• 한국수산과학회지
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• 제54권6호
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• pp.1036-1044
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• 2021

A linear array acoustic transducer with 12 tonpilz elements mounted independently on a gradual wedge-shaped tail mass was fabricated, tested and analyzed. The compensated transducer, which is modified by including a series inductance of 137 µH in the developed linear array transducer, attained improved figure of merit (FOM) performance characteristics compared with the uncompensated transducer. The four resonant frequency bands were identified from the measured FOM curve. The FOM response patterns over the frequency ranges of 31 to 40 kHz and 50 to 60 kHz were relatively uniform, whereas sharp resonance peaks were observed at around 73 kHz and 84 kHz. These results indicate that the developed linear array transducer can be used as an enhanced broadband transducer of echo sounder, and the operating frequency can be selected for more effective echo surveys in the fishing ground.

• 소음진동
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• 제10권1호
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• pp.123-128
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• 2000

This paper describes the optimization of the hexagonal array transducer using finite element method. The transducer consists of the disc type sensors. Three dimensional beam patterns of each element and the array transducer are analysed using the finite element code ATILA. Beam patterns were analyzed for the disc type transducer. To optimize beam patterns of the array transducer, Chebyshev polynomial weight is applied to each element. In case of applying optimized weight, a 30 degree width beam pattern is presented at 10kHz. This paper also includes the effect of rubber filling material instead of using the water inside the transducer array.

• 비파괴검사학회지
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• 제34권6호
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• pp.441-446
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• 2014

A 3D ultrasound image is desired in many medical examinations. However, the implementation of a 2D array, which is needed for a 3D image, is challenging with respect to fabrication, interconnection and cabling. A 2D sparse array, which needs fewer elements than a dense array, is a realistic way to achieve 3D images. Because the number of ways the elements can be placed in an array is extremely large, a method for optimizing the array configuration is needed. Previous research placed the target point far from the transducer array, making it impossible to optimize the array in the operating range. In our study, we focused on optimizing a 2D sparse array transducer for 3D imaging by using a simulated annealing method. We compared the far-field optimization method with the near-field optimization method by analyzing a point-spread function (PSF). The resolution of the optimized sparse array is comparable to that of the dense array.

• Smart Structures and Systems
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• 제21권6호
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• pp.761-776
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• 2018

Guided wave testing is a reliable and safe method for pipeline inspection. In general, guided wave testing employs a circumferential array of piezoelectric transducers to clamp on the pipe circumference. The sensitivity of the operation depends on many factors, including transducer distribution across the circumferential array. This paper presents the sensitivity analysis of transducer array for the circumferential characteristics of guided waves in a pipe using finite element modelling and experimental studies. Various cases are investigated for the outputs of guided waves in the numerical simulations, including the number of transducers per array, transducer excitation variability and variations in transducer spacing. The effect of the dimensions of simulated notches in the pipe is also investigated for different arrangements of the transducer array. The results from the finite element numerical simulations are then compared with the related experimental results. Results show that the numerical outputs agree well with the experimental data, and the guided wave mode T(0,1) presents high sensitivity to the notch size in the circumferential direction, but low sensitivity to the notch size in the axial direction.

• 소음진동
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• 제8권4호
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• pp.663-669
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• 1998

In this paper, a beam design method is presented for the planar array with unequal transducer sensitivities. Basically the proposed method consists of two steps. At first, the optimum weightings are designed with the assumption that all array elements have an uniform sensitivity. Next, the compesnated weightings for the unequal transducer sensitivities can reversely be determined from an inverse problem utilizing the design beam pattern evaluated by the predetermined optimal weightings. A numerical example is inculded to illustrate the proposed method.

• 전기학회논문지
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• 제66권4호
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• pp.629-635
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• 2017

Free-Flooded Ring (FFR) transducer array for use in Sonar system can be driven with large amplitude in a wide frequency band due to its structural characteristics, in which two resonances of a ring mode (1st radial mode) and an inner cavity vibration mode occur in a low frequency band. Since its sound wave generation characteristics are not influenced by the water pressure, the FFR transducer array is widely used in the deep sea. So FFR has been recognized as a low-frequency active sound source and has received much attention ever since. In order to utilize the FFR transducer array for SONAR systems in military and industrial applications, its equivalent electric circuit model is necessary especially to design the matching circuit between the driving power amplifier and the FFR transducer array. Thus this paper proposes the equivalent electric circuit model of FFR transducer array by using measured values of parameter, and suggest the improved method of parameter identification. Finally it verifies the effectiveness of the proposed circuit model of FFR transducer array by experimental measurements.

• 한국음향학회지
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• 제34권2호
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• pp.117-129
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• 2015

파라메트릭 어레이(parametric array)는 매질의 비선형성을 이용하여 고지향성 저주파를 발생시키는 현상이다. 발생된 저주파는 직접 발생된 1차 음파에 비해 음압이 상대적으로 매우 작다. 따라서 강력한 1차 음파를 지향성 있게 발생시킬 수 있는 트랜스듀서가 필수적으로 요구된다. 본 논문에서는 파라메트릭 어레이를 위한 음원으로써 다공진 트랜스듀서의 설계, 제작, 시험평가에 대해 연구하였다. 유닛 트랜스듀서 및 배열 트랜스듀서의 설계를 해석 모델에 근거하여 수행하였으며, 이 과정을 반복하여 최적의 트랜스듀서를 제작하였다. 제작된 배열 트랜스듀서는 6.3 m 거리에서 각각 189 dB, 190 dB의 1차 음파를 확인하였으며, 파라메트릭 어레이 현상을 이용하여 136 dB의 차주파수음 발생을 확인하였다. 차주파수음은 $12{\times}18{\times}10m$크기의 수조에서 15 kHz, $8^{\circ}$ half power beamwidth의 고지향성 저주파 특성을 가지고 있음을 확인하였다.

• 한국음향학회지
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• 제22권8호
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• pp.629-636
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• 2003

의료용 초음파 진단 장치나 표적을 탐지하는 소나 등에 사용되는 초음파 트랜스듀서 어레이는 정도 높은 정보를 얻기 위해 목적에 맞는 지향특성이 요구되어진다. 본 연구에서는 사용 목적 따라 지향 특성을 가변할 수 있는 초음파 트랜스듀스 어레이를 제안하였다. 제안한 초음파 트랜스듀서 어레이는 전기적 용량으로 제 2 차 모드의 효율을 제어할 수 있는 2층 구조 트랜스듀서를 이용하여 트랜스듀서 어레이의 빔 폭을 제어하였다. 이것을 시험 제작하여 이론 및 실험적으로 해석한 결과 주엽의 -3 dB 빔 폭을 7.6° ∼ 16.2°의 범위에서 제어 가능함을 확인하였다.

• 대한기계학회논문집A
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• 제30권3호
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• pp.342-348
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• 2006

A new magnetostrictive patch array transducer for the generation and detection of torsional waves is developed fur the on-line health monitoring of rotating shafts. Even though the torsional wave is useful in nondestructive evaluation due to its non-dispersive property, a transducer generating torsional waves in rotating shafts has not been developed so far. In this research, a torsional wave transducer using the magnetostrictive effect is newly developed. By bonding an away of magnetostrictive rectangular patches on the outer surface of the shaft at an oblique angle of $45^{\circ}$ and encircling the array by a solenoid coil, we have successfully generated and measured torsional waves by the developed transducer. Several experiments were carried out to check the transducer performance.

• 비파괴검사학회지
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• 제35권2호
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• pp.120-127
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• 2015

본 논문에서는 기존의 비파괴 초음파검사 시 사용되는 단일소자 탐촉자와 부채꼴 위상배열 탐촉자의 단점을 보완할 수 있는 선형배열 탐촉자를 설계 및 제작하였다. 선형배열 탐촉자는 KLM 해석 기반의 PiezoCAD 프로그램과 FEM 해석 기반의 PZFlex 프로그램을 사용하여 설계되었으며 고해상도를 위한 광대역 특성을 갖도록 압전소자 설계 시 2-2 복합체 구조를 도입하였다. 설계된 적층 구조를 바탕으로 128개 소자를 갖는 선형배열 탐촉자를 제작하고 시뮬레이션 결과와 성능 비교를 수행하였다. 제작된 선형배열 탐촉자는 5.5 MHz의 중심주파수를 가지며 -6 dB 에서 70%의 주파수 대역폭을 나타내어 초음파검사 시 검사체 내부의 효과적인 영상을 제공할 수 있을 것으로 기대한다.