Elements of Machine Design-10

  1. Fundamentals of design
  2. Design of joints, levers and offset links
  3. Design of shafts, keys and couplings
  4. Design of power screws
  5. Design of springs
  6. Design of bolted and welded joints
  7. Selection of anti-friction bearings and gears

Design of Bolted and Welded joints

1   Setscrews are
    (A)   Similar to tap bolts except that a greater variety of shapes of heads are available
    (B)   Slotted for screw driver and generally used with a nut
    (C)   Used to prevent relative motion between parts
    (D)   Similar to studs

2   The designation M 36 x 2 means
    (A)   Metric threads of 36 mm outside diameter and 2 mm pitch
    (B)   Metric coarse threads of 36 mm outside diameter and 2 mm pitch
    (C)   Metric threads of 36 mm pitch diameter and 2 mm pitch
    (D)   Metric threads of 36 mm core diameter and 2 mm pitch

3   The designation M 20 means
    (A)   Metric coarse threads of 20 mm outside diameter
    (B)   Metric fine threads of 20 mm outside diameter
    (C)   Metric threads of 20 mm core diameter
    (D)   Metric threads of 20 mm pitch diameter

4   The largest diameter of external or internal screw thread is called
    (A)   Major diameter
    (B)   Minor diameter
    (C)   Pitch diameter
    (D)   None of the above

5   A screw is specified by
    (A)   Major diameter
    (B)   Minor diameter
    (C)   Pitch diameter
    (D)   Mean diameter

6   A washer is specified by
    (A)   Outer diameter
    (B)   Inner diameter
    (C)   Thickness
    (D)   Mean diameter

7   Machine bolts are
    (A)   Through bolts with rough shank and used with nut
    (B)   Used to prevent relative motion between two parts
    (C)   Similar to stud
    (D)   Turned into a threaded hole in one of the parts

8   The coupler of turnbuckle has
    (A)   Right hand threads on both ends
    (B)   Left hand threads on both ends
    (C)   Left hand threads on one end and right hand threads on other end
    (D)   No threads

9   Eyebolts are used
    (A)   To prevent relative motion between two parts
    (B)   To absorb shocks and vibrations
    (C)   To lift and transport machines and heavy objects on shop floor
    (D)   To prevent loosening of threads in bolted assembly

10   A stud is
    (A)   Screw with long threads
    (B)   Screw with circular head
    (C)   Screw with hexagonal head
    (D)   Headless screw with threads on both sides

11   Bolts are most suitable to carry
    (A)   Shear
    (B)   Axial tension
    (C)   Bending
    (D)   Shear and bending

12   The shock absorbing capacity of a bolt may be increased by
    (A)   Increasing its shank diameter
    (B)   Decreasing its shank diameter
    (C)   Tightening the bolt property
    (D)   Making the shank diameter equal to the core diameter of the thread

13   If core diameter of bolt is 13.8cm then its nominal diameter is given by?
    (A)   17.27mm
    (B)   15.34mm
    (C)   14.67mm
    (D)   16.34mm

14   Refer to figure. Two plates are fastened by means of two bolts. The yield strength of bolt is 400N/mm² and factor of safety is 4. Determine the permissible shear stress in the bolts.

    (A)   100N/mm²
    (B)   50N/mm²
    (C)   25N/mm²
    (D)   75N/mm²

15   Refer to figure. Two plates are fastened by means of two bolts. The yield strength of bolt is 400N/mm² and factor of safety is 4. Determine the size of the bolts.

    (A)   8mm
    (B)   9mm
    (C)   10mm
    (D)   11mm

16   The structure shown is subjected to an eccentric force P=5kN and eccentricity=500mm. The horizontal distance between two bolts is 200mm and vertical distance between bolts is 150mm. The yield strength of bolts is 400N/mm² and factor of safety is 3. Referring to figure, determine the primary shear force.

    (A)   625N
    (B)   1250N
    (C)   2500N
    (D)   1000N

17   Referring to figure, determine the secondary shear force.

    (A)   2000N
    (B)   2500N
    (C)   1500N
    (D)   5000N

18   Which of the following types is not fillet weld?
    (A)   Butt joint
    (B)   Lap joint
    (C)   T-joint
    (D)   Corner joint

19   In gas welding which of the following is generally used?
    (A)   Oxygen-Hydrogen
    (B)   Oxygen-Acetylene
    (C)   Oxygen-Hydrogen or Oxygen-Acetylene
    (D)   None of the mentioned

20   Rails in the field are generally welded by using
    (A)   Thermit welding
    (B)   Gas welding
    (C)   Electric arc welding
    (D)   Forge welding

21   Which type of joint is used if plate thickness is less than 5 mm?
    (A)   Single V butt weld
    (B)   Single U butt weld
    (C)   Square butt weld
    (D)   Double U butt weld

22   Calculate strength of the welded joint shown below, when 70 MPa is the allowable shear stress for the weld material.

    (A)   54.44 x 10^3 N
    (B)   77 x 10^3 N
    (C)   50 x 10^3 N
    (D)   None of the above

23   Transverse fillet welded joints are designed for
    (A)   Tensile strength
    (B)   Compressive strength
    (C)   Shear strength
    (D)   Bending strength

24   Steels used for welded assemblies are
    (A)   Medium carbon steel
    (B)   Mild steel
    (C)   High carbon steel
    (D)   Alloy steel

25   The weakest plane in a fillet weld is
    (A)   The throat
    (B)   Side parallel to the force
    (C)   Smaller of two sides
    (D)   Side normal to the force

26   The cross-section of a standard fillet weld is a triangle with base angle of
    (A)   45 deg and 45 deg
    (B)   60 deg and 30 deg
    (C)   50 deg and 40 deg
    (D)   20 deg and 70 deg

27   The parallel fillet welds are designed for
    (A)   Tensile strength
    (B)   Shear strength
    (C)   Bending strength
    (D)   Compressive strength

28   The size of the filled weld is given by
    (A)   Throat of fillet
    (B)   Smaller side of triangle
    (C)   Hypotenuse of triangle
    (D)   Bigger side of triangle

29   In transverse fillet welded joint, the size of weld is equal to
    (A)   0.5 x throat of weld
    (B)   Throat of weld
    (C)   2 x throat of weld
    (D)   Sqrt (2) x throat of weld

30   When mild steel components are welded, the ratio of strength of the weld material to that of the parent body is
    (A)   More than one
    (B)   Less than one
    (C)   Equal to one
    (D)   None of the three

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