Q.1
In the calculation of induced shear stress in helical springs, the Wahl's stress factor is used to take care of
  • Combined effect of transverse shear stress and bending stress in the wire
  • Combined effect of bending stress and curvature of the wire
  • Combined effect of transverse shear stress and curvature of wire
  • Combined effect of torsional shear stress and transverse shear stress in the wire
Q.2
Stress concentration factor is defined as the ratio of
  • Maximum stress to the endurance limit
  • Nominal stress to the endurance limit
  • Maximum stress to the nominal stress
  • Nominal stress to the maximum stress
Q.3
If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation
  • 124 d
  • 138 d
  • 151 d
  • 168 d
Q.4
Which is correct statement? Stress concentration in cyclic loading is
  • Very serious in brittle materials and less serious in ductile materials
  • Very serious in ductile materials and less serious in brittle materials
  • Equally serious in both types of materials
  • Seriousness would depend on other factors
Q.5
Which of the following statement is correct, for two shafts connected in parallel?
  • Torque in each shaft is the same
  • Shear stress in each shaft is the same
  • Angle of twist of each shaft is the same
  • Torsional stiffness of each shaft is the same
Q.6
The value of stress concentration factor depends upon
  • Material and geometry of the part
  • Geometry of the part
  • Material of the part
  • None of these
Q.7
Cold working
  • Increases the fatigue strength
  • Decreases the fatigue strength
  • Has no influence on fatigue strength
  • Alone has no influence on fatigue strength
Q.8
At low temperatures (say 75°C) the notched bar impact value of steel
  • Increases markedly
  • Decreases markedly
  • Remain same
  • Depends on heat treatment carried out
Q.9
While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as
  • Both the ends fixed
  • Both the ends hinged
  • One end fixed and the other end hinged
  • One end fixed and the other end free
Q.10
The shock resistance of steel is increased by adding
  • Nickel
  • Chromium
  • Nickel and chromium
  • Cobalt and molybdenum
Q.11
A closely coiled helical spring is acted upon by an axial force. The maximum shear stress developed in the spring is τ. The half of the length of the spring if cut off and the remaining spring is acted upon by the same axial force. The maximum shear stress in the spring in new condition will be
  • τ/2
  • τ
  • 2 τ
  • 4 τ
0 h : 0 m : 1 s