This electronic brochure highlights our capabilities and activities in the area of NDE Research & Materials Characterization. Please sign our guestbook. For additional information, e-mail Dr. Glenn M. Light, Southwest Research Institute.

NDE Research and Materials Characterization

The development of nondestructive evaluation (NDE) methods used in quality management and reliability maintenance systems is a major research activity at Southwest Research Institute (SwRI). Technical activities focus on developing front-end information collection devices, determining relationships among material properties and physical measurements, and assessing equipment and products during fabrication and use.

Scientists apply a pump-shaft ultrasonic inspection system, developed by SwRI for the Electric Power Research Institute, to a pump-shaft mock-up.

Institute scientists evaluate a nonlinear harmonics technique for measuring stress in railroad rails.

Principal Program Areas

Damage Assessment

For corrosion, impact, creep, and hydrogen attack

  • Materials: metals and composites
  • Approach parameters: thickness, velocity, scattering measurements; sensitized coatings; etc.
  • NDE methods; ultrasonic (UT), eddy current (ET), shearography, thermal, X-ray radiography, nuclear magnetic resonance, magnetically induced velocity change, and acoustic emission (AE) testing, etc.

Isolated Flaw Assessment

For voids, cracks, inclusions, and lack of adhesion

  • Materials: metals, composites, and ceramics
  • Approach parameters: defect detection, sizing, classification, growth monitoring, etc.
  • NDE methods: UT, ET, magnetic and electric current perturbation, radiography, thermography, optical sensing, AE, etc.

Structural Integrity Inspection and Monitoring

For fracture, fatigue, residual stress, and long-term degradation in highway bridges

  • Materials: steel, reinforced prestressed concrete, wire rope, and strand
  • Applications: defect detection, location, sizing classification, growth monitoring, and long-term global monitoring
  • NDE methods: UT, AE, ET, transverse/impulse magnetic flux leakage, "smart" sensors, etc.

Materials Characterization

For density variations, poor bonding, hardness, stress levels, interstitial oxygen, and coating variations

  • Approach parameters: velocity, scattering, thickness, magnetic properties, etc.
  • NDE methods: UT, ET, thermal, radiography, Barkhausen, magnetically induced velocity change, nonlinear harmonics, reversible permeability, etc.

Processing and Component Assessment

For automatic welding and cutting, pipeline welding, transfer, underwater testing, and weld location

  • Approach parameters: edge location and orientation, surface features, velocity, etc.
  • NDE methods: UT, optical sensing, thermography, ET, etc.

Color imaging of nonlinear harmonics data provides rapid visualization of stress patterns in steel, such as the residual compressive stress from shot peening shown here in blue.

Capabilities

Ultrasonics

  • Pulse echo/through transmission
  • Immersion/contact/booted
  • Transducer design, fabrication, and certification
  • C-scan/B-scan
  • Schlieren imaging
  • Color-imaging generation
  • Noncontact magnetostrictive transducers

An SwRI-developed tread material used on this ultrasonic wheel allows ultrasonic energy to be coupled into steel without liquid at frequencies as high as 5 MHz.

SwRI uses a magnetostrictive "smart" sensor system, shown in this artist's rendition, to determine long-term structural degradation of reinforced concrete bridge beams.

Stress Measurement

  • Barkhausen noise techniques
  • Magnetically induced velocity-change techniques
  • Nonlinear harmonics
  • Reversible permeability
  • Hole-drilling techniques
  • Strain gauge measurements

Combining ultrasonic (top) and eddy current (bottom) imaging of a small, identical near-surface defect in a cladded material, SwRI greatly improves its overall probability of flaw detection.

Electromagnetics

  • Eddy current
  • Remote field eddy current
  • Pulse eddy current
  • Electric current perturbation
  • Computer modeling
  • Reliability studies
  • Specialized procedure development
  • Specialized NDE system development
  • Color-image generation
  • Position and orientation sensing

Magnetics

  • Magnetic perturbation/flux leakage
  • Magnetic properties characteristics
  • Modeling
  • Computer-aided tomography

SwRI innovations to a retirement-for-cause inspection probe head allow all inspections to be accomplished by one probe rather than nine. Calibration time is reduced from 80 to 10 minutes.

Radioisotope and Radiation Applications

  • Gauging
  • Real-time radiography
  • Activation analysis
  • Neutron radiography
  • Radioisotopic tracers

Thermography

  • Thermal imaging
  • Thermal wave detection

Acoustic Emission

  • Flaw initiation and growth
  • Loose parts monitoring
  • Flaw location
  • Noncontact magnetostrictive transducers

Computer Modeling

  • Ultrasonic beam model to develop special transducers needed to produce specific focused beams in materials
  • Ultrasonic transducer fabrication model to specify components required to fabricate a transducer for a given inspection
  • Eddy current probe model for developing specialized eddy current probes
  • Eddy current flaw model to predict the influence of various defects on the eddy current field

This SwRI-developed eddy current inspection system uses a three-axis scanner to inspect the small blades of the space shuttle's auxiliary power units.

An Institute-developed inspection system examines a cylindrical battery intended for space station service. The system employs eddy current testing for most exterior and interior surfaces and ultrasonic testing for volumetric inspection of welds.

Laboratory Facilities and Equipment

Facilities include 7,400 square feet of space fully equipped with a wide range of laboratory and field instrumentation, including:

  • Computer-controlled scanners and data acquisition systems
  • Large variety of ultrasonic and eddy current instruments
  • AFGA thermovision camera
  • HP4194A impedance analyzer
  • Real-time X-ray cabinet
  • Conventional and digitizing scopes
  • Spectrum analyzer
  • Schlieren system
  • Fiber-optics microbench and microinterferometer
  • Optical table
  • Transducer characterization station
  • Shearography system
  • Thermography system

SwRI's ultrasonic laboratory provides instrumentation and facilities for NDE research and development.

SwRI technicians design and fabricate ultrasonic and eddy current sensors in the sensor development laboratory.

A transducer beam evaluation is performed in the SwRI Schlieren laboratory.

The electromagnetic NDE laboratory is used for eddy current, pulsed eddy current, and magnetic perturbation testing.
This brochure was published in September 1995. For more information about NDE research and materials characterization, contact Dr. Glenn M. Light, Nondestructive Evaluation Science and Technology Department, Mechanical Engineering Division, Southwest Research Institute, P.O. Drawer 25810, San Antonio, Texas 78228-0510, Phone (210) 522-2949, Fax (210) 522-4822.

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