Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 3rd Sem Old 131902 Machine Design And Industrial Drafting Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?III (Old) EXAMINATION ? WINTER 2019
Subject Code: 131902 Date: 28/11/2019
Subject Name: Machine Design & Industrial Drafting
Time: 02:30 PM TO 05:30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain hole-based and shaft based limit system with neat sketch. 07
(b) Define (1) Crushing stress (2) Preferred Number (3) Factor of Safety
(4) Residual stress (5) transverse stress (6) Static Load (7) Shock load
07
Q.2 (a) Explain different failures of riveted joint with neat sketches. 07
(b) A double riveted lap joint is made between 18 mm thick plates. The rivet diameter
and pitch are 24 mm and 72 mm respectively. If the ultimate stresses are 415
MPa in tension, 330 MPa in shear and 675 MPa in crushing, find the minimum
force per pitch which will rupture the joint. If the above joint is subjected to a
load such that the factor of safety is 4, find out the actual stresses developed in
the plates and the rivets.
07
OR
(b) A double riveted single cover butt joint in plates 22 mm thick is made with 25
mm diameter rivets at 85 mm pitch. The permissible stresses are: ?t = 100 MPa;
? = 85 MPa; ?c = 120 MPa. Find the efficiency of joint.
07
Q.3 (a) Design a socket and spigot cotter joint to support a load varying from 35 kN in
compression to 35 kN in tension. The material used is carbon steel for which the
allowable are: ?t = ?c = 55 MPa; ? = 40 MPa and crushing stress = 100 MPa. The
load is applied statically.
07
(b) Design a knuckle joint to connect two steel rods under a tensile load of 35KN.
The allowable stresses are 60MPa in tension 55MPa, in shear and 85MPa in
crushing
07
OR
Q.3 (a) Find the diameter of a solid shaft to transmit 30 kW at 230 rpm. The shear stress
is 50 MPa. If a hollow shaft is to be used in place of solid shaft, find the inside
and outside diameter when the ratio of inside to outside diameter is 6:8
07
(b) Write practical applications of shaft and axle. 07
Q.4 (a) Explain with sketch design procedure of bell crank lever 07
(b) A lever safety valve is 75 mm in diameter. It is required to blow off at 1.3 N/mm2.
Design the mild steel lever of rectangular cross-section if the permissible stresses
are 70 MPa in tension, 52.5 MPa in shear and 24.5 MPa in bearing. The pin is
made of the same material as that of the lever. The distance from the fulcrum to
the dead weight of the lever is 800 mm and the distance between the fulcrum pin
and the valve spindle link pin is 80 mm.
07
OR
Q.4 (a) Explain the design procedure of sunk key 07
(b) What is coupler? Explain step by step design procedure for coupler 07
Q.5 (a) Derive an equation for torque required to lower the load of square threaded power
screw
07
(b) Design a rigid type cast iron flange coupling for a steel shaft transmitting 15 KW
at 200 rpm and having an allowable shear stress of 40 KN/mm?. The maximum
07
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Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?III (Old) EXAMINATION ? WINTER 2019
Subject Code: 131902 Date: 28/11/2019
Subject Name: Machine Design & Industrial Drafting
Time: 02:30 PM TO 05:30 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain hole-based and shaft based limit system with neat sketch. 07
(b) Define (1) Crushing stress (2) Preferred Number (3) Factor of Safety
(4) Residual stress (5) transverse stress (6) Static Load (7) Shock load
07
Q.2 (a) Explain different failures of riveted joint with neat sketches. 07
(b) A double riveted lap joint is made between 18 mm thick plates. The rivet diameter
and pitch are 24 mm and 72 mm respectively. If the ultimate stresses are 415
MPa in tension, 330 MPa in shear and 675 MPa in crushing, find the minimum
force per pitch which will rupture the joint. If the above joint is subjected to a
load such that the factor of safety is 4, find out the actual stresses developed in
the plates and the rivets.
07
OR
(b) A double riveted single cover butt joint in plates 22 mm thick is made with 25
mm diameter rivets at 85 mm pitch. The permissible stresses are: ?t = 100 MPa;
? = 85 MPa; ?c = 120 MPa. Find the efficiency of joint.
07
Q.3 (a) Design a socket and spigot cotter joint to support a load varying from 35 kN in
compression to 35 kN in tension. The material used is carbon steel for which the
allowable are: ?t = ?c = 55 MPa; ? = 40 MPa and crushing stress = 100 MPa. The
load is applied statically.
07
(b) Design a knuckle joint to connect two steel rods under a tensile load of 35KN.
The allowable stresses are 60MPa in tension 55MPa, in shear and 85MPa in
crushing
07
OR
Q.3 (a) Find the diameter of a solid shaft to transmit 30 kW at 230 rpm. The shear stress
is 50 MPa. If a hollow shaft is to be used in place of solid shaft, find the inside
and outside diameter when the ratio of inside to outside diameter is 6:8
07
(b) Write practical applications of shaft and axle. 07
Q.4 (a) Explain with sketch design procedure of bell crank lever 07
(b) A lever safety valve is 75 mm in diameter. It is required to blow off at 1.3 N/mm2.
Design the mild steel lever of rectangular cross-section if the permissible stresses
are 70 MPa in tension, 52.5 MPa in shear and 24.5 MPa in bearing. The pin is
made of the same material as that of the lever. The distance from the fulcrum to
the dead weight of the lever is 800 mm and the distance between the fulcrum pin
and the valve spindle link pin is 80 mm.
07
OR
Q.4 (a) Explain the design procedure of sunk key 07
(b) What is coupler? Explain step by step design procedure for coupler 07
Q.5 (a) Derive an equation for torque required to lower the load of square threaded power
screw
07
(b) Design a rigid type cast iron flange coupling for a steel shaft transmitting 15 KW
at 200 rpm and having an allowable shear stress of 40 KN/mm?. The maximum
07
2
torque is 25% greater than full load torque. The working stress in bolt should not
exceed 30 KN/mm?. Assume that same material is used for shaft and key and that
crushing stress is twice value of its shear stress. The shear stress for cast iron is
14 KN/mm?.
OR
Q.5 (a) A power screw having double start square threads of 25 mm nominal diameter
and 5 mm pitch is acted upon by an axial load of 10 KN. The outer and inner
diameters of screw collar are 50 mm and 20 mm respectively. The coefficient of
thread friction and collar friction may be assumed as 0.2 and 0.15 respectively.
The screw rotates at 12 R.P.M. Assuming uniform wear condition at the collar
and allowable thread bearing pressure of 5.8 N/mm
2
, Find: 1. the torque required
to rotate the screw; 2. the stress in the screw; and 3. the number of threads of nut
in engagement with screw.
07
(b) Explain any four editing commands of AUTOCAD 07
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This post was last modified on 20 February 2020