• Title/Summary/Keyword: Field Testing

Search Result 1,763, Processing Time 0.024 seconds

Low-Soil Disturbance In-Situ Test Method Development and Its Application : Screw Plate Loading Test (지반의 교란을 최소화 한 원위치시험법 개발 및 적용 : 스크류재하시험)

  • Lee, Yong-Su;Hwang, Woong-Ki;Choi, Yong-Kyu;Kim, Tae-Hyung
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2009.03a
    • /
    • pp.977-986
    • /
    • 2009
  • Sampling disturbance can introduce considerable errors in the laboratory estimation of geotechnical properties of soils, and the results obtained from sophisticated sampling and careful laboratory testing are not matching with field behavior. Therefore, it is advantage to adopt in-situ testing techniques for the estimation of geotechnical parameters. Therefore, Screw plate loading test, one of new field test technologies, has been investigated in this study. This test can be utilized to find out important properties of soils such as load-displacement, elastic modulus, and shear strength. The screw plate loading test modified from the plate loading test is an experiment underneath ground by inserting a spiral type of auger screw. The structure and characteristics of the screw plate loading test device was examined in detail. In addition, The new screw plate loading test device was manufactured to refer the previous studies. The reliability of developing screw plate loading test was examined through the analysis of the laboratory test.

  • PDF

Application of Amorphous wire to ECT(Eddy Current Testing) Probe (아몰퍼스 와이어의 ECT probe 적용에 대한 검토)

  • Kim, Y.H.;Shin, K.H.;SaGong, Gun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2002.08a
    • /
    • pp.47-51
    • /
    • 2002
  • ECT(eddy currentign testing) is very effective technique to detect a flaw within a conductor. Co-based amorphous wire was used as a sensor head. The wire has almost 0 magneto-striction and high permeability. An uniform magnetic field was applied to 1mm thick copper plate and $25{\mu}m$ thick aluminum sheet conductor using spiral typed coil The size of the coil has $40mm{\times}40mm$ outer width and $8mm{\times}8mm$ inner width. The copper plate and aluminum sheet has 0.5mm and 0.1mm wide gap, respectively. The frequency range of applied field was 100kHz-600kHz. The induced voltage difference of 2.5mV was obtained in the maximum voltage and minimum one measured across the gap of the 1mm thick conductor. In the case of aluminum sheet, 0.4mV was obtained. From this results, the effectiveness of Co-based amorphous wire was confirmed in the ECT technique.

  • PDF

Application of Ultrasonic Technique for Early-Aged PC Beams in Field (초음파 탐사법의 긴장 전 PC보에 대한 현장적용)

  • Lee, Jun-Ki;Park, Sung-Woo;Yoon, Jung-Sup;Park, Chul-Shin
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.589-592
    • /
    • 2008
  • Recently, as importance of quality control of the structure has been recognized, non-destructive testing, determining quality of the structure without damage, has been widely applied. However, its application has been primarily focused on laboratory development because variety of parameters in field has been not fully experienced and understood. This study aims to evaluate the field applicability of the ultrasonic testing method for PC beams. Material properties of 18 cylinders, cured in the same field condition, were measured up to 60 days and compared to those of the ultrasonic measurements from 34 PC beams in field before tensioning. Test results indicate that uni-axial strength and elastic modulus of PC beams can be predicted within reasonable range using the ultrasonic technique. However, it is also noted that considerations on field condition is required to increase the reliability of estimation.

  • PDF

A study on the frequency sharing TA Radio with the RFID in the 900MHz band (900MHz대역에서 TA Radio와 RFID의 주파수 공유에 관한 연구)

  • Moon, Hun-Il;Yu, Seung-Duk;Hong, Wan-Pyo
    • Journal of Advanced Navigation Technology
    • /
    • v.14 no.3
    • /
    • pp.367-374
    • /
    • 2010
  • In this paper, the frequencies sharing possibility between TA(TalkAround) Radios and RFID system in 900MHz frequency band have been studied. The modulation technic for FHSS(Frequency Hopping Spread Spectrum) of TA is digital FSK and RFID system adapts digital ASK modulation technic. The communication mode of the tested RFID system for frequencies sharing possibility was FHSS. The field test was performed by five scenarios. The RFID field testing system for the frequencies sharing possibility was composed of four tags and two main devices made in USA. Four TA and Egilant spectrum analyzer was used for testing. The frequencies sharing possibility by differentiated modulation was theoretically analyzed. As result of simulation, it was proved that the frequencies sharing between each other modulation system is possible. And also as result of field testing it was confirmed that the signal of TA Radios have no effect on the signal of RFID system.

Analysis of Ethernet Wwitch Measurement Uncertainty for KOLAS Testing Laboratory Accreditation (KOLAS 공인시험기관 인정을 위한 이더넷 스위치의 측정불확도 분석)

  • Lee, Jae-Jeong;Ryu, Han-Yand;Nam, Ki-Dong;Kim, Chang-Bong
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.48 no.12
    • /
    • pp.1-8
    • /
    • 2011
  • Actively in progress in the field of general industrial KOLAS (Korea Laboratory Accreditation Scheme) accreditation test the switch, router, network equipment, such as accreditation status in the field can not be found. Company's self-tsting or BMT (Bench Marking Test) through the evaluation process for network equipment, but the test reports issued by accredited laboratories with quality differences. Requested by public institutions or other providers of accredited test reports increasing demand for network equipment in Korea accredited testing laboratory shall be made as soon as possible. In this paper, as required by KOLAS in the field of network equipment testing laboratory accreditation program in the process acquired through the analysis of measurement uncertainty and, to propose effective direction.

Field Application of a Cable NDT System for Cable-Stayed Bridge Using MFL Sensors Integrated Climbing Robot (누설자속센서를 탑재시킨 이동로봇을 이용한 사장교 케이블 비파괴검사 시스템의 현장 적용)

  • Kim, Ju-Won;Choi, Jun-Sung;Lee, Eun-Chan;Park, Seung-Hee
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.34 no.1
    • /
    • pp.60-67
    • /
    • 2014
  • In this study, an automated cable non-destructive testing(NDT) system was developed to monitor the steel cables that are a core component of cable-stayed bridges. The magnetic flux leakage(MFL) method, which is suitable for ferromagnetic continuum structures and has been verified in previous studies, was applied to the cable inspection. A multi-channel MFL sensor head was fabricated using hall sensors and permanent magnets. A wheel-based cable climbing robot was fabricated to improve the accessibility to the cables, and operating software was developed to monitor the MFL-based NDT research and control the climbing robot. Remote data transmission and robot control were realized by applying wireless LAN communication. Finally, the developed element techniques were integrated into an MFL-based cable NDT system, and the field applicability of this system was verified through a field test at Seohae Bridge, which is a typical cable-stayed bridge currently in operation.

Backward Testing Method of MTF measurement for optical engine of CRT of rear projection HDTV (후면투사식 CRT 고화질 텔레비전용 광학엔진의 변조전달함수 측정을 위한 후방검사 변조전달함수 측정법)

  • Song, Jong-Sup;Jo, Jae-Heung;Hong, Sung-Mok;Lee, Yun-Woo;Song, Jae-Bong;Lee, Hoe-Yun;Lee, In-Won
    • Korean Journal of Optics and Photonics
    • /
    • v.16 no.1
    • /
    • pp.56-62
    • /
    • 2005
  • Because of the wide plane and the curved field of CRT rear projection high definition television, its MTF(modulation transfer function) can't be easily measured by the usual forward testing method. Then we propose a backward testing method for the MTF so that the object plane and the image analyzer of forward testing are located at positions opposite each other. We prefer to use the backward testing method because the forward testing method has poor accuracy caused by very small numerical aperture, low spatial resolutions, and long depth of focus. We found that the backward testing method was very easy to align and had high repeatability. We confirmed the confidence of results obtained by the backward testing method in comparison with designed results.

IE-SASW Method for Nondestructive Testing of Geotechnical Concrete Structure : II. Experimental Studies (콘크리트 지반구조물의 비파괴검사를 위한 충격반향-표면파 병행기법 : II. 실험적 연구)

  • 김동수;서원석;이광명
    • Journal of the Korean Geotechnical Society
    • /
    • v.18 no.4
    • /
    • pp.271-283
    • /
    • 2002
  • P-wave velocity of concrete is a crucial parameter in determining the thickness of concrete lining, the location of cracks or other defects in Impact-Echo(IE) method. This study introduces an IE-SASW method that may determine the P-wave velocity on a surface of each testing area using the Spectral Analysis of Surface Wave (SASW) method. In numerical studies(Part I), it was verified that P-wave velocities could be obtained from SASW. In this paper(Part II), experimental studies were made in slab type concrete model specimens in which voids and waterproof sheet were included at the known locations. Accordingly, the feasibility of the proposed method was evaluated. The IE-SASW method was also performed in the precast model tunnel on ground and open-cut tunnel in ground. SASW tests were performed to determine the P-wave velocity of the concrete and then IE tests were carried at regularly spaced points along the testing lines to determine the thickness of structures. The nondestructive testing method which combined SASW and IE tests showed the great potential in the field applications.

Applying a Forced Censoring Technique with Accelerated Modeling for Improving Estimation of Extremely Small Percentiles of Strengths

  • Chen Weiwei;Leon Ramon V.;Young Timothy M.;Guess Frank M.
    • International Journal of Reliability and Applications
    • /
    • v.7 no.1
    • /
    • pp.27-39
    • /
    • 2006
  • Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.

  • PDF

Development and Reliability Verification of Quality Control System for Compaction Grouting Method (컴팩션 그라우팅 공법의 품질관리 시스템 개발 및 신뢰성 검증)

  • Seo, Seok-Hyun;Lee, Jung-Sang;Jung, Eui-Youp;Park, Sang-Yeong;Lee, Hyo-Bum
    • Journal of the Korean Geosynthetics Society
    • /
    • v.19 no.4
    • /
    • pp.11-20
    • /
    • 2020
  • This study introduced the compact grouting method that can be used for improving soft ground and restoring buildings with unequal subsidence. The pump used in the traditional compact grouting method is a system that injects one hole each, which reduces the construction efficiency, and the analog injection method manually manages the construction by field workers, making it difficult to manage consistent quality. Pump and quality control system were developed to solve problems in existing construction. Since field supervisor determines amount of injected materials by using analog equipment and controls manually, it is difficult to manage consistent quality of construction. Therefore, the quality control system was developed in order to solve that problem. The quality control system consists of automatic mixing system of injection materials, multiple simultaneous injection pumps, and injection management monitoring system. Performance of the quality control system was verified through on-site testing, and ground improvement performance was verified through quality testing after testing and testing of the compact grouting method. Therefore, it is expected that the integrated quality control system developed will improve the quality assurance and efficiency and stability of construction at sites where construction and quality verification are difficult.