This dissertation is a validation of previous analytical and numerical investigations into the presence of chaotic instability within a dragline bucket while slewing. Recent investigations have shown the presence of chaotic motion within two separate dragline models. However as these dissertations are currently the only investigations that exist with this field, there is no accurate way to validate their results. Therefore, this analysis aims to validate all previously investigated dragline models through CAD model simulations run in a computer program ADAMS/ View. Furthermore, analysis is taken a step further to investigate the presence of chaotic instabilities within a real world dragline slew.
Meehan and Austin were the first to investigate this phenomenon, showing the existence of chaos through analytic (linearized) and numeric analysis of a simplified dragline model. The model consisted of a pendulum bucket mass suspended from the dragline boom tip, located a fixed distance away from the centre of rotation. Hateley then further developed this model to include the effects of the drag rope and boom inclination angle upon the bucket response. Through similar analysis as used in the previous dissertation, Hateley was also able to show chaotic instabilities for a range of investigated bucket positions. During the 2005-2006 christmas break, Schwarz developed a series of CAD models replicating each of the previous investigations.
Through the use of these CAD models, it was possible to accurately model each of the previous investigations by importing the same design parameters. Through comparative analysis it was shown that the results generated through the CAD simulations coincided very well with those of Meehan and Austin, thus validating their investigation. However, simulated results did not coincide well with those predicted by Hateley's investigation. Analysis of both data sets revealed the possibility of errors within Hateley's analytic investigation. Further analysis was carried out within an advanced CAD model, Dragline_final, which is capable of taking in real world dragline operating data and simulating an accurate dig cycle. Analysis showed a linear system response free from any sign of chaotic instabilities.