Page 256 - Handbook of Materials Failure Analysis

252 CHAPTER 10 A reliable analysis method

4 RESULTS AND DISCUSSION
A heavy shovel is employed to simulate and validate the model against static and test
data. The fatigue lives of front-end hot spots are then estimated. The structural
dynamics of the shovel is simulated using the hoist rope force and swing motion
as inputs. The dynamic stresses of front-end structural hot spots are recovered and
compared with the static and test results reported by Zhang [21], where (i) the static
stresses of boom and handle were calculated for the shovel; and (ii) the dynamic
stresses of boom and handle were investigated by analyzing field test data on the
shovel. The details are presented below.

4.1 SIMULATION AND VALIDATION OF FRONT-END MODEL
Figure 10.10a and b indicates the dynamic loading on the front-end model in the local
coordinate system o (x,y,z) during the one working cycle of 60 s. They consist of
Figure 10.10a with the load at the hoist rope; and Figure 10.10b, the swing angular
displacement at the revolving center o in the y direction.
450
400
Hoist rope tension (KN) 300
350

250
200
150
100
50
0
0 10 20 30 40 50 60
(a) Time (s)
90
80
70
60
Angle (°) 50
40
30
20
10
0
0 10 20 30 40 50 60
(b) Time (s)
FIGURE 10.10
Dynamic loads on the shovel front-end with time: (a) load at hoist rope and (b) swing angular
displacement at the revolving center.