• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.16-16
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• 2017

국내 농업인구 감소 대비 식품소비량이 증가함에 따라 농가의 인력을 대체하고 다양한 작업이 가능하며 가격이 저렴한 국내 기계화 기술이 필요하다. 무동력 디스크해로우 작업기는 경운과 배토가 가능한 복합작업기로서 작업기를 구성하는 주요 구성품들은 필드작업에 의해 발생되는 하중에 구조적 강도와 신뢰성이 충분히 확보되어야 한다. 또한, 실제로 필드 작업 시 작업기에 걸리는 하중은 복합하중 형태로 전달되기 때문에 단순한 형태 하중에 비해 하중계측에 어려운 점이 있으므로 하중계측점의 선정이 매우 중요하다. 본 논문에서는 하중계측점을 선정하기 위하여 복합기의 주요 구성품인 치즐(chisel) 및 디스크해로우암(disk harrow arm)에 대하여 구조해석을 수행하였으며, 3축 방향의 단위하중 응력 계산결과로부터 load reconstruction을 위한 스트레인 게이지 위치를 선정하였다. 또한, 스트레인 게이지의 신호가 하중해석에 적절한 값이 되도록 기존의 형상을 수정하였다.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.220.2-220.2
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• 2005

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.297-298
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• 2010

선박 추진축계의 동력을 계측하기 위해서는 일반적으로 스트레인 게이지를 이용한 방법이 널리 사용된다. 이러한 방법의 경우 스트레인 게이지 외에도 많은 부품들을 축에 장착해야 하며 전원을 공급하기 위해 별도의 장치를 필요로 하는 등 설치 시 매우 복잡하고 섬세한 작업이 요구된다, 뿐만 아니라 계측신호를 취득하고 분석하기 위해서도 고도의 전문성이 요구되기 때문에 운전 중의 실시간 계측을 통한 모니터링 목적이 아니라 시험 및 검증을 위해 사용될 뿐이다. 따라서 본 연구에서는 이와 같은 단점들을 보완하면서도 추진축계의 동력을 비교적 용이하게 계측하기 위한 새로운 방법을 제안하고자 한다. 본 연구에서 제안하는 계측기법은 카메라를 사용하여 축동력을 계측하는 방법으로 실험결과를 통해 유효성을 확인하였으며 항해 중 실시간 모니터링이 가능한 감시 시스템을 구축할 수 있는 새로운 계측기술이라 할 수 있다.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.25-32
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• 2007

Because of the increasing use of clayey soil as the backfill in reinfurced soil structures and embankments, nonwoven geotextiles of drain capability have been receiving much attention. However, there are few studies on the deformation behavior analysis of nonwoven geotextiles in reinforced soil structures in the site because nonwoven geotextiles which have low tensile stiffness and higher deformability than geogrids and woven geotextiles, are difficult to measure their deformation by using strain gauges. In this study, it was suggested that a new and more convenient method could measure the deformation behaviour of nonwoven geotextile using a strain gauge and examine the availability of the method by conducting laboratory tests and applying to two geosynthetics reinforced soil (GRS) walls in the site. The result of wide-width tensile test conducted under confining pressure of 70 kPa shows that the local deformation of nonwoven geotextile to be measured with strain gauges has a similar pattern to the total deformation measured with LVDT. In the GRS walls, nonwoven geotextile shows a larger deformation range than the woven geotextile and geogrid. However, the deformation patterns of these three reinforcement materials are similar. The function of strain gauges attached to nonwoven geotextile in the walls works normally for 16 months. Therefore, the method proposed in this study for measuring nonwoven geotextile deformation using a strain gauge has proved useful.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.529-535
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• 2016

This study focuses on the comparison of measured data from 6-DOF motion sensor and strain gauge installed in the IBRV ARAON during 2015 summer voyage in the Arctic. Procedures to calculate the global ice load from MotionPak II inertial measurement system and the local load from stain gauge system are discussed. The ship's speed and peak load are determined in the concept of an ice collision "event". It is found that the peak values in the global ice calculated form whole ship motion analysis fall in the range of 1.5~3 times of the local ice load based in strain gauge measurement.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.288-294
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• 2016

In modern ships, the shafting system often becomes stiff owing to the high engine power, whereas the hull structure becomes more flexible owing to optimization using high-tensile-strength thick steel plates; therefore, more sophisticated shaft alignments are required. In this study, strain gauge-based measurement was conducted under five vessel operating conditions and bearing reaction forces and hull deflections affecting shaft alignment were analyzed for a 50,000 dead weight tonnage oil/chemical tanker that has gained repute as an eco-friendly vessel in recent years. Furthermore, the analytical results from each technique-theoretical calculation, jacking ups, and strain gauges-were cross-checked against each other in order to enhance the degree of accuracy and reliability of the calculation.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.217-224
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• 2008

Trusses are found in many common structures such as bridges and buildings. The truss is a fundamental design element in engineering structures and it is important for an engineer to apply the truss design to engineering structures by understanding the mechanics of truss element. In an experimental course, the experiment selves as an example of the usefulness of the Wheatstone bridge in amplifying the output of a transducer. With the apparatus described here, it is possible to obtain experimental measurements of forces in a truss member which agree within errors to predictions from elementary mechanics. The apparatus is inexpensive, easy to operate, and suitable as either a classroom demonstration or student laboratory experiment. This device is a small table-top experiment. The conventional strain measuring device is costly and complicated - it is not simple to understand its structure. Hence, strain gage and the A/D converter are assembled to come up with a load and a strain measuring device. The device was tested for measuring the strain in a loaded specimen and the results were compared to those predicted by theory of mechanics.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.178-184
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• 2012

In this study, implementation process of sensor-embedded main wing model for structural health monitoring is described. Fiber Bragg Grating (FBG) Sensor, Plumbum-Zirconate-Titanate (PZT) Sensor, and strain gauge are installed in the main wing of Jabiru UL airplane as a test-bed of Health and Usage Monitoring System (HUMS).

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1152-1161
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• 2009

The power measurement of main propulsion system on the new vessels can be classified with the direct method acquired from the shaft's strain using strain gauge and the indirect method converted and summed from all of cylinders combustion pressure using mechanical or electrical pickup device during the sea trial. This power is fluctuated by external factors which was influenced by various sea motions with long time interval and by internal factors which was influenced by varying torques of torsional vibration and bending moment, due to mis-aligned shaft and whirling vibration with short time interval. In this paper, the statistical analysis method for the shaft power measurement and assessment using strain gauge in marine vessels are introduced. And these are identified by the low speed two stroke diesel engine model and four stroke medium speed diesel engine model including reduction gear.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.301-306
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• 2016

During the initial stage of propulsion shaft design, the shaft alignment process includes a thorough consideration of lateral vibration to verify the operational safety of the shaft. However, a theoretical method for analyzing forced lateral vibrations has not been clearly established. The methods currently used in classification societies and international standards can only ensure a sufficient margin to avoid the blade-passing frequency resonance speed outside the range of ${\pm}20%$ of the maximum continuous rating (MCR) for the engine. Typically, in shaft alignment analyses, longer center distances between the support bearings promote affirmative results, but the blade order resonance speed can approach the lower limit for lateral vibration. Therefore, this matter requires careful attention by engineers, and a verification of the theoretical analysis by experimental measurements is highly desirable. In this study, both theoretical and experimental analyses were conducted using strain gauges under two draught conditions of vessels used as 50,000-DWT oil/chemical tankers, introduced recently as eco-friendly ships. Based on the analyses, the influence of the lateral vibration on the shafting system and the system's reliability was reviewed.