Screw & Riveted Joints
Dr. Md. Zahurul Haq, Ph.D., CEA, FBSME, FIEB
Professor
Department of Mechanical Engineering
Bangladesh University of Engineering & Technology (BUET)
Dhaka-1000, Bangladesh
http://zahurul.buet.ac.bd/
ME 201: Elements of Theory of Machines and Machine Design
(for Textile Engineering)
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Riveted Joints
Types of Riveted Joints
1
Lap joint: A lap joint is that in which one plate overlaps the other
and the two plates are then riveted together.
2
Butt Joint: A butt joint is that in which the main plates are kept in
alignment butting each other and a cover plate is placed either on one
side or on both sides of the main plates. The cover plate is then
riveted together with the main plates.
A018
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Riveted Joints
Examples of Lap Joints
A010
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Riveted Joints
Examples of Butt Joints
A011
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Important Terms Used in Riveted Joints
Pitch, p: It is the distance from the centre of one rivet to the centre
of the next rivet measured parallel to the seam.
Back pitch, pb : It is the perpendicular distance between the centre
lines of the successive rows.
Diagonal pitch, pd : It is the distance between the centres of the
rivets in adjacent rows of zig-zag riveted joint.
Marginal pitch, m: It is the distance between the centre of rivet hole
to the nearest edge of the plate.
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Riveted Joints
Failures of a Riveted Joint
1. Tearing of the plate at an edge:
A012
This can be avoided by keeping the margin, m = 1.5d, where d is the diameter of
the rivet hole.
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2. Tearing of the plate across a row of rivets:
A013
Pt = At σt = (p − d)tσt
where, Pt is the tearing resistance, σt is the permissible tensile stress for
the plate material, t is the plate thickness.
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3. Shearing of the rivets:
A015
A014
(c) Shearing off a rivet in double cover butt joint.
Ps = n s A s τ s = n s
π 2
4d
τs
where, Ps is the shearing resistance of rivets, ns is the total number of
shearing surfaces, and τs is the permissible shearing stress.
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Riveted Joints
A020
A021
Bolt subject to single shear.
A022
A023
Bolts subject to double shear.
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4. Crushing of the plate or rivets:
A019
A016
Pc = nc Ac σc = nc (dt)σc
where, Pc is the crushing resistance, nc is the number of rivets per pitch
length under crushing, and σc is the permissible crushing stress for the
rivet or plate material.
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Efficiency of a Riveted Joint
Pjoint = min(Pt , Ps , Pc )
Pplate = ptσt
ηjoint =
© Dr. Md. Zahurul Haq (BUET)
Pjoint
Pplate
× 100
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Find the efficiency of the following riveted joints:
1
Single riveted lap joint of 6 mm plates with 20 mm diameter rivets having a
pitch of 50 mm.
2
Double riveted lap joint of 6 mm plates with 20 mm diameter rivets having a
pitch of 65 mm. (Ans. η = 69.2%)
Assume,
Permissible tensile stress in plate = 120 MPa
Permissible shearing stress in rivets = 90 MPa
Permissible crushing stress in rivets = 180 MPa
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Riveted Joints
A017
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