WCA September 2016

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Wire & Cable ASIA – September/October 2016
Introduction
The design of a stranding and closing planetary machine
with back-twist is not a simple project, due to the
“planetary” rotation of the parts: that introduces dynamic
effects that are difficult to estimate; in particular if the
performance is extreme due to large spool mass, load
configurations and rotation speed.
In order to avoid any possible risk and to obtain the most
precise design input, MFL involves EnginSoft and its
simulation capabilities as reliable partner in this project.
For this specific project, EnginSoft is in charge of carrying
out the whole dynamical assessment of the planetary
machine. In order to achieve reliable and precise results,
it is necessary to use a powerful and versatile multi-body
software: RecurDyn®. On the other hand, MFL has to
complete the design of all parts in order to meet structural
requirement in terms of strength and lifetime.
Methods and problem definition
This colossal planetary machine will be used to produce
cable with different diameters and strand combinations, so
that the spools loaded on the machine can be different in
size and position on the main rotor. In addition, the spools
are naturally unbalanced due to winding errors.
This results in various load scenarios to be analysed.
The goal is the identification of the worst case in terms
of power required to the motors and stress on parts.
EnginSoft’s engineers are in charge of finding out such
worst conditions through dynamic simulation.
The approach starts with a single cage, and an analysis
defines the worst configuration. After that, together with
MFL, finite load scenarios are defined.
The next step is the dynamic simulation of the different
load scenarios by applying the worst cage condition
previously defined. At the end it is possible to obtain the
worst working condition of the whole machine.
Design Analysis of a
Large Planetary Strander
using CAE tools
By Giorgio Pirovano, MFL Group, and Fabiano Maggio, EnginSoft SpA
❍
❍ Figure 1: Rotations on a planetary stranding machine
❍
❍ Figure 2: Single cage of planetary machine
❍
❍ Figure 3: Method and DOE approach
Single cage
Single cage Single cage
Spool dimension
DOE
Load on parts
Motor’s
power
Spool
unbalance
Spool
combination