An investigation into increasing the fatigue life of an electric shovel dipper handle

van Rensburg, Henriette Janse (2017) An investigation into increasing the fatigue life of an electric shovel dipper handle. [USQ Project]


One of the key contributors to the Queensland economy is the coal mining industry that contributes employment and provides billions of dollars per annum operating costs of open cut mines that are cheaper than underground mines and are therefore, more common within Australia for uncovering and mining coal. In these open cut operations, electric rope shovels are the most important part of the coal uncovering and mining process, after draglines. The average fatigue life of electric shovel dipper handles is estimated at 12 000 hours. Thus, fatigue of electric shovel dipper handles contributes significantly to the cost and efficiency of open cut coal recovery. The main research problem of this study was to explore/investigate increasing the fatigue life of electric shovel dipper handles. The project investigated the failure modes of a P&H 4100 shovel dipper handle in order to make recommendations on ways to increase the fatigue life of the dipper handles. The study found that the two most prominent failures of the shovel dipper handles were cracking in the internal diaphragms and adhesive wear. In order to extend the fatigue life options/mechanisms to reduce fatigue were investigated. Literature review was conducted and the information gathered was used to inform understanding of the operation of dipper handles currently used in the mining industry. The project consisted of three phases, namely analyse, test and redesign. It included both quantitative and qualitative data. The first phase included the collection of quantitative and qualitative data on shovel dipper handle performance. Data was obtained from maintenance records and confidential reports from previous shutdowns. Additional qualitative data was collected during semi-structured interviews with shovel operators and shutdown project managers. Observations were also made during site visits. The second phase incorporated the testing/simulation of the current dipper handle design for fatigue failure using FE modelling and analysis. Manual hand calculations were used to validate the FEA modelling. The third phase incorporated design changes to increase fatigue life based on response to the results obtained from the second phase. In the third phase, the second and third phases were interlinked and were applied continuously until the final redesign was reached. The FEA models showed that the dipper handle designs were capable of handling the two different loading conditions simulated in Autodesk. As these loading conditions represented worst case scenarios, it is suggested that the dipper handle designs would be suitable for normal daily operations. The new design increased the overall dipper handle weight by 2.86 tonne, however, this will not affect the overall performance of the electric shovel. The estimated fatigue life of the new dipper handle design, ranged from 990 000 cycles to 1 000 000 cycles, compared to the current fatigue life of 420 000 cycles to 500 000 cycles. This indicated a significant increase in fatigue life of the dipper handles of 42 percent.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Honours)(Mechanical)
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021)
Supervisors: Snook, Chris; Fry, Ryan
Date Deposited: 08 Sep 2022 03:00
Last Modified: 08 Sep 2022 03:00
Uncontrolled Keywords: electric shovel dipper handles; fatique life

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