Re-Test Paper
Date: 10-Sep-2007
N. B.: Answer Q.1 or Q.2, Q.3 or Q.4, Q.5 or Q.6
Each question carries 10 marks. (Marks are equally divided for sub-questions)
Q.1 An air compressor receiver consists of cylindrical portion of A mm length and B mm diameter. It has hemispherical ends. If the inner pressure is not to exceed C N/mm² and permissible tensile stress is D N/mm², calculate wall thickness at shell and at end assuming it to be a thin vessel and assuming the joint efficiencies of 0.8 and 0.9 for shell and end respectively. Also determine storage capacity of the vessel.
|
Variable |
Group 1 (Divisible by 3) |
Group 2 (Even) |
Group 3 (Odd) |
|
A |
1700 |
2100 |
2300 |
|
B |
900 |
850 |
1100 |
|
C |
3 |
2.5 |
4 |
|
D |
65 |
75 |
70 |
Q.2 A closed vessel is to be designed to withstand internal pressure of A MPa and is to have B mm internal diameter. Assuming Syt = C MPa, Sut = D MPa, Poisson’s ratio = E FS = F determine wall thickness on the basis of Max. principal stress theory, Max. shear stress theory, Max. principal strain theory and Distortion energy theory.
|
Variable |
Group 1 (Divisible by 3) |
Group 2 (Even) |
Group 3 (Odd) |
|
A |
50 |
54 |
58 |
|
B |
450 |
430 |
440 |
|
C |
350 |
300 |
250 |
|
D |
650 |
500 |
450 |
|
E |
0.27 |
0.31 |
0.33 |
|
F |
1.6 |
1.8 |
1.4 |
Q.3 a) Write all valid structure formulae for z-speed gear box.
|
Variable |
Group 1 (Even) |
Group 2 (Odd) |
|
Z |
4 |
6 |
b) Draw structure diagram for any one valid structure formula for a z-speed gear box.
|
Variable |
Group 1 (Even) |
Group 2 (Odd) |
|
Z |
18 |
12 |
Q.4 a) Draw ray diagram for z = 3(2) 2(6) 3(1) so that all shafts would have minimum possible diameters assuming Nmin = A rpm, Ø = B, Nmotor = C rpm.
|
Variable |
Group 1 (Even) |
Group 2 (Odd) |
|
A |
20 |
15 |
|
B |
1.3 |
1.32 |
|
C |
1500 |
1440 |
b) Draw speed diagram for z = 2(1) 2(2) 2(4) so that all shafts would have minimum possible diameters assuming Nmin = A rpm, Ø = B, Nmotor = C rpm.
|
Variable |
Group 1 (Even) |
Group 2 (Odd) |
|
A |
80 |
35 |
|
B |
1.5 |
1.45 |
|
C |
1200 |
500 |
Q.5 A thin walled spherical pressure vessel is to be designed so that weight of empty vessel should not exceed A kg. Select material to design the vessel for the objective of maximizing gas storage capacity and internal pressure of B N/mm² with FS = C out of following materials
|
Material |
ρ (kg/m³) |
Sut (N/mm²) |
|
M1 |
D |
G |
|
M2 |
E |
H |
|
M3 |
F |
I |
|
Variable |
Group 1 (1 to 31) |
Group 2 (32 to 62) |
|
A |
130 |
150 |
|
B |
4 |
5 |
|
C |
3 |
2.5 |
|
D |
7800 |
8000 |
|
E |
3000 |
2800 |
|
F |
8200 |
8400 |
|
G |
500 |
520 |
|
H |
270 |
250 |
|
I |
450 |
410 |
Q.6 A shaft is to be designed to transmit A kW of power at B rpm. Select suitable material for shaft from following list so that the shaft will have minimum weight and torsional rigidity of C Nm/degree, assuming FS = D.
|
Material |
ρ (kg/m³) |
Syt (N/mm²) |
G (N/mm²) |
|
M1 |
E |
H |
K |
|
M2 |
F |
I |
L |
|
M3 |
G |
J |
M |
|
Variable |
Group 1 (1 to 31) |
Group 2 (32 to 62) |
|
A |
12 |
10 |
|
B |
1200 |
1440 |
|
C |
90 |
100 |
|
D |
3 |
3.5 |
|
E |
7800 |
7700 |
|
F |
5000 |
5400 |
|
G |
2500 |
2300 |
|
H |
550 |
540 |
|
I |
400 |
410 |
|
J |
350 |
340 |
|
K |
90 |
85 |
|
L |
70 |
72 |
|
M |
82 |
80 |
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