• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 춘계학술대회
• /
• pp.248-250
• /
• 2009

육질의 특성을 파악하기 위해 광학적인 방식의 비파괴적인 측정 방법을 사용하여 실험을 수행하였다. 육질의 특성은 분광 분석법을 사용하여 측정하였다. 이를 통해 육질의 근육 및 지방의 분포에 따른 특성의 파악이 가능할 것으로 예상된다.

• 비파괴검사학회지
• /
• 제30권6호
• /
• pp.558-563
• /
• 2010

In this paper, the novel approach for the fault diagnosis of the bearing equipped with rotational mechanical facilities was studied. As research works, by applying the ball bearing used extensively in many industrial fields, experiments were conducted in order to propose the new prognostic method about the condition monitoring for the rotational bodies based on the condition analysis of infrared thermography. Also, by using the vibration spectrum analysis, the real time monitoring was performed. As results, it was confirmed that infrared thermography method could be adapted into monitor and diagnose the fault for bearing by evaluating quantitatively and qualitatively the temperature characteristics according to the condition of the ball bearing.

• 한국정밀공학회지
• /
• 제15권11호
• /
• pp.121-129
• /
• 1998

In-plane ESPI(Electronic Speckle Pattern Interferometry) was devised to measure in-plane deformations and rotation of a specimen with laser in this study. ESPI is a optical measuring method to be able to measure the deformations of engineering components and materials in industrial fields. The conventional measuring methods of surface deformations such as the strain gauge have many demerits because they are contact and point-to-point measuring ones. But that ESPI is noncontact, nondestructive and whole field measuring method can overcome previous disadvantages. We used ESPI which is sensitive to in-plane displacement for measuring in-plane deformations of a disk. And the 4-frame phase shifting method was used for the quantitative analysis. First of all, the system calibration was done due to an in-plane rotation before getting deformations of a disk. Finally we showed good agreement between the experiment results and those of the FEA(Finite Element Analysis).

• 비파괴검사학회지
• /
• 제22권6호
• /
• pp.643-648
• /
• 2002

In this study, shearography and ESPI have been used for quantitative analysis of an inside crack of pipeline and both of them appeared suitable to qualitatively detect inside crack. However, shearography needs several effective factors including the amount of shearing, shearing direction and induced load for the quantitative evaluation of the inside crack. In this study, the factors were optimized for the quantitative analysis and the site of cracks has been determined. Although the effective factors in shearography has been optimized, it is difficult to determine the factors exactly because they are related to the details of tracks. On the other hand, ESPI is independent on the details of a crack and only the induced load plays an important role. The out-of-plane displacement was measured under the optimized load and the measured were numerically differentiated, which resulted in an equivalent to the shearogram. The size of cracks can be determined quantitatively without any detail of a crack.

• 비파괴검사학회지
• /
• 제23권3호
• /
• pp.189-197
• /
• 2003

Nucleation of a crack is readily defected by acoustic emission (AE) method. One powerful technique for AE waveform analysis has been developed as SiGMh (Simplified Greens functions for Moment tensor Analysis), as crack kinematics of locations, types and orientations are quantitatively determined. Because these kinematical outcomes are obtained as three-dimensional (3-D) locations and vectors, 3-D visualization is definitely desirable. To this end, the visualization system has been developed by using VRML (Virtual Reality Modeling Language). As an application, failure protest of a reinforced concrete beam is discussed.

• 대한기계학회논문집A
• /
• 제23권11호
• /
• pp.1878-1885
• /
• 1999

Ultrasonic technique which is one of the most common nondestructive evaluation techniques has been applied to evaluate the integrity of structures by analyzing the characteristic of scattering sign al from internal defects. Therefore, a numerical analysis of ultrasonic scattering field due to defect profiles is absolutely needed for the accurate, quantitative estimation of internal defects. In this paper, the SH-wave scattering by multi-cavity defects and inclusion using Elastodynamic Boundary Element Method is studied. The effects of shape and distance of defects on transmitted and reflected fields are considered. The interaction of multi-cavity defects in SH-wave scattering is also investigated. Numerical calculations by the BEM have been carried out to predict near field solution of scattered fields of ultrasonic SH-wave. The presented results can be used to improve the detection sensitivity and pursue quantitative nondestructive evaluation for inverse problem.

• Journal of Biosystems Engineering
• /
• 제37권5호
• /
• pp.319-326
• /
• 2012

Purpose: Cheese texture is an important sensory attribute mainly considered for consumers' acceptance. The feasibility of nondestructive measurements of cheese texture was explored using non-contact ultrasonic sensors. Methods: A novel non-contact air instability compensation ultrasonic technique was used for five varieties of hard cheeses to measure ultrasonic parameters, such as velocity and attenuation coefficient. Five texture properties, such as fracturability, hardness, springiness, cohesiveness, and chewiness were assessed by a texture profile analysis (TPA) and correlated with the ultrasonic parameters. Results: Texture properties of five varieties of hard cheese were estimated using ultrasonic parameters with regression analysis models. The most effective model predicted the fracturability, hardness, springiness, and chewiness, with the determination coefficients of 0.946 (RMSE = 21.82 N), 0.944 (RMSE = 63.46 N), 0.797 (RMSE = 0.06 ratio), and 0.833 (RMSE = 17.49 N), respectively. Conclusions: This study demonstrated that the non-contact air instability compensation ultrasonic sensing technique can be an effective tool for rapid and non-destructive determination of cheese texture.

• 비파괴검사학회지
• /
• 제35권4호
• /
• pp.258-267
• /
• 2015

Eddy current testing is widely used for inspecting steam generator tubing in nuclear power plants (NPPs). The inspection technique for steam generator tubing in NPPs should be qualified in accordance with examination guidelines. When the components of a qualified system such as eddy current tester, probe, and data analysis program, are changed, the equivalency of the modified system to the originally qualified system must be verified. The eddy current tester is the most important part of an eddy current testing system because it excites and transmits alternating currents to the probe, receives coil impedance of the probe and generates signals for anomalies. The Korea Hydro & Nuclear Power Co., Ltd. (KHNP) developed an eddy current testing system with an eddy current tester and data acquisition-analysis program for inspecting the steam generator tubing in NPPs; this system can be used for an array probe and as a bobbin and rotating probes. The equivalency assessment for the currently developed system was carried out, and we describe the results in this paper.

• 헤리티지:역사와 과학
• /
• 제34권
• /
• pp.4-18
• /
• 2001

Paekche black potteries are earthenwares begun to be produced at the beginning of Paekche Dynasty, around 3-century. They have typical Paekche style. Representative Paekche earthenwares are burnished black pottery, long oval shaped pots and shoulder pots. Among these, burnished black potteries are limited to Paekche in the occurrence site and age. Their numbers are a few. To reproduce black pottery, their compositions were analyzed. As a result of X-Ray analysis, quarts, feldspar, illite, muscovite, and anorthite were found on their surfaces and imsides spinel and vermiculite were found on their surfaces. Since same constituent minerals were found on surfaces and their insides, special other materials were not added to make surface black. With the showing vermiculite, they were made higher than $800^{\circ}C$. As a result of analysis, fine grained clay bad been influenced by the black smoke. Its luster was appeared by polishing with a big flat wooden spoon. The black color was made of smoking when the hot pot taken off from burning oven was covered with the wet pine leaves.

• Wind and Structures
• /
• 제34권6호
• /
• pp.525-538
• /
• 2022

High-rise wooden pagodas generate large displacement responses under wind action. It is necessary and wise to reduce the wind loads and wind-induced responses on the architectural heritage using artificial plants, which do not damage ancient architecture and increase greenery. This study calculates and analyzes the wind loads and wind-induced responses on the Yingxian Wooden Pagoda, in China, using artificial plants via the finite element analysis (FEA). A three-dimensional wind-loading field was simulated using a wind tunnel test. Wind loads and wind-induced responses, including the displacement and acceleration of the pagoda with and without artificial plants, were analyzed. In addition, three types of tree arrangements were discussed and analyzed using the score method. The results revealed that artificial plants can effectively control wind loads and wind-induced displacements, but the wind-induced accelerations are enlarged to some extent during the process. The height of the tree significantly affected the shelter effects of the structure. The distance of trees from the pagoda and arrangement width of the tree had less influence on shelter effects. This study extends the understanding of the nondestructive method based on artificial plants, for controlling the wind base loads and structural responses of wooden pagodas and preserving architectural heritage via FEA.