JEC COMPOSITES MAGAZINE - Issue #65 - May/June 2011 - 46

NDT

Fig. 2: Portable shearography system for boat inspection Fig. 3: Portable shearography system on curved surfaces

Fig. 4: Automatic shearography system with robot

are taken into account for inspection performance. For flat parts such as wind turbine blades, a different concept is adopted due to the extremely large surfaces and specific areas requiring specific attention. While the shearography system remains the same, the peripheral equipment needs to be adapted.

Certification
Shearography technology reached a fundamental milestone in industry acceptance in 2006 when it was included in ASNT SNT-TC1A for Level III shearography certification. Over 300 NDT professionals have received shearography NDT training to ASNT Level II. Since 2008, shearography has also been incorporated in the Standard Document, NAS 410, 2008 Rev 3, which is used for EN4179 European certification.

applied. Debondings or other defects will show up in typical deformation patterns (Figure 1 and 5). An integrated touch-screen displays the inspection results and enables the operator to work on scaffolds or inside openings. Typical inspection time is less than 30 seconds per image. One image covers approximately 220 x 180 mm . These inspection systems, which offer remarkable high test repeatability, are currently used for field inspections in many sectors, such as the aircraft, wind energy and boating industries (Figures 2 and 3).

Automatic shearography inspection systems

The composite manufacturing sector is constantly developing automated production lines. In keeping with this trend, robotic shearography equipment is also available as a standard industrial

jec composites magazine / No65 May –June 2011

system. This equipment is capable of inspecting up to 2 m per minute for arbitrary geometries, which is absolutely cutting-edge performance for non-destructive testing (NDT) worldwide. The system operates in the production environment inside a vacuum chamber. Production parts are excited by the vacuum and can also be loaded with up to 3 kW of heat if necessary. The objects are illuminated Conclusion by 8 laser diodes and the shearography Shearography provides major sensor reads out phase stepping results advantages in non-destructive in real-time (Figure 4). The system’s inspection (NDI) as it is a very flexible interface is designed for easy operation and fast inspection method. It has the and harmonization with a company’s unique potential of detecting specific written practice standard, in defect types in composite materials compliance with the SNT-TC-1A such as wrinkles in wind turbine blades standard or similar. The robot system (Figure 5), both in production and incan also be equipped with a softwarefield applications. n More information: integrated sound excitation mode for www.dantecdynamics.com vibration shearography using a piezoelectric shaker or speaker. Automatic shearography inspection systems are generally adapted to customer specifications, as part geometries, production environment defect thresholds and other parameters may vary substantially, and different challenges Fig. 5: Wrinkles shown using shearography

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JEC COMPOSITES MAGAZINE - Issue #65 - May/June 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #65 - May/June 2011