the sum of the resisting moments of welds about the Centre of gravity axis is zero.

Question 9

A compound fillet welded joint is loaded by P as shown. The maximum shearing stress occurs at point

Question 10

Consider the following joints:
1). railways carriage wheel and axle
2). IC engine cylinder and line
Which of the above joints is/are the result(s) of interference fit?