Enhanced Software Suite Maximizes Non-Destructive Evaluation (NDE) Methods

materials and coatings
Enhanced Software Suite Maximizes Non-Destructive Evaluation (NDE) Methods (MSC-TOPS-34)
New capabilities boost scope and resolution of Flash Thermography NDE
Overview
Researchers at NASA Johnson Space Center have developed novel techniques for post-processing of flash infrared (IR) thermography data, providing efficient and cost-effective enhancements to Non-Destructive Evaluation (NDE) of structures for numerous applications. Compatible with commercial IR thermography products, this suite of tools provides both quantitative and qualitative data analysis capabilities and reliable detection and characterization of anomalies in composite and some metallic hardware. By adding the Transient Thermography method, which is able to detect flaws on thicker parts faster than other methods, and the Lock-in Thermography method, which uses a sinusoidal power cycle to provide better flaw resolution, the Flash Thermography NDE Technology Suite has expanded its applicability to other commonly used infrared thermography techniques, enhancing operator accuracy and efficiency.

The Technology
This technology provides comprehensive, detailed, and accurate NDE detection and characterization of subsurface defects in composites and some metallic hardware. This complete software suite normalizes and calibrates the data, which provides more stable measurements and reduces the occurrence of errors due to the operator and to camera variability. When using flash IR thermography to evaluate materials, variations in the thermal diffusivity of the material manifest themselves as anomalies in the IR image of the test surface. Post-processing of this raw IR camera data provides highly detailed analysis of the size and characterization of anomalies. The newly incorporated Transient and Lock-In Thermography methods allow the analysis of thicker material and with better flaw resolution than Flash Thermography alone. The peak contrast and peak contrast time profiles generated through this analysis provide quantitative interpretation of the images, including detailed information about the size and shape of the anomalies. The persistence energy and persistence time profiles provide highly sensitive data for detected anomalies. Peak contrast, peak time, persistence time, and persistence energy measurements also enable monitoring for flaw growth and signal response to flaw size analysis. This technology is at a technology readiness level (TRL) of 7 (system prototype demonstration in an operational environment), and the innovation is now available for your company to license. Please note that NASA does not manufacture products itself for commercial sale.
Shown: A Non-Destructive Evaluation Flash Thermography hardware set-up utilizing our advanced software tools.
Benefits
  • Provides enhanced quantitative and qualitative flaw data utilizing a comprehensive software tool suite
  • Quickly extracts and constructs images
  • Compatible with existing flash thermography hardware systems
  • Applies improved signal-to-noise ratio and flaw detection sensitivity
  • Detects anomalies in thicker materials
  • Supports standardization of system components

Applications
  • Aerospace structures and subcomponents
  • Power generation system hardware
  • Chemical and fuel refining components
  • Civil and structural verification
  • Marine and automotive structures and subcomponents
Technology Details

materials and coatings
MSC-TOPS-34
MSC-24444-1 MSC-24506-1 MSC-24506-2 MSC-26052-1 MSC-26358-1 MSC-26359-1 MSC-26359-2
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Guided wavefield techniques require excitation of guided waves in a specimen via contact or noncontact methods (such as attached piezoelectric transducers or laser generation). The resulting wavefield is recorded via noncontact methods such as laser Doppler vibrometry or air-coupled ultrasound. If the specimen contains damage, the waves will interact with that damage, resulting in an altered wavefield (compared to the pristine case). When guided wave modes enter into a delaminated region of a composite the energy is split above/below delaminations and travels through the material between delaminations. Some of the energy propagates beyond the delamination and re-emerges as the original guided wave modes. However, a portion of the wave energy is trapped as standing waves between delaminations. The trapped waves slowly leak from the delaminated region, but energy remains trapped for some time after the incident waves have propagated beyond the damage region. Simulation results show changes in the trapped energy at the composite surface when additional delaminations exist through the composite thickness. The results are a preliminary proof-of-concept for utilizing trapped energy measurements to identify the presence of hidden delaminations when only single-sided access is available to a component/vehicle. Currently, no other single-sided field-applicable NDT techniques exist for identifying hidden delamination damage.
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