WCA September 2016

Design Analysis of a Large Planetary Strander

using CAE tools By Giorgio Pirovano, MFL Group, and Fabiano Maggio, EnginSoft SpA

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.

Single cage

Single cage

Single cage

❍ ❍ Figure 2 : Single cage of planetary machine

Spool dimension

Spool combination

DOE

Spool unbalance

Motor’s power

Load on parts

❍ ❍ Figure 1 : Rotations on a planetary stranding machine

❍ ❍ Figure 3 : Method and DOE approach

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.

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Wire & Cable ASIA – September/October 2016