Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Time Delay Focusing of Ultrasonic Array Transducers on a Defect Using the Concept of a Time Reversal Process

  • Jeong, Hyun-Jo (Division of Mechanical and Automotive Engineering, Wonkwang University) ;
  • Lee, Jeong-Sik (Division of Mechanical and Automotive Engineering, Wonkwang University) ;
  • Lee, Chung-Hoon (Division of Semiconductor and Display Technology, Wonkwang University) ;
  • Jun, Ghi-Chan (Picosonic Inc)
  • Published : 2009.12.30
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Abstract

In an application of a time reversal(TR) focusing of array transducer on a defect inside the test material, we employ a new time delay focusing technique based the TR process. In order to realize this idea, a multi-channel ultrasonic system is constructed capable of applying necessary time delays to each channel. The TR-based focusing procedure first measures the backscattered signals after firing one of the array elements. A phase slope method is then used to determine the time-of-flights of the backscattered signals received by all elements of the array. These time delays are used to adjust the time of excitation of the elements for transmission focusing on the defect. In addition to the TR focusing, the classical phased array focusing is also considered for comparison. Experimental results show that the TR-based time delay focusing produces much stronger backscattered signals than the phased array focusing, demonstrating the enhanced capability of the TR focusing.

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References

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