• 한국강구조학회 논문집
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• 제14권6호
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• pp.721-728
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• 2002

현대 구조물의 고강도화, 경량화에 따라 구조물의 질량과 감쇠가 줄어들고 있어, 구조물의 진동사용성 문제가 중요하게 부각되고 있다. 특히 율동진동은 공연장, 경기장, 댄스홀, 에어로빅 등과 같이 다수이 군중의 리듬에 맞춰 가진행위가 이루어지는 것으로서, 국내에서도 율동진동에 의한 구조물의 진동문제가 다수 보고되고 있으나 설계기준 미비로 설계단계에서의 대응이 이루어지지 못하고 있다. 그러므로 본 연구에서는 다수의 점핑행위가 예상되는 공연장의 진동설계를 위하여 실제 공연장을 대상으로 진동실험 및 계측을 통하여 동하중계수를 구해냈다. 진동 실험은 실험모드해석과 더불어, 가진진동수별, 율동참여자의 숫자에 따라 실시하였으며, 진동계측은 상시계측시스템을 설치하여 실제 공연시 가속도 응답을 계측하고 동하중계수를 구해내었다. 기존의 NBCC 규준에서는 공연시 2차 조화항까지 고려토록 되어 있으나 연구결과 3차 조화항까지 고려해야 되며, 동하중계수 역시 과소평가 되어 있는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.105-111
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• 2003

The three-axis road simulator is the test equipment which can simulate the standardized road conditions for the durability evaluation of automotive components such as suspensions. The road load data are collected and acquired from a vehicle test, and then these data are used to simulate road load conditions by the road simulator which consists of hydraulic actuators, link mechanism and servo controller. The link mechanism must be designed in consideration of the dynamic effect and interference during three axes motions in order to generate accurate motions. In this paper, the structural and kinematic analysis of the link mechanism is performed, and these results can be used for developing the three-axis road simulator. The three-axis road simulator provides considerable savings in cost, development time, and testing risk during developing automotive components.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.80-91
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• 1998

In this paper, the estimation of dynamic interlaminar fracture toughness on fracture mode II in CFRP(carbon fiber reinforced plastics) laminates in made. Dynamic ENF(End Notched Flexure) apparatus used in this paper is manufactured by suing Split Hopkinson Pressure Bar. The static and impact load history in the CFRP specimen is measured by using manufactured dynamic ENF tester and 3-point bending test is carried out to find the load history. Also dynamic interlaminar fracture toughness can be found by using the J integral obrained from dynamic analysis in consideration of intertia-force effect.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.906-908
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• 2000

This paper presents dynamic modeling and simulation of induction motors. Equivalent circuit parameters measured by do test, no-load test and locked-rotor test were used as the input data for computer simulation. Operating characteristics of an induction motor were predicted by Matlab/simulink when changing load torque, opening and reclosing of phase a of the stator and three-phase fault at machine terminals.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.195-198
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• 2003

High temperature deformation and softening behavior of SAF 2507 super duplex stainless steel (SDSS) has been investigated in connection with an FEM analysis of hot forging process. Flow curves at various strain rates and temperatures were determined first from compression tests, and the kinetics of dynamic recrystallization were also formulated through the analysis of load relaxation test results. Applying the dynamic materials and proposed by Prasad et al., it was possible to determine the characteristics of deformation behavior effectively at a given condition of deformation. Constitutive relations and recrystallization kinetics formulated from the test results were then implemented in a commercial FEM code. Flow stress compensation formulated upon the volume fraction of recrystallization and adiabatic heating was found to improve significantly the FEA solutions in predicting the forming load and the distribution of recrystallized volume fraction after forging.

• 소성∙가공
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• 제12권4호
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• pp.308-313
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• 2003

High temperature deformation and softening behavior of SAF 2507 super duplex stainless steel (SDSS) has been investigated in connection with an FEM analysis of hot forging process. Flow curves at various strain rates and temperatures were determined first from compression tests, and the kinetics of dynamic recrystallization were also formulated through the analysis of load relaxation test results. Using the dynamic materials theory proposed by Prasad, the deformation behavior was effectively determined for various conditions. Constitutive relations and recrystallization kinetics formulated from the test results were then implemented in a commercial FEM code. The forming load as well as the distribution of recrystallized volume fraction after forging was successfully predicted by means of the flow stress compensation formulated upon the volume fraction of recrystallization and adiabatic heating.

• 한국지반환경공학회 논문집
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• 제20권3호
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• pp.31-38
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• 2019

PCFT말뚝의 하부에 PHC말뚝을 연결한 PCFT 복합말뚝에 대한 최적의 동재하시험 분석 방법을 도출하기 위하여 동일 현장에 시공된 강관 복합말뚝과 PCFT 복합말뚝에 대해 동재하시험을 실시한 후 CAPWAP분석 결과를 비교하였다. 그 결과 PCFT 복합말뚝에 대한 동재하시험 수행 시 변형률계와 가속도계는 상부 PCFT말뚝에서 강관을 제거한 후 내부 합성 PHC말뚝에 부착하는 것이 바람직하고, 이렇게 측정된 PCFT 복합말뚝의 입자 변위속도는 PHC말뚝 고유의 변형파 속도인 4,000m/sec과 동일하였다. 그리고 CAPWAP분석 시 PM과정을 통해 상부 PCFT말뚝의 재질을 PHC말뚝과 동일하게 하고 말뚝 단면적으로 콘크리트로 환산한 단면적을 사용했을 때 CAPWAP분석의 정확도가 가장 높은 것으로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.262-267
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• 2004

The unloading compliance method is the most commonly used method to evaluate the fracture resistance characteristics of a material. In dynamic loading condition, the direct current potential drop(DCPD) method has been used because the unloading compliance method can not be applied due to the discontinuity of loading. However, even in the dynamic test using DCPD method, there is a problem that the voltage drops sharply on the initiation of crack. For the reason metioned above, the normalization method was suggested on ASTM E 1820 which is revised recently, as a new method to evaluate the dynamic fracture resistance characteristic. The nomalization method can be used to obtain a fracture resistance curve directly from a load-load line displacement. In this study, we obtained two fracture resistance curves from static test of welding part of nuclear piping both by unloading compliance and nomalization method. The two curves were almost same each other, so the adaptability of the nomalization method has been proved. We conducted a dynamic fracture resistance test for the same material. The fracture resistance curve from the dynamic test was obtained by normalization method and compared to that of the static test result.

• 대한토목학회논문집
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• 제32권4A호
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• pp.245-253
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• 2012

본 연구에서는 장대터널이나 지하차도 등에 시공되는 횡류식 환기시스템을 구성하는 내화패널이 부착된 프리캐스트 풍도슬래브의 구조성능을 평가하기 위해서 실물모형 구조실험을 수행하였다. 또한, 내화패널의 휨강도와 Pull-off test를 통하여 내화패널과 슬래브의 부착성능 등의 기초성능을 우선적으로 확인하였다. 실물모형시험은 내화패널과 프리캐스트 PSC 슬래브의 정적 휨성능과 차량의 통행 시 발생하는 표면압력 이상의 하중에 대한 동적피로부착성능을 평가하였다. 동적피로하중 시험에서 내화패널과 PSC 슬래브 사이의 탈락이나 손상은 발생하지 않았으며, 정적재하시험에서도 매우 안정적인 거동을 보였으며, 하부에 부착된 내화패널의 탈락은 발생하지 않았다. 따라서 시공 중이나 시공 후 외부하중에 의해 내화패널의 탈락은 발생하지 않을 것으로 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1819-1826
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• 2007

This study results of performed field load test in order to estimate the best pile length assessment and allowable bearing capacity of the pile foundation. End of initial driving(EOID) and restrike of pile dynamic loading tests were performed to calculate allowable bearing capacity of the experimental pile side and results were compared with the allowable bearing capacity estimated by theory. The results of allowable bearing capacity by EOID test is $1.08{\sim}1.21$ in the range of compared to the capacity calculated by the Structure Foundation Design Criterion. Allowable bearing Capacity by restrike of pile dynamic loading test is $1.32{\sim}1.48$ in the range of compared to the Structure Foundation Design Criterion. The Foundation Design Criterion underestimated the pile capacity. If the bearing capacity calculated by Structure Foundation Design Criterion is 100, EOID of pile dynamic loading test is 116, restrike of pile dynamic loading test is 138 for 20m pile used in this experimental.