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Detection of interface flaws in Concrete-FRP composite structures using linear and nonlinear ultrasonics based
Saptarshi Sasmal1, Sukanya Basu1, Chunduri V V Himakar2
1Special and Multi-functional Structures Laboratory, CSIR-Structural Engineering Research Centre, India; Academy of Scientific and Innovative Research, Ghaziabad-201002, India.
Ultrasonics
|April 30, 2023
Summary
Nonlinear ultrasonic methods effectively detect early-stage flaws in Fiber Reinforced Polymer (FRP)-concrete interfaces, crucial for structural retrofitting integrity. The Sideband Peak Count-Index (SPC-I) technique shows remarkable performance in identifying these critical defects.
Area of Science:
- Civil Engineering
- Materials Science
- Non-Destructive Testing
Background:
- Retrofitting existing structures with Fiber Reinforced Polymer (FRP) composites enhances integrity and sustainability.
- Effective retrofitting relies on the integrity of the FRP-concrete interface, as flaws can compromise structural performance.
- Early detection of interface flaws is critical for ensuring the long-term durability of retrofitted infrastructure.
Purpose of the Study:
- To investigate the efficacy of ultrasonic waves for detecting early-stage flaws at the FRP-concrete interface.
- To compare the performance of linear and nonlinear ultrasonic methods in characterizing interface flaws.
- To evaluate the potential of the Sideband Peak Count-Index (SPC-I) technique for flaw detection.
Main Methods:
- Artificial flaws were introduced into the epoxy layer of carbon-based FRP composite concrete beams.
- Rayleigh waves at 75 KHz and 250 KHz were used to interrogate specimens.
- Linear and nonlinear ultrasonic signal processing techniques, alongside numerical simulations, were employed.
- The Sideband Peak Count-Index (SPC-I) nonlinear ultrasonic technique was specifically assessed.
Main Results:
- Linear ultrasonic methods provided inconsistent information regarding the presence and extent of flaws.
- Nonlinear ultrasonic methods demonstrated superior performance in characterizing both small and large artificial flaws.
- The SPC-I nonlinear ultrasonic technique exhibited high sensitivity and remarkable performance in detecting FRP-concrete interface flaws.
Conclusions:
- Nonlinear ultrasonic methods are more effective than linear methods for detecting flaws in FRP-concrete interfaces.
- The SPC-I technique shows significant promise as a reliable tool for non-destructive evaluation of retrofitted structures.
- Accurate detection of interface flaws using advanced ultrasonic techniques is essential for ensuring structural safety and longevity.
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