Tub Specification, Design, Inspection and Auditing
Dragline tubs or bases are the foundation of the machine and although they are tolerant of quite extensive damage, maintenance is difficult and can be minimized with good design. As large walking draglines have been in operation around the world since the early 1970’s (and in small numbers well before that) there is considerable history.
Using a combination of analytical stress analysis, historical performance of various tub designs and weld fatigue principles CMP Engineers has developed specifications, undertaken design audits, executed design modifications, provided QA advice during manufacture and inspected operational tubs for remnant life and maintenance strategies for several draglines.
Specific projects include: Marion 8050 and BE 1370W new tub specifications, stress analysis of a proposed cable entry modification to reduce handling of the connector/plug, review of the OEM proposed bolting arrangement on a new rack, risk analysis and maintenance strategy for extending the life of operating tubs.
Structural Analysis of Dragline Boom
CMP Engineers has also used FEA modelling programs to perform a structural analysis of dragline booms to determine highly stressed lacings and clusters and to identify any members prone to buckling. Structural members are also checked for compliance against AS3990 and AS4100.
Miscellaneous dragline, shovel and excavator design, analysis and upgrade projects.
Fatigue failures continue to occur on the structures and machinery of draglines, shovels and excavators. CMP Engineers has undertaken failure analysis, re-design and design audit work on many components in this type of equipment using our knowledge and thorough understanding of weld fatigue and stress analysis.
Projects include the design review of an OEM boom point swivel beam following failure in service, stability analysis of dragline for walking without the boom point sheaves, and the design audit of a shovel hoist drum proposed to replace the OEM part which had experienced multiple failures.
Other projects include the design of support structures for new ventilation modules on the roof of the machinery house including a capacity review of the machine house steelwork, design of corner reinforcement for jacking the revolving frame of a dragline and investigating the failure of a motor shaft.