• 제목/요약/키워드: Dynamic fatigue test

검색결과 220건 처리시간 0.04초

피로에 따른 PSC거더의 동적특성 변화 (Dynamic characteristic change of a PSC girder due to fatigue)

  • 최상현;이창수;신기훈;김태균
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 춘계학술대회 논문집
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    • pp.1533-1538
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    • 2011
  • The dynamic characteristics such as resonant frequencies and dampings have been utilized as important parameters in dynamic behavior and inverse analyses. In general, the dynamic parameters have been determined based on design and experimental data, but experimental studies on the time-dependent changes of the dynamic parameters during service have rarely been conducted. Especially, unlike highway bridges, it is much easier for railroad bridges to estimate accumulated amount of fatigue because of the controlled train operation, and the study of dynamic characteristic change due to fatigue is useful, since it can enhance the accuracy of dynamic analysis. In this paper, the dynamic characteristic change due to fatigue is measured via the modal test on the PSC girder during a fatigue test. The test specimen utilized in the test is the IT girder which enhances the sectional capacity of the conventional PSC girders. The test specimen is designed 10m long and the modal tests are conducted during the application of fatigue load two million times. The test result shows that considerable changes in the measured dynamic parameters are observed as the fatigue accumulates, and these changes during the service life should be considered in designing railroad bridges.

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현장측정을 통한 분기기 망간 크로싱의 피로수명 평가 (Fatigue Life Evaluation for Railway Turnout Crossing using the Field Test)

  • 엄주환;최정열;박용걸
    • 한국철도학회논문집
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    • 제9권2호
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    • pp.169-173
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    • 2006
  • The major objective of this study is to investigate the fatigue life evaluation of immovability crossing for railway turnout by the field test. In railway engineering, an appliance is necessary to allow a vehicle to move from one track to another. This appliance came to be known technically as turnout. So, turnout is required very complex railway technologies such as rolling stock, track. Due to the plan under the application of high speed train, turnout are needed more stable far fatigue behaviors. It analyzed the mechanical behaviors of turnout crossing with propose its advanced technical type on the field test and fatigue evaluation far the dynamic fatigue characteristics. As a result, the advanced type crossing are obviously effective for the fatigue damage ratio and dynamic response which is non-modified type. The analytical and experimental study are carried out to investigate the passing path of contact surface and fatigue damage trend decrease dynamic stresses and deflections on advanced crossing type, And the advanced type reduce dynamic fatigue damage ratio and increase fatigue life(about each 38%) more than non-modified type. From the field test results of the servicing turnout crossing, it is evaluated that the modification of contact angle, weight, material and sectional properties is very effective fur ensure against fatigue risks.

현장측정을 통한 분기기 망간 크로싱의 피로거동 평가 (Fatigue Behavior Evaluation for Railway Turnout Crossing using the Field Test)

  • 송선옥;엄맥;양신추;박용걸
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2006년도 추계학술대회 논문집
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    • pp.447-453
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    • 2006
  • The major objective of this study is to investigate the fatigue behavior evaluation of immovability crossing for railway turnout by the field test. In railway engineering, an appliance is necessary to allow a vehicle to move from one track to another. This appliance came to be known technically as turnout. So, turnout is required very complex railway technologies such as rolling stock, track. Due to the plan under the application of high speed train, turnout are needed more stable for fatigue behaviors. It analyzed the mechanical behaviors of turnout crossing with propose its advanced technical type on the field test and fatigue evaluation for the dynamic fatigue characteristics. As a result, the advanced type crossing are obviously effective for the fatigue damage ratio and dynamic response which is non-modified type. The analytical and experimental study are carried out to investigate the passing path of contact surface and fatigue damage trend decrease dynamic stresses and deflections on advanced crossing type. And the advanced type reduce dynamic fatigue damage ratio and increase fatigue life(about each 38%)more than non-modified type. From the field test results of the servicing turnout crossing, it is evaluated that the modification of contact angle, weight, material and sectional properties is very effective for ensure against fatigue risks.

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도시철도차량 알루미늄 차체의 동적 하중 시험에 의한 피로 강도 평가 (Fatigue Strength Evaluation of the Aluminum Car body of Urban Transit Unit by Large Scale Dynamic Load Test)

  • 서승일;박춘수;신병천
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.1051-1055
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    • 2003
  • Aluminum carbody for rolling stocks is light and perfectly recycled, but includes severe defects which are very dangerous to fatigue strength. Structural integrity assessment for the carbody by static load test has been performed up to date. In this study, to evaluate fatigue strength of the aluminum carbody of urban transit unit. a testing method to simulate dynamic loading condition was proposed and the fatigue strength of the carbody was evaluated. The dynamic load test results showed that the alternating stress ranges were different from the estimated ranges based on the static test results. Excessive stress ranges at the center are thought to come from the flexible motion of the carbody. published fatigue test data for aluminum components, but variation of alternating acceleration along the length due to flexibility of carbody yielded unexpected results. Because fatigue strength based on the static test results may be overestimated at the center, modification of testing method is necessary.

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유니버설조인트 시험방식을 이용한 치과용 임플란트의 피로시험 및 가속수명시험에 관한 연구 (Study on the Fatigue Test and the Accelerated Life Test for Dental Implant using Universal-Joint Test Type)

  • 도경훈;이석진;김종미;김성민
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제17권1호
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    • pp.50-57
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    • 2017
  • Purpose : This paper is a comparative analysis results of the fatigue test for dental implants and accelerated life test by using a static type loading device commonly used in Korea and a dynamic type loading device (universal-joint) recommended by FDA. Methods : Fatigue tests of dental implant is based on ISO 14801 and classified into static load test and dynamic load test. The tests were carried out on three test specimens by four load stress steps under each loading device. For analysis on failure mode such as crack, fracture and permanent deformation of test specimens, we used X-ray three-dimensional computed tomography on test specimens before and after the fatigue tests. The design of the accelerated life test was based on the analysis results of the fatigue life data obtained from the dynamic load test and the statistical analysis software (Minitab ver.15) was used to analyze the appropriate life distribution. Results : As a result of the fatigue tests and the accelerated life tests at same acceleration condition under each test method, the fatigue life under the dynamic type loading device (universal-joint) was shorter than when static type loading device was applied. Conclusion : This paper can be used as a reference when the universal-joint type loading device for implants fatigue test is applied as ISO 14801.

알루미늄 차체 하중 시험 방법에 관한 비교 평가 (Comparison and Evaluation of Load Test Methods for Aluminum Car Body)

  • 서승일;박춘수;신병천
    • 한국철도학회논문집
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    • 제7권1호
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    • pp.32-36
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    • 2004
  • Aluminum carbody for rolling stocks is light and perfectly recycled, but includes severe defects which are very dangerous to fatigue strength. Static load test has been performed up to date to assess structural safety of the carbody. However, static load test is not sufficient to evaluate fatigue strength of the carbody, because fatigue failure is caused by dynamic load. In this study, the established load test methods for carbody are described and the characteristics of the methods are discussed. Also, a testing method to simulate dynamic loading condition is proposed for evaluation of fatigue strength of the carbody. The results by the proposed testing method are compared with the results by the static load test and new findings are discussed.

OHT 차량 벨트 동특성 및 피로 수명에 관한 연구 (A Study on Dynamic Analysis and Fatigue Life of the Belt in the OHT Vehicle)

  • 정일호;김창수;조동협;박중경;박태원
    • 대한기계학회논문집A
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    • 제29권8호
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    • pp.1085-1092
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    • 2005
  • The OHT(Over Head Transportation) Vehicle transports heavy products quickly and repeatedly at the industrial workplace. The belt in the OHT vehicle is used to support the weight of the OHT Cage. The fatigue of the belt is caused by the dynamic load during the operation time. Since the fatigue fracture of the belt affects the safety at the workplace, the correct prediction of the dynamic load is necessary to calculate the fatigue life of the belt on the design step. In this paper a computer aided analysis method is proposed for the belt in the early design stage using dynamic analysis, stress analysis, belt tensile test, belt fatigue test and fatigue lift prediction method. From the dynamic load time histories and the stress of the belt FE model, a dynamic stress time history is produced. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The method developed in this paper is used to reduce the time and cost for designing the OHT belt in different environment and condition.

다이나믹 테이핑과 키네시오 테이핑 적용에 따른 발바닥 굽힘근의 지구력과 피로도에 미치는 효과 비교 (Comparison of the effects of dynamic taping and kinesio taping on endurance and fatigue of plantar flexor)

  • 송준영;박삼호;이명모
    • 대한물리치료과학회지
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    • 제29권1호
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    • pp.73-86
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    • 2022
  • Background: The purpose of this study is to investigate the effect of plantar flexor on muscle fatigue and endurance when two different sport tapes are applied. Design: Cross-sectional design. Methods: Fifty-one healthy adults were randomly assigned to dynamic taping group (n=17), kinesio taping group (n=17), and control group (n=17). The dynamic taping group used the dynamic tape. The kinesio tape group used the kinesio tape, and the control group doesn't used tape. Every group performed heel rise test and sEMG for every during pre-test and post-test. To evaluate plantar flexor endurance, the number of times was measured during the heel rise test. Results: The number of heel rises increased significantly in the post-test in dynamic taping group compared to the pre-test, and In comparison between groups, the number of heel rises significantly increased in dynamic taping group compared to kinesio taping group and control group. PEF value was significantly increased in the post-test compared to the pre-test in dynamic taping group, and there was a significant difference between the three groups according to the taping application. Conclusion: The results of this study confirmed that dynamic taping was effective in musclular fatigue and endurance on plantar flexor in healthy adults. Based on these results, it is suggested that the application of dynamic tape can be suggested as one of the intervention methods for muscle endurance and muscle fatigue.

고장력 강판의 초음파 피로시험 (Ultrasonic Fatigue Test for a High Strength Steel Plate)

  • 염현호;정용찬;김차영;강기영;이문구;홍민성;전용호
    • 한국생산제조학회지
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    • 제24권6호
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    • pp.589-593
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    • 2015
  • The demand of high cycle fatigue behavior on plate material is increasing because of its various applications. However, the high-cycle fatigue life data of the plate material is very rare compared to the rod material. Thus, in this study, a plate specimen is designed for the ultrasonic fatigue test because it is time efficient as compared to the conventional fatigue test. To apply the ultrasonic fatigue test, the specimen design is required to resonate at 20 kHz. Therefore, the dynamic elastic modulus was determined by measuring the resonance frequency with a piezoelectric element and laser doppler vibrometer (LDV). As a result, the plate specimen is designed and demonstrated using the ultrasonic fatigue testing machine. The ultrasonic fatigue test results were compared with the hydraulic fatigue test results.

실내 모형반복실험에 의한 철도노반재료의 성능 평가 (Evaluation of Performance of the Railroad Roadbed Material by Model Fatigue lest)

  • 황선근;이성혁;이시한;최찬용
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 봄 학술발표회 논문집
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    • pp.191-198
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    • 2000
  • Dynamic fatigue test is carried out using soil model box for the evaluation of performance of three different roadbed materials. Bearing capacity, settlement and mud pumping phenomenon of each roadbed materials as well as penetration of model ballast into the roadbeds are investigated. It was found that settlement of slag and crushed stone roadbed is smaller than the soil roadbed during dynamic fatigue test with same initial conditions.

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