When a seven metre portion of a Vestas blade prototype broke off last year – only weeks after the company had a signed a deal to supply the same model to a 420MW wind farm in Australia – the company felt it had some explaining to do. But according to the latest Wind Energy Update Operations and Maintenance Report 2011, human error, which was ultimately the cause of the failure, is all too common in blade prototype manufacturing.
“The rotor blade prototype fabrication process requires significant hand labor, providing abundant opportunity for deviations to the fiber placement specifications,” explains the report, which provides an in-depth cradle to grave analysis of blade design, manufacture, and maintenance.
For its part, Vestas noted that manually produced prototypes engender a higher risk of failure than those produced by automated production processes. But it was quick to add that the failure of its V112-3.0 prototype would “not be possible in Vestas’ automated manufacturing process”.
The report’s authors concur. “Automation of the process promises to shorten the cycle time, document the process, increase repeatability, and reduce opportunities for human error”.
Beating the odds
Moving beyond the prototype and into full-scale production, however, does not shield the blade from a myriad potential production hazards, warns the report. For example, the very presence of composite and sandwich materials in wind turbine blades makes them prone to structural instabilities such as buckling and wrinkling.
