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Saturday, October 1, 2005

NDT - Medical Technology Enhances GE NDT

Vicki P. McConnell

When Genenal Electric saw a need to offer its customers more advanced NDT (non-destructive testing) solutions, it found many of the answers for such products within its own suite of businesses. Realizing that technologies developed and used in businesses such as GE Healthcare had applicability for aviation and other industries, GE decided to expand its NDT offering via a dedicated business unit.

In 2004, GE acquired AGFA NDT and combined it with GE Aircraft Engines’s existing NDT business to form GE Inspection Technologies (GEIT). Later in 2004, Hocking NDT was acquired for its hand-held and small footprint eddy current products. Jeff Nagel, president of GEIT, explained that the strength of the NDT products and experience from these combined NDT businesses, plus the leveraged business technologies from GE Healthcare, provided the solutions its customers were seeking.

“More importantly,” Nagel added, “we’ve gained the engineering expertise of people with real-world industrial experience, as well as a worldwide distribution and service capability that exceeds what we had before.” GEIT industrial engineers now help determine the best use of NDT to boost productivity and quality in the manufacture of GE’s aircraft engine components, whether metal or composite.

General Electric Aircraft Engines is the first and only engine OEM to offer composite fan blades in those primarily metallic engines. The composite blades were introduced in 1995 on the GE90 fan and continue in the design of the GEnx engine model for Boeing’s latest commercial aircraft, the 200-plus passenger “Dreamliner” 787, an aircraft with 50 percent composite materials by weight, including the airframe (see AM cover story, May 2005).

Francois-Xavier Louis, GE’s market segment manager for aerospace, noted that NDT inspection is critical for metal forgings on rotating disks and composite fan blades. Because it can take up to 30 hours to perform a complete multizone inspection of metal forgings after manufacture, Louis said that “this can create a phenomenal bottleneck in our customers’ inspection schedules. So we combined our high-end medical scanner expertise with software and large-array sensor development in order to release to market our LOGIQ 9NDT, the only phased-array system in the world qualified to perform engine disk inspections.”

For composite structure, GEIT’s 128-element phased-array UTXX ultrasound system is a key productivity enabler for composite large-area inspection, such as fuselage or wing sections, where the risks of delamination, porosity, and wrinkles may occur after bonding and forming. Such defects form sound echos during ultrasonic inspection. The technical challenges to design of this array were threefold:

  • Providing a wide enough array for sufficient surface coverage.
  • Combining data collection and analysis with a mechanical system that moves a sensor at a decent speed while coping with complex surface geometries such as radii and corners.
  • Building an imaging software package that displays the information in a user-friendly manner.

The UTXX system, combined with GEIT’s Nuscan imaging software, successfully addresses this challenge. “Today,” Louis said, “ we shoot 4,000 times per second, moving our 100-millimeter-wide UT probe at 2.4 meters per minute. Despite achieving world class productivity standards, our technical teams are working to further increase speed.”

Nagel added that GEIT is developing bonded ultrasonic sensors for composite structure. “These sensors would be ever-present and gather real-time feedback. Such technology could raise everyone’s confidence level in composite structure and offer airline pilots and maintenance teams more confidence by looking at this ahead of time.”

Mindset for composites

Louis believes that “there will be a shift in mentality regarding more composites on aircraft, to a more matter-of-fact acceptance as we have now with metal. Our job as an NDT supplier is to be sure we are ahead of that shift, providing technology to assure the safety of any composite part that goes out in the aircraft market.” Though the first of Boeing’s 787s won’t fly until 2007, Louis suggests that the OEM and operators will need inspection and repair scenarios on the shelf for that aircraft well before first flight.

Composites training must also be further developed; NDT training is an existing GEIT capability, and Louis is working with the entire team to understand exactly what goes into a composites training package that will answer the needs of those who do the NDT inspections in the real world. “Composites by their very nature and newness require training,” he said. “We are currently working with our customers to define specific training needs along with inspection technologies for the aerospace OEM and maintenance worlds.”

Developing NDT modalities proactively and putting technical support as close at hand as possible is the aim of GEIT applications centers in Shanghai (China), Cologne, Hamburg (Germany), Lyon (France), Brussels (Belgium), Coventry, St. Albans (U.K.), Lewistown, Cincinnati, and Houston (U.S.). Nagel concluded that GEIT’s proactive approach and expanded suite of NDT products “can help reduce non-value added time, scrap, and even shipping costs. On the service side, accurate NDT can extend the life of the aircraft asset.”

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