Diploma 6th Sem (Mechanical Engineering)
Course Code: 601
Subject Name: Design of Machine Elements
Important Questions
Chapter-1
Q.1. Explain Various steps of general design procedure of any machine elements.
Q.2. Define factor of safety & safe design stress. Explain all types of loads.
Q.3. What is Belt, Rope, Chain, Gear. Also classify each of them.
Q.4. Define the following terms:
(a) Strength (b) Stiffness (c) Availability (d) Safety
Q.5. What is Preliminary Design.
Chapter-2
Q.1. Differentiate between cotter joint and knuckle joint. Also write the use of cotter & knuckle
joint.
Q.2. Design a knuckle joint to transmit load of 150 kN. The design stress are 75 Mpa in tension,
60 Mpa in shear and 150 Mpa in compression.
Q.3. Design a cotter joint for a load of 200 kN allowable stress in tension, shear and crushing are
80 N/mm2, 60 N/mm2 and 120 N/mm2 respectively.
Chapter-3
Q.1. What is key. Write any five type of key and also draw their neat sketch.
Q.2. Define Spring and also write its type.
Q.3. what is shaft.
Q.4. What is coupling. Also write its type with neat sketch.
Q.5. A solid shaft transmit 1.5 MW power at 300 rpm Calculate the Diameter of shaft if the
maximum torque transmitted exceeds the mean torque by 20% and maximum allowable
shear stress is not to exceeds 60 Mpa.
Q.6. Calculate the dimensions of a helical spring for a spring-loaded safety valve for the
following data: Valve dia. = 60 mm., Max. Pressure when the valve below off freely =
0.73 N/mm2, Valve lifts when pressure rises from 0.7 N/mm2 to 0.73 N/mm2, Max.
permissible stress = 500 N/mm2, spring index = 6, Modulus of rigidity = 0.85 x 105 N/mm2.
Q.7. Design a cast Iron flange coupling which transmit 8 KW power at 600 rpm. Allowable stresses
are:
Allowable shear stress for shaft, key & Bolt = 35 N/mm2σ
Crushing stress for belt & key = 60 N/mm2
Shear stress for cast Iron = 18 N/mm2
Chapter-4
Q.1. Define the Riveted joint & define its types with examples. Also write the definition of
common terms like pitch, back pitch, efficiency, Margin etc.
Q.2. Design a Double riveted lap joint with zig-zag riveting for a 16 mm. thick plate. Assume
Tensile, shear & compressive stress 100 N/mm2, 75 N/mm2 and 130 N/mm2 respectively.
State how the joint will fail, also find the efficiency of the joint.
Q.3. A double riveted double cover butt joint in plates 20 mm thick is made with 25 mm.
diameter rivets at 100 mm. pitch. The permissible stresses are:
σ σ
t = 120 Mpa τ = 100 Mpa c = 150 Mpa
Find the efficiency of joint, taking the strength of the rivet in double shear as
twice than that of single shear.
Q.4. A double riveted lap joint with zig-zag riveting is to be designed for 13 mm thick plates.
Assume:
σ σ
t = 80 Mpa τ = 60 Mpa c = 120 Mpa
State how the joint will fail and find the efficiency of the joint.
Chapter-5
Q.1. Define the Welded joint & define its types with examples. Also write the definition of
common terms related with welded joint.
Q.2. A plate 75 mm. wide and 12.5 mm. thick is joined with another plate by a single transverse
weld and a double parallel fillet weld. The maximum tensile and shear stresses are 70 Mpa
and 56 Mpa.
Find the length of each parallel fillet weld, if the joint is subjected to both
static and fatigue loading.
Q.3. A plate 100 mm. wide and 10 mm. thick is to be welded to another plate by means of double
parallel fillets. The plates are subjected to a static load of 80 kN, find the length of weld if
the permissible shear stress in the weld does not exceed 55 Mpa.
Chapter-6
Q.1. Define the term “Threads”. Also write its types.
Q.2. what is “bolts”. Also write its types.
Q.3. State and discuss various types of stress coming on screw threads.
Q.4. An eye bolt is to be used for lifting a load of 60 kN. Find the nominal diameter of the bolt, if
the tensile stress is not to be exceed 100 Mpa.
Chapter-7
Q.1. What is clutch. Also write different types of clutches.
Q.2. A single plate clutch effective on both sides is required to transmit 20 kW at 2500 rpm,
determine the outer and inner diameter of frictional surface if the coefficient of friction is
0.25, ratio of diameter is 1.5 and the maximum pressure not to exceed 0.12 N/mm2. Also
Calculate the axial load considering the case of uniform wear.
Q.3. A multiple disc clutch, steel on bronze, is to transmit 4.5 KW at 750 rpm. The inner radius
Of the contact is 40 mm. & outer radius of the contact is 70 mm. The clutch operates in oil
With an expected coefficient of 0.1. The average allowable pressure is 0.35 N/mm2. Find:
I. The total No. of steel & bronze discs
II. The actual axial force required
III. The actual average pressure
IV. The actual maximum pressure
Q.4. A multiple clutch has three disc on the driving shaft and two on the driven shaft. The inside
diameter of the contact surface is 120 mm. The maximum pressure between the surfaces is
limited to 0.1 N/mm2. Design the clutch for transmitting 25 KW at 1575 rpm. Assume
uniform wear condition and coefficient of friction as 0.3.
Chapter-8
Q.1.What is Bearing. Write down the types of rolling contact bearing, Ball bearing. Also write
the application of Bearing.
Q.2. What is Hydro Dynamic and Hydro static Bearing.
Q.3. Write the purpose of lubricants in bearing.
Q.4. Explain Summerfield Number.
Q.5. Write the bearing characteristic number.
Q.6 Enlist essential factor in bearing selection.
NOTE: All the students are requested that practice all types of numerical problems
from the exam point of view.
