Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

Selectively Exposed Embedded Acoustic Waveguide Sensors For Guided Wave Based Online Monitoring of Rheology Changes and Damage/Defect Thereof

Technology Category/Market

Technology: Acoustic Waveguide Sensors For Guided Wave Based Online Monitoring of Rheology Changes and Damage/Defect

Category: Non-Destructive Testing Methods & Equipment (NDT/NDE)

Industry: Material Inspection Industry

Application: Composite testing

Market: The global market size was USD 14.28 billion in 2022 and is projected to grow from USD 15.78 billion in 2023 to USD 33.73 billion by 2030, exhibiting a CAGR of 11.5% during the forecast period.

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Problem Statement

  • Composites are widely used in Civil, Aerospace, and Mechanical Industries due to their strength relying on bonding layers.
  • Inspection of composites is challenging due to multiple layers, anisotropic nature, time, and complex structure features. Non-Destructive Technologies (NDTs) like Ultrasonic Guided Waves are widely used for inspection, as they can inspect large areas quickly and effectively detect defects.
  • However, current NOE techniques for structural health monitoring use omni-directional wave transduction via surface bonded transducers, which generate cylindrical waves that decay away from the source, limiting the applicability of ultrasonic guided waves due to attenuation over distance.

Technology

  • A system for guided wave based online monitoring of rheology changes, damages and defects in a structure using selectively exposed embedded acoustic waveguide sensors, comprising of:
  • one waveguide sensor embedded into the inter-laminar region of a composite structure, one end of the embedded waveguide is protruded out from the structure,
  • a coating surrounding the waveguide coating prevents leakage of waves into the surrounding structure and ensures one dimensional plane wave generation and energy distribution inside the structure through much longer distance;
  • one sleeve opening on the waveguide sleeve receives reflections of wave energy from various places inside the structure;
  • one probe attached to a pulser receiver, converts the electrical energy from the pulser receiver to mechanical vibrations using a piezoelectric crystal, which is transmitted into the waveguide in the form of ultrasonic waves.

Method:

  • Guided Wave-Based Online Monitoring of Structure Rheology
  • Generates guided ultrasonic wave modes using an ultrasonic transducer.
  • Transmits these modes along the waveguide, interacting with the structure.
  • Recorded reflected wave signals using an ultrasonic transducer and instrumentation.
  • Detects crack/delamination in the structure by calculating wave energy leakage and reflection.
  • Determines the location of crack/delamination by calculating the time of flight of reflected wave signals.

Key Features/Value Proposition

Composite Structure Delamination/Crack Detection:

  • Provides reference signal.
  • Ensures integrity of composite structures.

Wave Energy Calculation:

  • Determines delamination/crack location.
  • Calculates time of flight.

Waveguide & Sleeve Opening:

  • No airgap between waveguide and sleeve.
  • Removes coating for sleeve opening.

Waveguide Shapes and Sensor Types:

  • Circular, cylindrical, tubular, elliptical, square, rectangular.
  • Longitudinal, Torsional, Flexural.
  • Anti-Symmetric, Symmetric, Shear Horizontal.

Waveguide Coating Overview:

  • Polymers, paper, or heat shrink polyolefin.
  • Pulser receiver connected to digital oscilloscope.

Wave Signal Reception Process:

  • Receives one wave signal without delamination/crack.
  • Receives two wave signals with second reflection from structure.
  • Reflects second signal to waveguide sensor and receiver probe.

Wave Mode Generation in Piezoelectric Crystals:

  • Dependence on relative crystal position.
  • Guided waves generated via piezoelectricity, electromagnetic transduction, or Thermal Mechanisms.
Questions about this Technology?

Contact for Licensing

Research Lab

Prof. Krishnan Balasubramaniam

Prof.Prabhu Raja Gopal Department of Mechanical Eng.

Intellectual Property

  • IITM IDF Ref. 1435

  • Patent No: IN 373496

Technology Readiness Level

TRL 3

Experimental Proof of Concept

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