met 304 revited joints

Riveted Joints

Riveting applications RivetsTypes of riveted joints Failure of riveted joints

Riveting applications:

Pressure vessels, boilerstanksBridgesHulls of shipsAirplanesCranesbuildingsMachinery in general

RivetsA rivet is a round bar consisting

of head shank.The rivet blank is heated to a

red glow Inserted into the holes;The head is held firmly against

the plateThe projecting end is formed

into a second head, called the point,

head

PointShank

Rivet material:

•Tough and ductile low carbon steel

•Nickel steel. •Brass•Aluminium

Types of riveted joints:

Lap joints

butt joints

Strap Rivet

Riveted joint terminology.

(pPitch )

Gauge line

tBack pitch (p )

( )

Margin lapdistance m

Failure of riveted joints

Bending of rivet or plate FF

•In Lap connections the offset creates a moment• M=Ft/2•Bending moment causes complex deformations and stresses •In most cases this offset moment is neglected •A suitable factor of safety is used.

b) Shearing of the rivets:

Single shear

Double shear

FF/2

F/2

F

F

F

Joint strength in shear

Where, n1: :number of rivets in single shear n2: number of rivets in double shear Ss: allowable shear stress d : diameter of rivet

4Sπd)nn(2F s

212s

c) Crushing of the rivets or the plates

Crushing of margin

F F

Crushing of the rivet or plate occurs due to the pressure on the cylindrical surface of the rivet and the plate The resistance to crushing of rivets is,

c2112c dS)hnh(nF whereh1 و h2: plate thicknessSc: allowable crushing stress

d) Rupture of plate by tension:

Rupture of plate occurs at the section between the rivets

The resistance of rupture can be obtained from the expression:

Where: L: plate width h: plate thickness: St : allowable tensile stress n : number of rivet holes at the section

tt hS)ndL(F

FF

L

In the undrilled section:

Where L : width of plate

tt LhSF

FF

Undrilled Section

L

d) Tearing and shearing of the margin

For the riveted joint to resist tearing and shearing of the margin, the margin (m) =

1.5 d for double shear2d for single shear.

Shearing of the margin

Tearing of the margin

F F

F F

Margin

Example:Fig.(3) shows a lap riveted joint, consists of two Rolled steel plates, SAE 1020, of 0.5 in thickness. The plates are riveted together with four rivets 0.375 inch in diameter of low carbon steel, SAE 1010. Estimate the maximum value of the force F that the joint can stand while considering a factor of safety equals 2 and the rivets are driven by hand hammer.

FF

0.5 in

4 in. 2

1 1

Solution

s

s2

12s f4Sdπ)nn(2F

2410000.3750π4F

2

s

Shearing of the rivets:d = 0.375fs = 2n1 = 4n2 =0

FS = 2209 lb

Load carrying member Type of stress Rivet-driving power

Rivets acting in single shear

Rivets acting in double shear

Rolled steel, SAE 1020 Tension ….. 18000 18000

Rivets, SAE1010

Shear Power 13500 13500Shear Hand 10000 10000

Crushing Power 24000 30000Crushing Hand 16000 20000

Crushing of the rivets:

s

c2112c f

dS)hnh(nF

2160005.0375.04Fc

FC = 6000 lb





Rivets, SAE1010



Rupture of plate by tension

s

tt f

hS)ndL(F

2180005.0)375.024(Ft

Ft = 14625 lb





Rivets, SAE1010



Crushing of the plates

s

c2112c f

dS)hnh(nF

236000375.05.04Fc

FC = 13500 lb

Maximum value of F = 2209 lb





Rivets, SAE1010



Design procedure for structural joints

161h2d

The following sequence of steps applies to the calculations for structural joints:• The load on each member is determined analytically or graphically

• The shape and size of each member is determined based on the load

• The diameter of the rivets is determined by the thickness of the structural shapes apply the equation:

• The margin of the edge parallel to the load

d3ph16

d5.11m

d22m • The margin of the edge normal to the load

•Pitch limit:

where h is the thickness of the thinnest plate used in the joint

•The number of rivets required is based upon the shearing or crushing stress which ever determine the cause of failure.

•The rivets in the joint are spaced in order to utilize the material economically

•avoiding eccentric loading as far as possible

Thank You

met 304 revited joints

Education