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Welding, Bonding, and the Design of Permanent Joints 485

EXAMPLE 9–1 A 50-kN load is transferred from a welded fitting into a 200-mm steel channel as illus-
trated in Fig. 9–14. Estimate the maximum stress in the weld.
Solution 3 (a) Label the ends and corners of each weld by letter. See Fig. 9–15. Sometimes it is
desirable to label each weld of a set by number.

(b) Estimate the primary shear stress τ . As shown in Fig. 9–14, each plate is welded to
the channel by means of three 6-mm fillet welds. Figure 9–15 shows that we have
divided the load in half and are considering only a single plate. From case 4 of
Table 9–1 we find the throat area as
A = 0.707(6)[2(56) + 190] = 1280 mm 2
Then the primary shear stress is
V 25(10) 3

τ = = = 19.5MPa
A 1280
(c) Draw the τ stress, to scale, at each lettered corner or end. See Fig. 9–16.

(d) Locate the centroid of the weld pattern. Using case 4 of Table 9–1, we find
(56) 2
¯ x = = 10.4mm
2(56) + 190
This is shown as point O on Figs. 9–15 and 9–16.
(e) Find the distances r i (see Fig. 9–16):
2
2 1/2
r A = r B = [(190/2) + (56 − 10.4) ] = 105 mm
2 1/2
2
r C = r D = [(190/2) + (10.4) ] = 95.6mm
These distances can also be scaled from the drawing.
Figure 9–14
6 200 6
Dimensions in millimeters.
50 kN
6 6 100

56
200
190
6
Figure 9–15
Diagram showing the weld 25 kN
geometry on a single plate; all
dimensions in millimeters. 100
110.4
Note that V and M represent the
reaction loads applied by the C D
welds to the plate.
V O y
56
45.6
M
B A
95
x

3 We are indebted to Professor George Piotrowski of the University of Florida for the detailed steps,
presented here, of his method of weld analysis R.G.B, J.K.N.