2. Two plates 16 mm thick are joined by a double riveted lap joint. The pitch of each row of rivets is 90 mm. The rivets are 25 mm in diameter. The permissible stresses are as follows : o, = 140 MPa ; t = 110 MPa and o = 240 MPa Find the efficiency of the joint. [Ans. 53.5%]
2. Two plates 16 mm thick are joined by a double riveted lap joint. The pitch of each row of rivets is 90 mm. The rivets are 25 mm in diameter. The permissible stresses are as follows : o, = 140 MPa ; t = 110 MPa and o = 240 MPa Find the efficiency of the joint. [Ans. 53.5%]
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
Related questions
Question
100%
exercise number 2,3,4,5,8,12
![Riveted Joints
- 337
1
-× + (240)³
12
(23.5) + 2xt × 23.5 (30² + 90²)
= 1152 x 103 t – [4326 t + 423 × 10³ t] = 724 674 t mm4
Bending moment,
M = P x e = 100 × 10³ × 75
60
= 7500 x 10° N-mm
240
Distance of neutral axis (X–X) from the top most fibre
of the plate,
X
30-x
30
240
= 120 mm
2
+ 60
y =
2
%3D
M
Ld = 23,5
We know that
%3D
y
All dimensions in mm.
7500 x 10
125
Fig. 9.36
or
724 674 t
120
10.35
=9.95 say 10 mm
1.04
10.35
..
=1.04 or t =
Ans.
EXERCISES
1. A single riveted lap joint is made in 15 mm thick plates with 20 mm diameter rivets. Determine the
strength of the joint, if the pitch of rivets is 60 mm. Take 0, = 120 MPa; t = 90 MPa and o = 160 MPa.
[Ans. 28 280 NI
2. Two plates 16 mm thick are joined by a double riveted lap joint. The pitch of each row of rivets is 90
mm. The rivets are 25 mm in diameter. The permissible stresses are as follows :
0, = 140 MPa ; t = 110 MPa and o. = 240 MPa
Find the efficiency of the joint.
[Ans. 53.5%]
3. A single riveted double cover butt joint is made in 10 mm thick plates with 20 mm diameter rivets
with a pitch of 60 mm. Calculate the efficiency of the joint, if
0, = 100 MPa ;T = 80 MPa and o = 160 MPa.
[Ans. 53.8%]
4. A double riveted double cover butt joint is made in 12 mm thick plates with 18 mm diameter rivets.
Find the efficiency of the joint for a pitch of 80 mm, if
0, = 115 MPa ; t = 80 MPa and o = 160 MPa.
[Ans. 62.6%]
5. A double riveted lap joint with chain riveting is to be made for joining two plates 10 mm thick. The
allowable stresses are : 0, = 60 MPa ; t = 50 MPa and o = 80 MPa. Find the rivet diameter nitoh of
rivets and distance between rows of rivets. Also find the efficiency of the joint.
351 / 1251
[Ans. d = 20 mm ; p = 73 mm; p, = 38 mı
6. A triple riveted lap joint with zig-zag riveting is to be designed to connect two plates G
ness. Determine the dia. of rivet, pitch of rivets and distance between the rows of rivet. In..
the joint will fail. Assume : 0, = 120 MPa ; t = 100 MPa and o = 150 MPa.
[Ans. d = 14 mm ; p = 78 mm; p, = 35.2 mm]
7. A double riveted butt joint, in which the pitch of the rivets in the outer rows is twice that in the inner
rows, connects two 16 mm thick plates with two cover plates each 12 mm thick. The diameter of rivets
is 22 mm. Determine the pitches of the rivets in the two rows if the working stresses are not to exceed
the following limits:
Тор
Contents
338 · A Textbook of Machine Design
Tensile stress in plates = 100 MPa ; Shear stress in rivets = 75 MPa; and bearing stress in rivets and
plates = 150 MPa.
Make a fully dimensioned sketch of the joint by showing at least two views.
[Ans. 107 mm, 53.5 mm]
8. Design a double riveted double strap butt joint for the longitudinal seam of a boiler shell, 750 mm in
diameter, to carry a maximum steam pressure of 1.05 N/mm² gauge. The allowable stresses are :s
0, = 35 MPa; t = 28 MPa and o = 52.5 MPa
Assume the efficiency of the joint as 75%.
[Ans. t = 16 mm ; d = 25 mm ; p = 63 mm ; p, = 37.5 mm ; t, =t, = 10 mm ; m = 37.5 mm]
9. Design a triple riveted double strap butt joint with chain riveting for a boiler of 1.5 m diameter and
carrying a pressure of 1.2 N/mm2. The allowable stresses are :
o, = 105 MPa ; t = 77 MPa and 0, = 162.5 MPa
[Ans. d = 20 mm; p = 50 mm]
10. Design a triple riveted longitudinal double strap butt joint with unequal straps for a boiler. The inside
diameter of the longest course of the drum is 1.3 metres. The joint is to be designed for a steam
pressure of 2.4 N/mm?. The working stresses to be used are :
0, = 77 MPa; t = 62 MPa and o, = 120 MPa
Assume the efficiency of the joint as 81%.
[Ans. t = 26 mm; d = 31.5 mm ; p = 200 mm ; t, = 19.5 mm ; t,= 16.5 mm ; m = 47.5 mm]
11. Design the longitudinal and circumferential joint for a boiler whose diameter is 2.4 metres and is
subjected to a pressure of 1 N/mm². The longitudinal joint is a triple riveted butt joint with an effi-
ciency of about 85% and the circumferential joint is a double riveted lap joint with an efficiency of
about 70%. The pitch in the outer rows of the rivets is to be double than in the inner rows and the
width of the cover plates is unequal. The allowable stresses are :
0, = 77 MPa ; t = 56 MPa and o = 120 MPa
Assume that the resistance of rivets in double shear is 1.875 times that of single shear. Draw the
complete joint.
12. A triple riveted butt joint with equal double cover plates (zig-zag riveting) is used for the longitudinal
joint of a Lancashire boiler of 2.5 m internal diameter. The working steam pressure is 1.12 N/mm² and
the efficiency of the joint is 85 per cent. Calculate the plate thickness for mild steel of 460 MPa
ultimate tensile strength. Assume ratio of tensile to shear stresses as 7/6 and factor of safety 4. The
resistance of the rivets in double shear is to be taken as 1.875 times that of single shear. Design a
suitable circumferential joint also.
13. Two lengths of mild steel flat tie bars 200 mm × 10 mm are to be connected by a double riveted double
cover butt joint, using 24 mm diameter rivets. Design the joint, if the allowable working stresses are 112
MPa in tension, 84 MPa in shear and 200 MPa in crushing.
[Ans. n = 5; 1 = 88%]
14. Two mild steel tie bars for a bridge structure are to be joined by a double cover butt joint. The
thickness of the tie bar is 20 mm and carries a tensile load of 400 kN. Design the joint if the allowable
stresses are : o, = 90 MPa ; t= 75 MPa and o = 150 MPa.
Assume the strength of rivet in double shear to be 1.75 times that of in single shear.
[Ans, b = 150 mm ; d = 27 mm ; n = 6 ; ŋ = 90%]
15. Two lengths of mild steel tie rod having width 200 mm are to be connected by means of Lozenge joint
with two cover plates to withstand a tensile load of 180 kN. Completely design the joint, if the permis-
sible stresses are 80 MPa in tension; 65 MPa in shear and 160 MPa in crushing. Draw a neat sketch of
the joint.
[Ans. t = 13 mm ; d = 22 mm ; n = 5 ; ŋ = 86.5%]
16. A bracket is supported by means of 4 rivets of same size, as shown in Fig. 9.37. Determine the
diameter of the rivet if the maximum shear stress is 140 MPa.
[Ans. 16 mm]](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Faf983c25-dc6b-47a8-a5c0-1893134f210d%2Fb0ac2a60-af0a-4e16-8ab4-f23d90ca21e6%2Fucpnz3z_processed.jpeg&w=3840&q=75)
Transcribed Image Text:Riveted Joints
- 337
1
-× + (240)³
12
(23.5) + 2xt × 23.5 (30² + 90²)
= 1152 x 103 t – [4326 t + 423 × 10³ t] = 724 674 t mm4
Bending moment,
M = P x e = 100 × 10³ × 75
60
= 7500 x 10° N-mm
240
Distance of neutral axis (X–X) from the top most fibre
of the plate,
X
30-x
30
240
= 120 mm
2
+ 60
y =
2
%3D
M
Ld = 23,5
We know that
%3D
y
All dimensions in mm.
7500 x 10
125
Fig. 9.36
or
724 674 t
120
10.35
=9.95 say 10 mm
1.04
10.35
..
=1.04 or t =
Ans.
EXERCISES
1. A single riveted lap joint is made in 15 mm thick plates with 20 mm diameter rivets. Determine the
strength of the joint, if the pitch of rivets is 60 mm. Take 0, = 120 MPa; t = 90 MPa and o = 160 MPa.
[Ans. 28 280 NI
2. Two plates 16 mm thick are joined by a double riveted lap joint. The pitch of each row of rivets is 90
mm. The rivets are 25 mm in diameter. The permissible stresses are as follows :
0, = 140 MPa ; t = 110 MPa and o. = 240 MPa
Find the efficiency of the joint.
[Ans. 53.5%]
3. A single riveted double cover butt joint is made in 10 mm thick plates with 20 mm diameter rivets
with a pitch of 60 mm. Calculate the efficiency of the joint, if
0, = 100 MPa ;T = 80 MPa and o = 160 MPa.
[Ans. 53.8%]
4. A double riveted double cover butt joint is made in 12 mm thick plates with 18 mm diameter rivets.
Find the efficiency of the joint for a pitch of 80 mm, if
0, = 115 MPa ; t = 80 MPa and o = 160 MPa.
[Ans. 62.6%]
5. A double riveted lap joint with chain riveting is to be made for joining two plates 10 mm thick. The
allowable stresses are : 0, = 60 MPa ; t = 50 MPa and o = 80 MPa. Find the rivet diameter nitoh of
rivets and distance between rows of rivets. Also find the efficiency of the joint.
351 / 1251
[Ans. d = 20 mm ; p = 73 mm; p, = 38 mı
6. A triple riveted lap joint with zig-zag riveting is to be designed to connect two plates G
ness. Determine the dia. of rivet, pitch of rivets and distance between the rows of rivet. In..
the joint will fail. Assume : 0, = 120 MPa ; t = 100 MPa and o = 150 MPa.
[Ans. d = 14 mm ; p = 78 mm; p, = 35.2 mm]
7. A double riveted butt joint, in which the pitch of the rivets in the outer rows is twice that in the inner
rows, connects two 16 mm thick plates with two cover plates each 12 mm thick. The diameter of rivets
is 22 mm. Determine the pitches of the rivets in the two rows if the working stresses are not to exceed
the following limits:
Тор
Contents
338 · A Textbook of Machine Design
Tensile stress in plates = 100 MPa ; Shear stress in rivets = 75 MPa; and bearing stress in rivets and
plates = 150 MPa.
Make a fully dimensioned sketch of the joint by showing at least two views.
[Ans. 107 mm, 53.5 mm]
8. Design a double riveted double strap butt joint for the longitudinal seam of a boiler shell, 750 mm in
diameter, to carry a maximum steam pressure of 1.05 N/mm² gauge. The allowable stresses are :s
0, = 35 MPa; t = 28 MPa and o = 52.5 MPa
Assume the efficiency of the joint as 75%.
[Ans. t = 16 mm ; d = 25 mm ; p = 63 mm ; p, = 37.5 mm ; t, =t, = 10 mm ; m = 37.5 mm]
9. Design a triple riveted double strap butt joint with chain riveting for a boiler of 1.5 m diameter and
carrying a pressure of 1.2 N/mm2. The allowable stresses are :
o, = 105 MPa ; t = 77 MPa and 0, = 162.5 MPa
[Ans. d = 20 mm; p = 50 mm]
10. Design a triple riveted longitudinal double strap butt joint with unequal straps for a boiler. The inside
diameter of the longest course of the drum is 1.3 metres. The joint is to be designed for a steam
pressure of 2.4 N/mm?. The working stresses to be used are :
0, = 77 MPa; t = 62 MPa and o, = 120 MPa
Assume the efficiency of the joint as 81%.
[Ans. t = 26 mm; d = 31.5 mm ; p = 200 mm ; t, = 19.5 mm ; t,= 16.5 mm ; m = 47.5 mm]
11. Design the longitudinal and circumferential joint for a boiler whose diameter is 2.4 metres and is
subjected to a pressure of 1 N/mm². The longitudinal joint is a triple riveted butt joint with an effi-
ciency of about 85% and the circumferential joint is a double riveted lap joint with an efficiency of
about 70%. The pitch in the outer rows of the rivets is to be double than in the inner rows and the
width of the cover plates is unequal. The allowable stresses are :
0, = 77 MPa ; t = 56 MPa and o = 120 MPa
Assume that the resistance of rivets in double shear is 1.875 times that of single shear. Draw the
complete joint.
12. A triple riveted butt joint with equal double cover plates (zig-zag riveting) is used for the longitudinal
joint of a Lancashire boiler of 2.5 m internal diameter. The working steam pressure is 1.12 N/mm² and
the efficiency of the joint is 85 per cent. Calculate the plate thickness for mild steel of 460 MPa
ultimate tensile strength. Assume ratio of tensile to shear stresses as 7/6 and factor of safety 4. The
resistance of the rivets in double shear is to be taken as 1.875 times that of single shear. Design a
suitable circumferential joint also.
13. Two lengths of mild steel flat tie bars 200 mm × 10 mm are to be connected by a double riveted double
cover butt joint, using 24 mm diameter rivets. Design the joint, if the allowable working stresses are 112
MPa in tension, 84 MPa in shear and 200 MPa in crushing.
[Ans. n = 5; 1 = 88%]
14. Two mild steel tie bars for a bridge structure are to be joined by a double cover butt joint. The
thickness of the tie bar is 20 mm and carries a tensile load of 400 kN. Design the joint if the allowable
stresses are : o, = 90 MPa ; t= 75 MPa and o = 150 MPa.
Assume the strength of rivet in double shear to be 1.75 times that of in single shear.
[Ans, b = 150 mm ; d = 27 mm ; n = 6 ; ŋ = 90%]
15. Two lengths of mild steel tie rod having width 200 mm are to be connected by means of Lozenge joint
with two cover plates to withstand a tensile load of 180 kN. Completely design the joint, if the permis-
sible stresses are 80 MPa in tension; 65 MPa in shear and 160 MPa in crushing. Draw a neat sketch of
the joint.
[Ans. t = 13 mm ; d = 22 mm ; n = 5 ; ŋ = 86.5%]
16. A bracket is supported by means of 4 rivets of same size, as shown in Fig. 9.37. Determine the
diameter of the rivet if the maximum shear stress is 140 MPa.
[Ans. 16 mm]
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