High-speed angular-scan pulse-echo ultrasonic propagation imager for in situ non-destructive evaluation

Syed H. Abbas,Jung-Ryul Lee 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.2

This study examines a non-contact laser scanning-based ultrasound system, called an angular scan pulse-echo ultrasonic propagation imager (A-PE-UPI), that uses coincided laser beams for ultrasonic sensing and generation. A laser Doppler vibrometer is used for sensing, while a diode pumped solid state (DPSS) Q-switched laser is used for generation of thermoelastic waves. A high-speed raster scanning of up to 10-kHz is achieved using a galvano-motorized mirror scanner that allows for coincided sensing and for the generation beam to perform two-dimensional scanning without causing any harm to the surface under inspection. This process allows for the visualization of longitudinal wave propagation through-the-thickness. A pulse-echo ultrasonic wave propagation imaging algorithm (PE-UWPI) is used for on-the-fly damage visualization of the structure. The presented system is very effective for high-speed, localized, non-contact, and non-destructive inspection of aerospace structures. The system is tested on an aluminum honeycomb sandwich with disbonds and a carbon fiber-reinforced plastic (CFRP) honeycomb sandwich with a layer overlap. Inspection is performed at a 10-kHz scanning speed that takes 16 seconds to scan a 100 ⨯ 100 mm2 area with a scan interval of 0.25 mm. Finally, a comparison is presented between angular-scanning and a linear-scanning-based pulse-echo UPI system. The results show that the proposed system can successfully visualize defects in the inspected specimens. This study examines a non-contact laser scanning-based ultrasound system, called an angular scan pulse-echo ultrasonic propagation imager (A-PE-UPI), that uses coincided laser beams for ultrasonic sensing and generation. A laser Doppler vibrometer is used for sensing, while a diode pumped solid state (DPSS) Q-switched laser is used for generation of thermoelastic waves. A high-speed raster scanning of up to 10-kHz is achieved using a galvano-motorized mirror scanner that allows for coincided sensing and for the generation beam to perform two-dimensional scanning without causing any harm to the surface under inspection. This process allows for the visualization of longitudinal wave propagation through-the-thickness. A pulse-echo ultrasonic wave propagation imaging algorithm (PE-UWPI) is used for on-the-fly damage visualization of the structure. The presented system is very effective for high-speed, localized, non-contact, and non-destructive inspection of aerospace structures. The system is tested on an aluminum honeycomb sandwich with disbonds and a carbon fiber-reinforced plastic (CFRP) honeycomb sandwich with a layer overlap. Inspection is performed at a 10-kHz scanning speed that takes 16 seconds to scan a 100 ⨯ 100 mm2 area with a scan interval of 0.25 mm. Finally, a comparison is presented between angular-scanning and a linear-scanning-based pulse-echo UPI system. The results show that the proposed system cThis study examines a non-contact laser scanning-based ultrasound system, called an angular scan pulse-echo ultrasonic propagation imager (A-PE-UPI), that uses coincided laser beams for ultrasonic sensing and generation. A laser Doppler vibrometer is used for sensing, while a diode pumped solid state (DPSS) Q-switched laser is used for generation of thermoelastic waves. A high-speed raster scanning of up to 10-kHz is achieved using a galvano-motorized mirror scanner that allows for coincided sensing and for the generation beam to perform two-dimensional scanning without causing any harm to the surface under inspection. This process allows for the visualization of longitudinal wave propagation through-the-thickness. A pulse-echo ultrasonic wave propagation imaging algorithm (PE-UWPI) is used for on-the-fly damage visualization of the structure. The presented system is very effective for high-speed, localized, non-contact, and non-destructive inspection of aerospace structures. The system is tested on an aluminum honeycomb sandwich with disbonds and a carbon fiber-reinforced plastic (CFRP) honeycomb sandwich with a layer overlap. Inspection is performed at a 10-kHz scanning speed that takes 16 seconds to scan a 100 ⨯ 100 mm2 area with a scan interval of 0.25 mm. Finally, a comparison is presented between angular-scanning and a linear-scanning-based pulse-echo UPI system. The results show that the proposed system can successfully visualize defects in the inspected specimens.an successfully visualize defects in the inspected specimens.

Development of Technology for Determining Rice Amylose Content using Near-infrared Spectroscopy

( Miki Matsuo ),( Shuso Kawamura ),( Mizuki Kato ),( Edenio Olivares Diaz ),( Shigenobu Koseki ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Rice is staple food for people in the large part of the world, especially in Asian countries. The major chemical constituent contents of rice are moisture, protein and starch (amylose and amylopectin). Those chemical constituents associate with eating quality of rice. Near-infrared (NIR) spectroscopy is one of the non-destructive methods for determining grain chemical contents. Moisture and protein contents can be measured with high accuracy using NIR spectrometer at rice grain elevator in Japan. However, the accuracy to measure amylose content is not sufficient. Thus, there is a strong need for the highly accurate measurement of rice amylose content using non-destructive method. The overall objective of this study was to develop non-destructive techniques to determine rice amylose content for practical use at rice grain elevator. Amylose content measurement was performed using an auto-analyzer for reference (chemical) analysis. Spectra data of rice were obtained using an NIR spectrometer with a wavelength range of 850 to 1048 nm. Calibration model to determine amylose content was developed using non-waxy Japonica-type rice samples (calibration set, n=974, including 14 cultivars) grown in Japan from 2008 to 2016. Partial least squares (PLS) regression analysis was used to develop calibration model. The accuracy of the model was validated using other rice samples (validation set, n=95, including 10 cultivars) grown in 2017. There are two cultivar groups of non-waxy Japonica-type rice produced in Japan. One is ordinary amylose content rice cultivar and the other is low amylose content rice cultivar. The accuracy of determination of rice amylose content was improved by increasing production years of calibration sample set. When one calibration model to determine amylose content was developed using all cultivars together, validation statistics were shown: coefficient of determination (r²) was 0.72, bias was -0.04%, standard error of prediction (SEP) was 0.92%, and ratio of SEP to standard deviation of reference data (RPD) was 1.90. To improve the accuracy of determination of rice amylose content, two calibration models were developed using ordinary amylose content rice cultivars or low amylose content rice cultivars, respectively. As a result, the accuracy of two calibration models was better than that of one calibration model. Validation statistics of the two calibration models were shown: coefficient of determination (r²) was 0.93, bias was 0.01%, standard error of prediction (SEP) was 0.64%, and ratio SEP to standard deviation of reference data (RPD) was 2.76. The production year of validation set (2017) was different from those of calibration set (2008 to 2016). This is the same condition as practical use of this non-destructive method at rice grain elevator. The result obtained in this study indicated that the two calibration models enables non-destructive determination of rice amylose content at rice grain elevator.

유도탄 신뢰성평가 분야 중성자 비파괴검사 기법 적용 연구

박경환(Gyeong Hwan Park),김종열(Jongyul Kim),문명국(Myung Kook Moon),이남례(Namrye Lee) 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.9

유도탄은 장기간 저장되는 고가의 무기체계로서 1번의 사용으로 임무를 다하는 특성을 가지며, 주로 20년이상 군에서 운용되기 때문에 유도탄에 대한 사용가능성, 신뢰성, 안전성 등을 평가하고 관리하는 것은 매우 중요한 업무이다. 유도탄의 수명을 좌우하는 주요 부품들은 1회 사용 시 재사용이 불가능한 One-Shot Device이며, 이러한 부품들의 신뢰성평가 방법에는 비파괴 검사가 주로 활용된다. 비파괴검사란 무기체계에 영향을 주지 않고 검사하는 방법으로서, 재료에 파괴나 손상을 주지 않기 때문에 고가의 무기체계 검사에 주로 활용된다. 비파괴검사에는 방사선, 누설, 초음파등 다양한 검사방법이 존재하며, 유도탄 비파괴검사에는 주로 X-선 이용한 방사선 투과검사가 활용된다. 그러나 X-선의 경우 원자번호가 높은 물질로 구성된 부품에 대한 투과력이 낮아, 내부결함 검사에 제한이 있는 경우가 자주 발생한다. 이러한 X-선검사의 단점을 보완할 수 있는 비파괴검사 방법이 바로 중성자 투과검사이다. 중성자 투과검사는 X-선과 달리 원자번호가 높은 물질에 대한 투과력이 강한 반면, 물과 같이 가벼운 물질에 대한 투과성은 낮은 특성을 가진다. 본 연구에서는 유도탄 신뢰성평가 분야에 중성자 비파괴검사 기술을 적용하기 위한 연구들을 수행하였으며, 기존 X-선 검사 결과를 비교분석하여 향후 중성자와 X-선을 융합한 디지털 트윈기술의 활용 필요성을 검토하였다. A guided missile is an expensive weapon system stored for an extended period that can fulfill its mission with a single use. Evaluating and managing the usability, reliability, and safety of guided missiles is vital because the military has operated them for more than 20 years. The main parts that determine the lifespan of a guided missile are One-shot Devices that cannot be reused. Non-destructive testing is a method of inspecting a weapon system without destruction or damage. Accordingly, non-destructive testing is used mainly to evaluate the reliability of expensive weapon system inspections. Various types of non-destructive inspection methods are available, such as radiographic inspection, leak inspection, and ultrasonic inspection, and radiographic inspection using X-rays is used mainly for the non-destructive inspection of guided missiles. On the other hand, in the case of radiographic inspection using X-rays, internal defect inspection is often limited to parts composed of materials with high atomic numbers. The neutron transmission inspection method is a non-destructive inspection method that can compensate for the disadvantages of X-ray inspection. Unlike x-rays, neutrons have high penetrating power for materials with high atomic numbers and low penetrating power for materials with low atomic numbers, such as water. In this study, studies were conducted to apply neutron non-destructive testing technology to a missile reliability evaluation, and a comparative analysis was performed with the existing X-ray test results.

타격음율 이용한 복합재료 구조물의 비파괴 검사법 개발

황준석 ( Hwang Jun Seog ),김승조 ( Kim Seung Jo ) 한국복합재료학회 2004 Composites research Vol.17 No.1

본 연구에서는 타격음을 이용한 비파괴 검사법을 제안하였다. 제안된 방법(tapping sound analysis)은 건강한 구조물과 손상된 구조물의 타격음의 차이를 분석하여 구조물의 손상 유무를 판단하는 방법이다. 타격음의 직접적인 비교는 비효율적이므로 타격음으로부터 특성을 추출하기 위해 wavelet packet transform에 기반한 특성추출법을 제안하였다. 또한 추출된 특성 자료를 바탕으로 손상의 유무를 판단하는 지표로서 특성 지수를 정의하였다. 제안된 방법의 타당성을 밝히기 위해 실험적인 검증을 수행하였다. 복합재료를 이용하여 건강한 구조물과 손상된 구조물을 제작하고 타격음을 측정하였다. 제안된 손상 판단 기법을 이용한 결과로부터 특성 지수에 의한 손상 판단의 타당성을 밝혔다. A new non-destructive evaluation method using tapping sound is proposed. This method, named Tapping Sound Analysis, is using the difference between tapping sound data of healthy structure and defective structure as the criteria of determination of internal defect of composite structure. For the characterization of tapping sound, a feature extraction method based on wavelet packet transform is proposed. And a feature index is defined for the decision of existence of internal defects. To prove the possibility of proposed method as a non-destructive evaluation method, experimental study is performed. The tapping sound data of healthy structure and defective structure are measured and compared based on the proposed decision method. The experimental results showed that the feature index is a good indicator for the determination of internal defects.

In situ non-destructive evaluation of an aircraft UHF antenna radome based on pulse-echo ultrasonic propagation imaging

Shin, Hye-Jin,Park, Jae-Yoon,Hong, Seung-Chan,Lee, Jung-Ryul Elsevier 2017 Composite structures Vol.160 No.-

<P><B>Abstract</B></P> <P>Most aircraft antennas are protected by radomes made of composite materials. However, antenna radome structures are easily damaged by external forces and internal manufacturing defects. To detect damage in the composite antenna radomes while in service, a full-field pulse-echo ultrasonic propagation imaging (PE UPI) system is proposed as an in situ non-destructive inspection technique, which is mobile inside a hangar. The radome is generally a double-curvature structure, and thus, a curvature compensation algorithm is also developed to increase damage visibility. The proposed hardware and software have been tested by detecting a resin rich region formed between the E-glass/epoxy plies. To visualize the damage, PE ultrasonic wave propagation imaging has been performed, and ultrasonic energy mapping has also been applied. A curvature compensating algorithm has been newly developed and compared for its performance in damage visibility improvement. To verify the size of the real defects of a UHF antenna radome, destructive testing has been performed by cutting the defect area, polishing the cross section and investigating the section using a 50× microscope. The results have shown the feasibility of the proposed PE UPI system and the inspection strategy as an in situ non-destructive evaluation technique for radome structures.</P>

복합재 격자 구조 비파괴평가를 위한 초음파전파 영상화 시스템 활용 연구

박재윤,신혜진,이정율 한국복합재료학회 2017 Composites research Vol.30 No.6

Composite lattice structures are tried to be used in various fields because of its benefit in physical properties. With increase of demand of the composite lattice structure, nondestructive testing technology is also required to certificate the quality of the manufactured structures. Recently, research on the development of the composite lattice structure in Republic of Korea was started and accordingly, fast and accurate non-destructive evaluation technology was needed to finalize the manufacturing process. This paper studied non-destructive testing methods for composite lattice structure using laser ultrasonic propagation imaging systems. Pulse-echo ultrasonic propagation imaging system was able to inspect a rib structure wrapped with a skin structure. To reduce the time of inspection, a band divider, which can get signal in different frequency bands at once, was developed. Its performance was proved in an aluminum sandwich panel. In addition, to increase a quality of results, curvature compensating algorithm was developed. On the other hand, guided wave ultrasonic propagation imaging system was applied to inspect delamination in a rib structure. To increase an area of inspection, multi-source ultrasonic wave propagation image was applied, and defects were successfully highlighted with variable time window amplitude mapping algorithm. These imply that ultrasonic propagation imaging systems provides fast and accurate non-destructive testing results for composite lattice structure in a stage of the manufacturing process. 복합재 격자 구조는 동일한 무게를 갖는 다른 구조에 비해 더 큰 하중을 견딜 수 있다는 장점으로 인해 다양한 분야에 적용이 시도되고 있다. 최근, 국내에서도 복합재 격자 구조 제작을 위한 기술 개발이 이루어지고 있으며 이에 복합재 격자 구조를 빠르고 정밀하게 검사할 수 있는 비파괴검사 기술의 개발 역시 필요하게 되었다. 본 논문에서는 초음파전파 영상화 시스템들을 활용하여 복합재 격자 구조에 빠르고 정밀한 비파괴검사를 하기 위한 연구를 수행하였다. 레이저 펄스에코 초음파전파 영상화 시스템을 통해 스킨에 쌓여 있는 복합재 격자 구조의내부 리브 구조를 관찰할 수 있었고 접착분리를 검출할 수 있는 가능성을 확인하였다. 또한 검사시간을 줄이기 위해 주파수 영역을 최적화 하기 위한 밴드 디바이더를 개발 적용하였으며, 검사 결과의 질을 향상시키기 위해 곡률 보상 알고리즘을 개발하였다. 유도파 초음파전파 영상화 시스템으로는 리브 구조에 있는 층간분리 결함을 확인할 수 있었으며, 다중 소스 초음파전파영상을 통해 검사 영역을 확대시켰고 가변시간창 진폭 이미지 알고리즘을 통해 결함을 강조시킬 수 있도록 했다. 이와 같은 결과들을 통해 격자구조에 최적화 된 초음파전파 영상화 시스템의 지속적인 개발이 이뤄지면 복합재 격자 구조의 대량생산에 이은 고속 정밀 비파괴검사가 이뤄질 수 있을것으로 판단된다.

PLC제어와 영상처리를 이용한 계란의 비파괴 신선도 측정 시스템 개발

김태정,김선정,이동구,이정호,이영석,황헌,최선 한국정보전자통신기술학회 2019 한국정보전자통신기술학회논문지 Vol.12 No.2

Non-destructive freshness measurement using spectroscopy has been carried out several times, but research on freshness and freshness has not been conducted. Therefore the purpose of this study is to develop a system for visually measuring and quantifying the air sack inside the egg by non - destructive method. The experimental environment which designed a small chamber was composed of 850nm band of two IR lasers, IR camera and two servo motors to acquire air sack Images. When the air sack volume ratio is 2.9% or less and the density is 0.9800 or more, the Haugh Unit value is 60 or more It was judged to be a fresh egg of a grade B or higher. These results mean, using the weight measurement, nondestructive decision system, and freshness evaluating algorithm. It can be expected to distinguish grade B or more marketable eggs without using destructive methods. 분광법을 이용한 비파괴 신선도 측정 연구들이 여러 차례 진행되어 왔지만, 기실과 신선도 간의 연구가 진행되지 않았다. 따라서 본 연구에서는 비파괴 방식으로 계란 내부의 기실을 시각적으로 계측하며 정량화하는 시스템을 개발함에 목적이 있다. 소형 챔버로 구성된 실험 환경은 2개의 850nm 대역의 IR 레이저, 2개의 서보모터, IR Cut RGB 카메라로 구성되며 계란 기실의 영상을 획득한다. 본 논문에서 계란의 기실 부피 비율이 2.9% 이하이고 밀도가 0.9800() 이상이면 60 이상의 호우 유닛 값을 갖는 B등급 이상의 신선한 계란으로 판단한다. 상기 결과 중량측정용 저울, 비파괴 판정시스템과 신선도 측정 알고리즘이 있으면 계란을 파괴하지 않고 B등급 이상의 판매 가능한 계란을 판정할 수 있음을 의미한다. 향후 계란의 신선도 판정을 할 때 계란의 기실 부피 비율과 밀도를 이용하여 계란 신선도를 비파괴 적으로 판별할 수 있는 기초 자료로 사용할 수 있기를 기대한다.

포토믹서 테라헤르츠 기술 기반의 영상화 시스템을 통한 유리섬유 복합재료 결함의 비파괴검사법

오경환,김덕중,박동운,지영빈,오승재,김학성 한국비파괴검사학회 2018 한국비파괴검사학회지 Vol.38 No.1

In this study, non-destructive evaluation using photo-mixer terahertz technique was studied to visualize the hidden damage in composite structures. A terahertz wave system was developed based on photo-mixer to detect the internal defects of the composite structure, and foreign material was simulated in a glass fiber-reinforced plastic (GFRP) specimen using PET film coated with silver nano-wire. For the visualization, an imaging algorithm for terahertz signal processing and stage control was developed using a GUI based on LABVIEW. The inspection was performed using the developed continuous terahertz inspection system and the terahertz waveform acquired in the single frequency was used to visualize defects. 본 논문에서는 포토믹서 테라헤르츠 기술 기반의 영상화 시스템을 이용하여 유리섬유 복합재료의 결함을 영상화하기 위한 비파괴검사 기술에 대한 연구를 진행하였다. 유리섬유 복합재료 구조물의 내부 결함을 검사하기 위해 photomixer 기반의 테라헤르츠 발생 시스템을 이용하였고, 복합재 제작 공정 중에 시편 내부로 들어갈 수 있는 이물질을 모사하기 위해 유리섬유복합재료(GFRP) 시편 내부에 은 나노와이어가 입혀진 PET 필름을 사용하여 모사하였다. 내부 결함의 영상화를 위해 테라헤르츠 신호의 처리와 stage 제어를 위한 영상화 알고리즘을 Labview 기반의 GUI를 통해 개발하였다. 제작된 포토믹서 테라헤르츠 검사 시스템을 사용하여 결함 검사를 수행하였고, 단일 주파수를 이용해 취득한 테라헤르츠 파형을 영상화 하였다.

근적외선 비파괴 과일 선별 시스템을 활용한 내부 갈변 사과의 판별

김밝금(Bal Geum Kim),임종국(Jong Guk Lim) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.1

본 논문에서는 농산물 산지 유통 센터에서 설치되어 사용하고 있는 비파괴 과일 선별 시스템을 이용하여 정상사과와 내부에 결함이 있는 사과를 판별하기 위한 최적 파장과 해당 스펙트럼의 특성을 구명하고자 하였다. 총 54개 사과에 대해 470 - 1150 nm의 파장 범위에서 정상 사과와 갈변 사과의 투과 스펙트럼을 획득하였다. 주성분 분석(PCA)을 활용하여 정상 사과와 내부 갈변 사과의 군집을 확인하였으며, 판별 모델의 개발과 평가를 위해 부분최소제곱회귀(PLSR) 분석을 수행하였다. PCA 분석에서는 정상 사과와 내부 갈변 사과 군집의 확연한 구분이 보여 높은 판별율의 결과를 보여주었다. PLSR 분석 결과, 전처리를 하지 않은 예측 모델의 상관계수(R)는 0.902, RMSE 값은 0.157이었으며, 전처리를 적용했을 때 예측 모델의 상관계수는 0.906, RMSE 값은 0.154이었다. 따라서, 이 PLSR 모델은 이 시스템을 활용해 내부 갈변이 있는 사과도 우수하게 판별할 수 있음을 알 수 있었다. 이와 같은 방식을 이용할 경우, 외부 결함과 더불어 내부 결함에 대한 농산물 선별과 평가에 적용될 수 있을 것으로 사료된다. There is a lack of studies comparing the internal quality of fruit with its external quality. However, issues of internal quality of fruit such as internal browning are important. We propose a method of classifying normal apples and internally browned apples using a near-infrared (NIR) non-destructive system. Specifically, we found the optimal wavelength and characteristics of the spectra for determining the internal browning of Fuji apples. The NIR spectra of apples were obtained in the wavelength range of 470-1150 nm. A group of normal apples and a group of internally browned apples were identified using principal component analysis (PCA), and a partial least squares regression (PLSR) analysis was performed to develop and evaluate the discriminant model. The PCA analysis revealed a clear difference between the normal and internally browned apples. From the PLSR, the correlation coefficient of the predictive model without pretreatment was determined to be 0.902 with an RMSE value of 0.157. The correlation coefficient of the predictive model with pretreatment was 0.906 with an RMSE value of 0.154. The results show that this model is suitable for classifying normal and internally browned apples and that it can be applied for the sorting and evaluation of agricultural products for internal and external defects.

Non-Destructive Evaluation for Material of Thermal Barrier Coatings

Lee, Chul-Ku,Kim, Tae-Hyung 한국공작기계학회 2005 한국생산제조학회지 Vol.14 No.1

Material degradation is a multibillion-dollar problem which affects all the industries amongst others. The last decades have seen the development of newer and more effective techniques such as Focused-ion beam(FIB), Transmission electron microscopy(TEM), Secondary-ion mass spectroscopy(SIMS), auger electron spectroscopy(AES), X-ray Photoelectron spectroscopy(XPS), Electrochemical impedance spectroscopy(EIS), Photo-stimulated luminescence spectroscopy(PSLS), etc. to study various forms of material degradation. These techniques are now used routinely to obtain information on the chemical state, depth profiling, composition, stress state, etc. to understand the degradation behavior. This paper describes the use of these techniques specifically applied to materials degradation and failure analysis.