Demonstration of a Dragline Boom Strengthened With Pre-impregnated Composites

Fatigue cracking in structural members is one of the primary causes of unscheduled downtime in mining equipment. The boom-mast structural system of draglines is vulnerable to fatigue failures. In order to maintain or improve operational reliability and availability throughout the service life of the structures, efficient and effective methods of minimising fatigue damage and crack repair must be developed. The ACARP project C17028 is the natural extension of ACARP project C16028, where a suitable composite system with site curing capability has been tested in the laboratory for its suitability and basic engineering properties and characteristics.  The objectives were:

· To demonstrate a composites material strengthening to a steel dragline boom;

· To monitor the structural effectiveness of the strengthening; and

· To evaluate the cost effectiveness of the strengthening method.

The application site was a Bucyrus 1370W model Dragline which is Unit 105 for Hunter Valley Operations (HVO) mine. Based on the results from the project C16028, a 2m long section of boom lacing (steel pipe) 8.625'' (219mm) Diameter and 0.32'' (8.18mm) wall thickness was utilized to have the composite material applied as part of this trial. The effectiveness of the strengthening has been verified by strain gauges fixed onto the steel before and after the composites application.  This report is laid out according the following structure:

· A brief state of the art;

· The application choice;

· The strengthening design;

· The onsite composites application;

· The strain gauging results;

· A cost effectiveness analysis.