Laser Ultrasonic Inspection of Materials and Structures

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The Industrial Materials Institute (IMI) of the National Research Council of Canada (NRC) is developing forefront laser ultrasonic technology for probing materials and structures remotely without contact.

Technology

This novel technology is based on the use of lasers for the generation and detection of ultrasound and can be used to:

• measure thicknesses
• detect and image surface or bulk flaws in complex structures
• characterize material microstructure in service or during processing

Being a technique based on optics, laser-ultrasonics can operate at considerable standoff distances from the probed part (several feet). As a consequence, parts can be readily tested at elevated temperatures, in vacuum, etc.

Generation and detection of ultrasounds are performed from the surface of the part, independently of its shape and orientation. Hence the requirement for near-normalcy of conventional ultrasonic transducers is eliminated and complex shapes can be rapidly inspected and imaged with a simple scanning system.

The technology has been demonstrated in manufacturing plant floor and production line conditions.

Applications

Laser-ultrasonics is very generic and can be applied to metals, polymers, ceramics and composites (metal or polymer matrix). Examples of applications performed by IMI include:

• determination of elastic constants on ceramics and ceramic-metal composites up to 1800°C (3300°F)
• wall thickness measurement of seamless tubes at 1000°C (1800°F) moving 12 feet per second directly on the production line
• inspection of numerous parts with complex contours made of polymer matrix composites (laminates, honeycomb structures, bonded parts)
• detection of lap joint corrosion in an aluminium airframe
• grain size and texture measurement in steel sheet
• inspection of the composite airframe of an aircraft without preparation and detachment of any part in a maintenance facility

Facilities Available at IMI

IMI has a wide variety of equipment which allows experimentation on virtually any material, or parts of any shape and at any temperature, more specifically:

• generation lasers (solid state Nd-YAG, excimer, pulsed carbon dioxide) to allow optimum generation of ultrasound on a wide variety of materials and coatings
• sensitive detection hardware including several high power detection lasers and interferometric probes of various kinds, several of them being unique, permitting coverage of a frequency range from 1 kHz to several hundred MHz
• digital sampling electronics, with rates extending to several GHz, associated with advanced signal processing
• optical scanning devices making it possible to easily generate images
• several furnaces for ultrasonic measurements at high temperature, up to 2600°C (4700°F)

Industrial Collaboration

IMI strongly encourages collaboration. The Institute can perform work ranging from a simple measurement or feasibility study in its laboratories to full scale demonstration in your production plant or in the field.

Information

To learn more about laser-ultrasonics and other technologies in order to benefit from NRC's R&D resources and give your firm a technological advantage, please contact IMI representatives.

Dr. Jean-Pierre Monchalin Group Leader, Optical Techniques Modelling and Diagnostics Section Tel. : (450) 641-5116 Fax : (450) 641-5106 E-mail: Jean-Pierre.Monchalin@cnrc-nrc.gc.ca
Ngoc Huynh, Eng., M.A.Sc., M.B.A. Business Development Officer Modelling and Diagnostics Section Tel. : (450) 641-5135 Fax : (450) 641-5106 E-mail: Ngoc.Huynh@cnrc-nrc.gc.ca

Related Information

Institutes:

• NRC Industrial Materials Institute