변형률계에 의해 측정된 지오그리드 인장변형률의 신뢰성

이광우(Kwang-Wu Lee),조삼덕(Sam-Deok Cho),한중근(Jung-Geun Han),홍기권(Ki-Kwon Hong),이종영(Jong-Young Lee) 한국토목섬유학회 2009 한국토목섬유학회 학술발표회 Vol.2009 No.11

This paper describes the results of a series of the wide-width tensile tests on three types of geogrid, which are conducted to assess the reliability of the tensile strains in geogrid measured by strain gauge. The strain gauge is attached during the tensile test. The tensile strain by strain gauge is larger than real strain in the geogrid and a difference between strain gauge reading and real strain nonlinearly increase with increasing the tensile strain. However, when the tensile strain is smaller than 3%, a difference between strain gauge reading and real strain is a little.

금속 외팔보에 접착된 박막 실리콘 스트레인 게이지의 제작 및 성능 평가

김용대(Yongdae Kim),김영덕(Young Deok Kim),이철섭(Chul Sub Lee),권세진(Sejin Kwon) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.4

금속은 가공성이 우수하기 때문에 다양한 형태의 구조물이나 격막을 제작할 수 있다. 이런 금속구조물이나 격막에 민감도가 월등히 우수한 실리콘 스트레인 게이지를 적용할 경우 그 응용 범위가 다양해질 수 있다. 이에 금속구조물에 다결정 실리콘 스트레인 게이지를 접착한 형태의 센서를 제안하였다. 실리콘 기판을 이용해 박막형 다결정 실리콘 스트레인 게이지를 제작하기 위한 제작공정을 확립하였으며, 제작된 실리콘 스트레인 게이지를 금속 변형부 위에 접착하기 위한 접착공정을 확립하였다. 이후 금속 외팔보에 실리콘 스트레인 게이지를 글래스 프릿 접착하여 성능평가를 실시하였다. 성능평가 결과 게이지팩터는 34.0의 값을 가졌으며, TCR(Temperature Coefficient of Resistance)은 -328 ppm/℃의 값을 가졌다. In this paper, we propose a sensor design by using a polysilicon strain gauge bonded to a metal diaphragm. The fabrication process of the thin polysilicon strain gauges having thicknesses of 50 μm was established using conventional MEMS technologies; further, the technique of glass frit bonding of the polysilicon strain gauge to the stainless steel diaphragm was established. Performance of the polysilicon strain gauge bonded to the metal cantilever beam was evaluated. The gauge factor, temperature coefficient of resistance (TCR), nonlinearity, and hysteresis of the polysilicon strain gauge were measured. The results demonstrate that the resistance increases linearly with tensile stress, while it decreases with compressive stress. The value of the gauge factor, which represents the sensitivity of strain gauges, is 34.0; this value is about 7?15 times higher than the gauge factor of a metal-foil strain gauge. The resistance of the polysilicon strain gauge decreases linearly with an increase in the temperature, and TCR is -328 ppm/℃. Further, nonlinearity and hysteresis are 0.21 % FS and 0.17 % FS, respectively.

대 변형 감지용 스트레인게이지 개발

이영태,조승우 한국반도체디스플레이기술학회 2014 반도체디스플레이기술학회지 Vol.13 No.4

In this paper, a carbon strain gauge for large strain was developed. The carbon strain gauge was fabricated by forming PCB and antenna pattern using Cu/Ni/Au film and carbon resistor pattern using screen printing process on plastic film substrate. It was possible to develop low-cost disposable strain gauge since the carbon paste was cheap and the fabrication process was simple. The wireless communication type carbon strain gauge was fabricated by integrating signal processing circuit, antenna and power all together on the same substrate as a strain gauge. The wireless communication type carbon strain gauge has a merit of being available immediately at the spot without any particular system.

다결정 실리콘 스트레인 게이지의 저항 계수

김용대(Yongdae Kim),권세진(Sejin Kwon) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

The performance of polysilicon strain gauges before and after heat treatment along with the conventional metal annealing process and the glass-frit bonding process was evaluated to investigate effect of the glass-frit bonding process. The gauge factors of the poly-silicon strain gauges that were not heat treated were determined by multiplying the resistivity coefficient of gauge factor (RCGF) and resistivity. The RCGF, which is new coefficient derived in our research, presents the resistivity dependence of the gauge factor of the polysilicon strain gauge. The gauge factors of a poly-silicon strain gauges heat treated with aluminum annealing process and glass-frit bonding process equaled the RCGF multiplying resistivity of the gauge. This RCGF was same with that of the strain gauges that were not heat treated.

대퇴 경부 골절에서의 stress와 strain에 관한 연구

이순혁,박상원,이홍건 고려대학교 의과대학 1990 고려대 의대 잡지 Vol.27 No.1

To study change of stress on the femoral neck after internal fixation of femoral neck fractures, comparison of strain on the fernoral neck between before and after femoral neck osteotomy was performed. The author used fourteen embalmed femora, two as control group and twelve as experimental group, which was further divided into two groups by difference of fixation method, and measured strains during loading along the weight-bearing axis with Instron. In two femora of the control group, five strain-gauges were bonded on five spots around the femoral neck and strains on five spots were measured. In twelve femora of the experimental group, two strain-gauges were bonded on selected two spots, each showed the highest amount of compressive or tensile strain according to experimental results of the control group among five spots, and strains were measured during loading. Then twelve femora in the experimental group, once loaded, were fixed with Knowles pins(six femora with three Knowles pins longitudinally and six femora with four Knowles pins quadriangularly) after femoral neck osteotomy and were loaded until internal fixation of femoral neck osteotomy failed(maximal loading force), while measuring strains on two spots of femoral neck. The ratio of strain on the same spot of the same femur between after and before femoral neck osteotomy was calculated. The author also observed the relationship between maximal loading force, difference of fixation method of Knowles pins and the ratio of strain between after and before femoral neck osteotomy. The results obtained are as follows : 1. In the femora of normal state, the tensile strain is higher on the antero-superior neck and the compressive strain on the poster on inferior neck of the femur. The strain on the mid-posterior neck was minimal. 2. In the twelve femora before femoral neck osteotomy, the ratio between the tensile strain on the antero-superior neck and the compressive strain on the postero-inferior neck in the same femur ranged from 29% to 92%, the mean value being 62±20.2%. 3. The ratio of the compressive strain on the cortex of the postero-inferior neck of the femur between after fixation of osteotomy and before osteotomy ranged from 47% to 210%, the mean value being 124±90.9% in six femora with three Knowles pins longitudinally and 128±70.6 % in the femora with four Knowles pins quadriangularly. 4. The ratio of the tensile strain on the cortex of the antero superior neck of seven femora, excluding five femora of disproportionally developed tensile strain, between after fixation of osteotomy and before osteotomy ranged from 25% to 80%. 5. The mean value of maximal loading force was 260±45.9Kp in six femora fixed with three Knowles pins longitudinally and 265±41.0Kp in six femora fixed with four Knowles pins quadriangularly. 6. The ratio of the compressive strain on the cortex of the posteroinferior neck of the femur between after fixation of osteotomy with and before osteotomy had close relationship with the maximal loading force. The maximal loading force had the mean value of 303±12.5Kp in six femora with the ratio less than 100%(47%70%) and the mean value of 221±16.9Kp in six femora with the ratio more than 100% (180%210%).

디지털 이미지 상관관계를 이용한 Al 6061-T6 인장시험편의 변형률 측정에 관한 연구

권오헌 ( Oh Heon Kwon ),김상태 ( Sang Tae Kim ),강지웅 ( Ji Woong Kang ) 한국안전학회(구 한국산업안전학회) 2013 한국안전학회지 Vol.28 No.4

A digital image correlation(DIC) method is a whole-field measurement technique that acquires surface displacements and strains from images information which characterized a random speckle as intensity grey levels. Recently years, this DIC method is being developed and used increasingly in various research. In this study, we tried to apply to aluminum alloy(Al 6061-T6) using DIC method and strain gauge. DIC results demonstrated the usefulness and ability to determine a strain. The test specimen used in this study was an aluminum alloy(Al 6061-T6, thickness 1 mm). For a strain measurement, a strain gauge was attached at the center of a specimen. A specimen was lightly sprayed with a white paint and a black dot pattern was sprayed on its fully dried white surface to obtain a random speckle. The experimental apparatus used to perform the tensile test consisted of universal dynamic tester(5 kN; T.O. Co.) under displacement speed of 0.5, 1.0 and 3.0 mm/min. A Model 5100 B Scanner(V. Co.) used to obtain a strain. A CCD camera connected to a PC uses to record the images of the specimen surface. After acquisition, the images were transferred to PC where the DIC software was implemented. An acquired image was evaluated by the DIC program. DIC method for displacement and strain was suggests and it results show a good consistent remarkably. DIC results demonstrated the usefulness and ability to determine surface strain was better than by using classical measurements. The strain field measurement using a DIC is so useful that it can be applied to map strain distributions at a full area. DIC method can evaluate a strain change so it can predict a location of fracture. The findings of the investigation suggest that the DIC method is an efficient and reliable tool for full-field monitoring and detailed damage characterization of materials.

Origin of the Strain Sensitivity for an Organic Heptazole Thin-Film and Its Strain Gauge Application

배희선,전표진,박지훈,이기문 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.8

The authors report on the origin of the strain sensitivity for an organic C26H16N2 (heptazole) thinfilm and its application for the detection of tensile strain. From the electrical characterization on the thin-film transistor adopting a heptazole channel, heptazole film exhibits p-channel conduction with a relatively low value of field-effect mobility (0.05 cm2/Vs), suggesting a hopping conduction behavior via hole carriers. By analyzing the strain and temperature dependences of the electrical conductivity, we reveal that the electrical conduction for a heptazole thin-film is dominated by the variable range hopping process with quite a large energy separation (224.9 meV) between the localized states under a relatively long attenuation length (10.46 Å). This indicates that a change in the inter-grain spacing that is much larger than the attenuation length is responsible for the reversible modification of electrical conductivity depending on strain for the heptazole film. By utilizing our heptazole thin-film both as a strain sensitive passive resistor and an active semiconducting channel layer, we can achieve a strain gauge device exhibiting reversible endurance for tensile strains up to 2.12%. Consequently, this study advances the understanding of the fundamental strain sensing mechanism in a heptazole thin-film toward finding a promise material with a strain gauge for applications as potential flexible devices and/or wearable electronics.

스트레인 게이지를 이용한 부직포의 변형거동 계측에 관한 연구

원명수,김유성,김형주,박병수 한국지반공학회 2007 한국지반공학회논문집 Vol.23 No.4

Because of the increasing use of clayey soil as the backfill in reinforced 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.

Strain gauge를 사용한 임플랜트 인상법의 정확도 비교

한인택,김영수,김창회,Han, Eu-Taek,Kim, Yung-Soo,Kim, Chang-Whe 대한치과보철학회 1995 대한치과보철학회지 Vol.33 No.3

The purpose of this study was to determine the accuracy of 3 implant impression methods by using strain gauge. The models used for this study were partially edentulous mandibular acrylic resin casts Model A, with two abutment analogs in #46,47 extraction site, represented two implant parallel to to the adjacent natural tooth. Model B represent an anterior implant parallel to the adjacene natural tooth and a posterior implant exhibiting a 15-degree lingual inclination. Master framework were fabricated on the master model, and 3 strain gauges were attached to a master framwork to determine the passivity of fit of the framework to sample casts made by the three impression techniques. The master framework was attached to each sample cast with gold screws, which were tightened with the torque driver to ensure a consistent toque application of 10 Ncm. Universal Digital Measuring System UCAM-5BT was used for strain measuring. Impression techniques studid were : 1. unsplinted tapered impression coping, polyvinyl siloxane, stock tray 2. unsplinted squared impression coping, polyether, custom tray 3. squared impression coping splinted with Duralay resin, polyether, custom tray Through analysis on data from this study, the following conclusions were obtained. 1. There were no statistically significant differences between the mean strain recorded from the sample casts made with the tree impression. But only strain values of model A(parallel group) Y-axis was signifcantly differed between Technique 1 and 3(P<0.05). 2. There was no statistically significant difference between model A(parallel group) and model B(15-degree divergent group).

Strain Gauge를 이용한 핀형 로드셀 개발

이동욱(Dong-Wook Lee),박민혁(Min-Hyuk Park),이계광(Gye-Gaong Lee),김인환(In-Hwan Kim),이석순(Seok-Soon Lee) 한국기계가공학회 2014 한국기계가공학회지 Vol.13 No.4

A pin-type load-cell which uses shear-type strain gauges was developed to measure the tension of a wire in a winch. A finite element analysis was performed to determine the locations of the strain gauges. All of the shear-type strain gauges were attached onto parts that undergo regularly shear stress distributions. A Wheatstone bridge circuit was used to connect each of the gauges and to measure the strains. Linearity within the 5% error range was noted when testing the pin-type load-cell.