FORCE Technology: Revolutionary Blade Inspection

Still being a rather manual layup and assembly process, variability in quality is a key issue for the ultimate blade performance.

Automated ultrasonic inspection systems have been successfully applied for a number of years. They follow a continuous evolution, from uncomplicated manual inspection systems, to more advanced track scanner and crawling scanner concept. The concept with autonomous scanner systems has also been exploited recently. They are based on a mobile self-propelled truck chassis, carrying scanner mechanics, cranes, ultrasonic probes and required control units for data handling and physical manipulation.

Vertically oriented blades

Non-destructive inspection (NDI) on vertically oriented rotor blades has been a request for some of years. The evolution has also brought a couple of scanner systems of this nature to the market. In 2014 FORCE Technology proudly announced a revolutionary inspection concept, based on the Mobile Blade Array Scanner [AMS-71]. It is equipped with a unique full size 24 channel probe array (Fig 1), collecting NDI data in a multiple line-scan mode. P-scan multi-channel electronics and software may record, collect and analyze scanning data from the load-bearing spar cap and the adhesive bonding to internal shear webs.

Fig 1. The 24 channel Probe Array.

Fig 2. The Mobile Blade Array Scanner.

Inspection speed

The greatest revolution comes from the inherent performance of the Mobile Blade Array Scanner. Simultaneous multi-channel data handling allows for an unbeaten high linear inspection speed, reaching 5-7 meter per minute (Fig 2). All is obtained with a pre-determined resolution for detection of hidden flaws.

The capacity for full spar cap inspection on 60-80 meter long rotor blades is within 60 minutes, both blade sides covered. Another advantage is that only one single UT inspector is required to operate this revolutionary mobile blade array scanner. Keeping the line scan principle in mind, the accuracy for monitoring and sizing of any UD fiber waviness (wrinkles) is excellent. This is not compromising the ability for full and accurate bond-line assessment. Data on any embedded spar cap structure will be included without extra work.

Video link: https://www.youtube.com/watch?v=_zqWag2E-hM

Future prospects

There is a fortunate trend in the blade industry to consider and invest in selective automation in various steps during blade manufacture:

• Fiber layup, for the basic FRP composite shell and web components.

• Infusion and molding of the basic FRP composite blade shell and shear web components.

• Adhesive bonding of the complete assembled rotor blade.

• Finishing, with grinding and painting.

The shown Blade Array Scanner concept may quite easily be adapted to contemporary automated robot systems, to accommodate the full capacity for an integrated system approach. When the industry is ready for this expansion in future automated technology, the required advanced NDT inspection technology is already available.
 

FORCE Technology

Company FORCE Technology is an independent leading technological consulting and service provider internationally. The target is to offer highly specialized engineering know-how that delivers useful and efficient testing solutions to the wind energy industry.

Solutions we provide enhance customer’s competitiveness and are based on both customer and industrial insight, that we have acquired over 25 years in wind energy business. That alone makes FORCE Technology the market leader in integrated systems for automated quality inspection on rotor blades.

We are currently around 1.300 employees, located at the head-quarters in Brondby and with subsidiary companies and multiple local offices in Sweden, Norway, Russia, China, Singapore and the USA.