287 / 392
Table 2. Strains and stresses
Computation results
Welded diaphragmas Unwelded
4 supports
2.389
2.42
Deformation
[
mm
]
3 supports
2.46
2.49
4 supports
5.73
5.76
Stress
[
kN/cm
2
]
3 supports
6.27
7.43
Table 3. Reduced model
3 DOF
6 DOF
membrane
Deformation
[
mm
]
2.389
2.501
2.696
Stress
[
kN/cm
2
]
5.73
6.74
6.25
3.4. Failure analysis and reconstruction of the excavator platform ARS Kopel
During service of slewing spreader platform ARS 1400/22+60+21 O&K, warping of
some plates of the rotary platform (Fig. 8) occurred, requiring platform reconstruction.
Figure 8. The half–model of the platform and deformation field
The largest stress value (Table 4 and Fig. 9), the largest deformation energy, and stress
concentration were situated in the vertical plates. This was also experienced in service.
Increase of vertical plate thickness eliminated stress concentration and decreased the
stress. Static behaviour was confirmed by computation of free oscillations (Fig. 10).
Table 4. Percentual portions of stresses and deformation energy
Element
Load Membrane/Bend Deformation energy
1
18.8/5.8
15.2
Upper plate
2
16.2/6.6
11.7
1
15.8/4.3
15.0
Lower plate
2
15.0/4.9
12.5
1
45.0/5.4
69.2 (39.7)
Vertical plates
2
46.6/5.3
75.1 (41.8)
1
3.1/0.6
0.5
Ribs of the upper plate
2
3.6/0.7
0.6
1
0.7/0.6
0.1
Ribs of the lower plate
2
0.6/0.6
0.1
1
83.6/16.7
100
Sum
2
82.0/18.0
100
283