219 / 352
215
Figure 6.1: Palette-pack machine
Figure 6.2:In-service crack and failure
The drive-unit consists of an electromotor, angular velocity 730 rot/min, gear box,
catenary and chain linked to the structure of palette. During operation, the failure was
observed in diagonals of palette, on the frame and in the nexus which was moving the
palette (Fig. 6.1, Fig. 6.2). It repeated about every 30 days of service, with fractured
nexus, palette or the frame. The problem had to be analysed by both numerical and
experimental approach.
As the electromotor frequency is 12.2Hz, behaviour of the frame is satisfactory in both
cases.
6.1. Finite element analysis
The view of frame and the palette, with corresponding FE models, are presented in
Figs. 6.3 to 6.9.
f
01
=26.7 Hz
f
01
=33.7 Hz
Figure 6.3: Frame
Figure 6.4: Dynamic behaviour of the frame