• Title/Summary/Keyword: stability test

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Verification Study of Moving Load Simulation Test in Railroad Bridge (철도교량 주행하중 재현 시험 검증)

  • Kim, Hyun-Min;Kim, Sung-Il;Kim, Tae-Hoon
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1562-1568
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    • 2011
  • This paper is intended as an verification of moving load simulation techniques. The concern with dynamic problem of railway bridge caused by the moving train loads has been growing. Over the past few years, several studies have been made on dynamic stability of railway bridge analytically. But very few attempts have been made at experimental research. From the dynamic stability view point, the moving train loads simulation test is revolutionary idea. It can be replace restrictive filed test with new laboratory test. This study investigates minimum specifications of hardware and basic parameters. it is used 12m girder and high performance actuator for experimental verification.

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A Study on the Development and Performance Evaluation of an ATC Test Bench (ATC Test Bench 개발 및 성능평가에 관한 연구)

  • Kim, Jae-Hyun;Choi, Jun-Young;Lee, Choon-Man
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.5
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    • pp.489-493
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    • 2012
  • Automatic tool changers(ATCs) store tools used in a machining center to its magazine and changes the tools automatically. Tools of machine centers are changed and then precisely equipped to spindle system by the ATC. Therefore, the stability and reliability of the ATC is very important. But, there is lack of development and evaluation on basic performance and vibration of the ATCs. So, in this study, a BT40 ATC test bench was developed to verify stability and reliability of BT40 ATCs.

Design & system construction of insulation on the traction motor for EMU (철도차량용 견인전동기의 절연설계 및 절연시스템 구성)

  • 왕종배;홍선호;조연옥;김명룡
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.194-197
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    • 2001
  • Traction motors driven by high speed switching inverters is demanded higher operating temperature, severe duty cycles, higher starting current, frequent voltage transients and finally severe environmental exposure. For applications to inverter duty, traction motors needs a special insulation system, which has characteristics of increased bond strength, lower operating temperature and higher turn-to-turn insulation. In this paper, design considerations and manufacturing procedure of 200 Class insulation system with polyimde(Kapton) main insulation and silicone resin VPI process on the traction motor for EMU will be reviewed. And performance test and long life evaluation test which prove stability and long life evaluation test which prove stability and reliability of insulation system for traction motor will be introduced.

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Friction and Wear Characteristics of Friction Material with the Content of Hexamethylenetetramine (Hexamethylenetetramine의 함량에 따른 마찰재의 마찰.마모 특성)

  • Kim, Dae-Kyeun;Jang, Ho;Yoon, Ho-Gyu
    • Tribology and Lubricants
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    • v.16 no.4
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    • pp.266-273
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    • 2000
  • The friction characteristics of phenolic resin and model friction materials were investigated with the content of hexamethylenetetamine (HEXA). At 10 wt.% of HEXA, the phenolic resin and model friction materials showed the most stable friction coeffcient in constant temperature test at various test conditions because of its good thermal stability and proper curing reaction. It was found from constant interval test in mild condition that the friction coeffcients of friction materials cured with 10 wt.% of HEXA was the highest and stable values in the whole range of braking operations. However, at the severe condition in constant interval test, the friction coefficient of friction materials cured with 10 wt.% to of HEXA was lowered and as the number of braking operation increased, the values became stable. In order to obtain the thormal stable friction materials, the content of HEXA from 5 to 10 wt.% could be recommended.

An Dredging Depth Calculation of a Pile Under Lateral Loading Based on Model Test (모형실험을 통한 횡하중을 받는 말뚝의 준설깊이 산정)

  • Yoo, Chan-Ho;Lee, Jung-Jae;Kim, Seung-Wook;Chung, Jong-Min;Kim, Hong-Taek
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1094-1103
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    • 2010
  • The safety of pile foundation is getting declined when the pile foundation acting on lateral load is exposed by dredging. So appropriate reinforcement is needed for stability secure. Thus, in this study, the stability variation and reinforcement range caused by dredging is estimated on the basis of down scale test. The scale effect is determined by real scale numerical analysis. the behavior of pile by dredging stages is estimated by load control type. The credibility is verified through the comparison between down scale model test and numerical analysis.

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A Study on the Principal Performance of Purse Seiner Ship in 2 Vessels Formation (2척 선단 선망본선의 주요성능에 관한 연구)

  • 최낙경;강병윤;조효제
    • Journal of Ocean Engineering and Technology
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    • v.16 no.6
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    • pp.71-75
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    • 2002
  • In this paper, a study on the principal performance of the purse seiner ship in two vessel formations was conducted. For this task, the outline of the purse seiner fishing system in two vessel formations was reviewed. At the same time, based on the general arrangement plan, hull from of the main vessel was developed. And the stability and ship motion characteristics of the ship design were estimated. Finally, to verify the characteristics of the resistance and self-propulsion coefficient, a model test in a circulating water channel was performed. As n result, it is anticipated that this presentation will be used as the foundation material for research of purse seiner.

A Study on Proficiency Test Sample Development for Environmental & Reliability Testing Field (환경 및 신뢰성 시험분야를 위한 숙련도시험 시료개발 연구)

  • PARK, Kyunghwan;LEE, Cheolgyu
    • Journal of Korean Society for Quality Management
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    • v.45 no.3
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    • pp.447-462
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    • 2017
  • Purpose: This study aims to develop distributable samples that can be used for proficiency testing to verify the ability of the testing laboratory to perform high temperature and low temperature tests. Method: In this study, the temperature-resistance characteristics of the NTC thermistor were used to develop samples. The homogeneity and stability of samples were examined according to the proficiency testing requirements. Results: Thirty samples with homogeneity and stability were developed and used for the proficiency testing. Thus, it was possible to distinguish between the test laboratories that showed satisfactory results and those that did not. Conclusion: It was the first time to develop samples that can be used for proficiency testing in high temperature and low temperature tests. and it was proved that the proficiency test program can be operated using the characteristics of NTC thermistor.

Evaluation on stability of scour countermeasures using geobag and recycled aggregates (재생골재를 활용한 지오백 세굴보호공법의 안정성 평가)

  • Lee, Ju-Hyung;Park, Jae-Hyun;Chung, Moon-Kyung;Kwak, Ki-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.233-244
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    • 2009
  • A new bridge scour countermeasure using geobags and recycled aggregates which is more stable and economical than existing methods is proposed, and its stability was verified through material tests. PP short staple nonwoven geotextile and PET long staple nonwoven geotextile produced in Korea were selected, and a series of strength tests and a test of hydraulic characteristics were conducted to determine a suitable geotextile for geobags. A series of leaching test was also conducted to assess the potential environmental risk of recycled concrete produced in Korea when it is utilized as a material for protecting bridge piers against scour.

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Full Scale Load Tests on Reinforced Slope Structure (사면보강구조물에 대한 실물재하시험과 평가)

  • Kwon, Young-Ho;Park, Shin-Young;Lee, Seung-Hyun;Kang, In-Kyu;Ki, Min-Ju
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.10a
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    • pp.241-255
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    • 2006
  • Owing to a landslide or embankment damage be caused by a localized torrential downpour and heavy snowfall resulted from recent abnormal climate, a slope stability is very important. This study is investigate a general slope reinforcement method and applicability improvement of soil nailing method utilized prototype loading test for the facing stiffness effect confirmation. A prototype loading test supplements general slope stability study by numerical analysis or laboratory test with a resonable analysis of slope structure.

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Mandibular arch orthodontic treatment stability using passive self-ligating and conventional systems in adults: A randomized controlled trial

  • Rahman, Norma Ab;Wey, Mang Chek;Othman, Siti Adibah
    • The korean journal of orthodontics
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    • v.47 no.1
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    • pp.11-20
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    • 2017
  • Objective: This randomized controlled trial aimed to compare the stability of mandibular arch orthodontic treatment outcomes between passive self-ligating and conventional systems during 6 months of retention. Methods: Forty-seven orthodontic patients with mild to moderate crowding malocclusions not requiring extraction were recruited based on inclusion criteria. Patients (mean age $21.58{\pm}2.94years$) were randomized into two groups to receive either passive self-ligating ($Damon^{(R)}$ 3MX, n = 23) or conventional system (Gemini MBT, n = 24) orthodontic treatment. Direct measurements of the final sample comprising 20 study models per group were performed using a digital caliper at the debonding stage, and 1 month, 3 months, and 6 months after debonding. Paired t-test, independent t-test, and non-parametric test were used for statistical analysis. Results: A significant increase (p < 0.01) in incisor irregularity was observed in both self-ligating and conventional system groups. A significant reduction (p < 0.01) in second interpremolar width was observed in both groups. Mandibular arch length decreased significantly (p = 0.001) in the conventional system group but not in the self-ligating system group. A similar pattern of stability was observed for intercanine width, first interpremolar width, intermolar width, and arch depth throughout the 6-month retention period after debonding. Comparison of incisor irregularity and arch dimension changes between self-ligating system and conventional system groups during the 6 months were non-significant. Conclusions: The stability of treatment outcomes for mild to moderate crowding malocclusions was similar between the self-ligating system and conventional system during the first 6 months of retention.