Shear Stress:

Shear Stress:

The stresses acting perpendicular to the surfaces considered are normal stresses and

were discussed in the preceding section.

Now consider a bolted connection in which two plates are connected by a bolt with cross

section A 

The tensile loads applied on the plates will tend to shear the bolt at the section AA.

Hence, it can be easily concluded from the free body diagram of the bolt that the internal

resistance force V must act in the plane of the section AA and it should be equal to the

external load P.

These internal forces are called shear forces and when they are divided by the

corresponding section area, we obtain the shear stress on that section

   

                                          

τ = V/A

 The average value of the shear stress on the cross section and the

distribution of them over the area is not uniform.

In general, the shear stress is found to be maximum at the centre and zero at certain

locations on the edge. This will be dealt in detail in shear stresses in beams  the bolt experiences shear stresses on a single plane in its body and hence it

is said to be under single shear

the bolt experiences shear on two sections AA and BB. Hence, the bolt is

said to be under double shear and the shear stress on each section is

V P

A 2A

τ = V/A = P/2A

Assuming that the same bolt is used in the assembly as shown in figure 1.5 and 1.6 and

the same load P is applied on the plates, we can conclude that the shear stress is reduced

by half in double shear when compared to a single shear.

Shear stresses are generally found in bolts, pins and rivets that are used to connect

various structural members and machine components.