Page 135 - Fundamental Of Design In Mechanical Engineering

Example 2

A plate of 100mm x 10mm thick is under force of 120kN. Calculate the

length of the plate needed if the welded connection is using a class 400

MPa electrode.

For class 400MPa electrode, allowable shear stress 120MPa. Since the
plate is more than 6.4 mm, the maximum filet weld size is 1.6mm less than

the thickness of the plate.

P = Sv x 0.707 x size x length

120x 10 =120x10 x0.707 x (0.01-0.0016)x2L
6
3
L = 0.0842m =84.2mm.

Example 3

Determine the safe load for the butt weld that connects two plates of 100mm

thick and 200mm long if the allowable shear stress is 140MPa.

P = (S)(t)(l)

6
= 140 x 10 x 0.2 x 0.1
= 2.8 MN. 135