• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.844-848
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• 2004

We evaluate the durability of vehicle chassis component under dynamic loadings. Since the fatigue analysis of vehicle component is based on the dynamic load history it must be done by dynamic analysis. But in case the vehicle component has natural frequencies much larger than reversing frequencies of load history, we can get small analysis errors by applying quasi-static analysis. So it is inefficient that we apply to the dynamic analysis for all the vehicle components. In this research, we discuss the quasi-static analysis method which is appropriate for the fatigue analysis. And in case we can only perform the fatigue analysis based on dynamic analysis, we introduce more efficient method in the analysis time and hard disk storage.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2220-2227
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• 2000

In this paper, dynamic photoelastic hybrid method is developed and its validity is certified. The dynamic photoelastic hybrid method can be used on the obtaining of dynamic stress intensity factors and dynamic stress components. The effect of crack length on the dynamic stress intensity factors is less than those on the static stress intensity factors. When structures are under the dynamic mixed mode load, dynamic stress intensity factor of mode I is almost produced. Dynamic loading device manufactured in this research can be used on the research of dynamic behavior when mechanical resonance is produced and when crack is propagated with the constant velocity.

• 전산구조공학
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• 제10권3호
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• pp.145-155
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• 1997

본 연구에서는 ANSYS와 ABAQUS 상용 유한요소 코드를 이용하여 궤도차량의 정적.동적 해석을 충격하중과 주행하중에 대해서 수행하였다. 궤도차량이 충격하중을 받을 때 최대 동적 Von Mises응력은 상판의 빔보강재와 레이스링사이에서 발생하였으며 응력수준은 390-450MPa이다. 정하중에 대한 동하중수 1.6을 고려했을 경우 동적 해석과 동적하중계수가 포함된 정하중 해석은 유사한 결과를 보이고 있다. 과도응력은 주로 레이싱링 주위에서 발생하고 있다. 주행하중의 경우 최대응력은 로드휠 유기압 현가장치 #1번에서 450MPa정도이며, 정적해석과 비선형 해석의 결과가 유사하다.

• 한국구조물진단유지관리공학회 논문집
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• 제21권3호
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• pp.60-68
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• 2017

교량은 사회간접시설물의 핵심이 되는 도로의 주요 시설물이므로 공용기간 동안 안정성과 사용성이 확보될 수 있도록 건설되며, 교량의 안전성 확보를 위하여 현재 상태에서 건전성을 평가하는 것은 유지관리 업무에서 중요한 과제이다. 일반적으로 교량의 내하력 평가를 위해 차량재하시험을 통하여 횡분배율을 측정함으로써 교량의 중첩거동 및 대칭거동을 확인할 수 있다. 그러나 공용중인 교량의 횡분배율을 측정하기 위하여 정적재하시험을 수행하고 있으며 교통통제의 어려움이 있다. 따라서 본 연구에서는 동적재하시험 및 상시진동시험에서 측정된 교량의 변위응답 데이터를 경험적 모드분해기법을 이용하여 정적 성분의 변위를 추출하였다. 추출된 정적 성분의 변위를 이용하여 횡분배율을 추정하였으며, 정적재하시험에서 측정된 횡분배율과 비교하였다.

• Steel and Composite Structures
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• 제22권3호
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• pp.677-690
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• 2016

In this paper, the effect of damping ratio on nonlinear dynamic analysis response and dynamic increase factor (DIF) in nonlinear static analysis of structures against column removal are investigated and a modified empirical DIF is presented. To this end, series of low and mid-rise moment frame structures with different span lengths and number of storeys are designed and the effect of damping ratio in DIF is investigated, performing several nonlinear static and dynamic analyses. For each damping ratio, a nonlinear dynamic analysis and a step by step nonlinear static analysis are carried out and the modified empirical DIF formulas are derived. The results of the analysis reveal that DIF is decreased with increasing damping ratio. Finally, an empirical formula is recommended that relates to damping ratio. Therefore, the new modified DIF can be used with nonlinear static analysis instead of nonlinear dynamic analysis to assess the progressive collapse potential of moment frame buildings with different damping ratios.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1631-1635
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• 2011

To consider dynamic magnification effect at the static design stage, impact load factor is applied to design load. Current impact load factor adopted EUROCODE without verification while Japan suggested impact load factor including velocity of high-speed train throughout theoretical and experimental studies. On the purpose of evaluate current impact load factor, this study investigated the calculation of impact load factor from dynamic response of running train.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.845-851
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• 2012

Power system loads have a significant impact on a system. Although it is difficult to precisely describe loads in a mathematical model, accurately modeling them is important for a system analysis. The traditional load modeling method is based on the load components of a bus. Recently, the load modeling method based on measurements from a system has been introduced and developed by researchers. The two major components of a load modeling problem are determining the mathematical model for the target system and estimating the parameters of the determined model. We use the composite load model, which has both static and dynamic load characteristics. The ZIP model and the induction motor model are used for the static and dynamic load models, respectively. In this work, we propose the measurement-based parameter estimation method for the composite load model. The test system and related measurements are obtained using transient security assessment tool(TSAT) simulation program and PSS/E. The parameter estimation is then verified using these measurements. Cases are tested and verified using the sample system and its related measurements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.370-374
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• 1991

This paper presents a static circuit model for static ant dynamic simulation of induction motors and identification of motor parameters. Instead of usual T-circuits, equivalent ${\pi}$-circuit has been proposed so that power Inputs into motor terminals can very easily calculated with very well known load flow method. It has been shown that, with wide range variation of applied voltage and frequency, successful static simulations can be performed and further the proposed static model can be used to simulate dynamic characteristics. Finally it is shown also that motor parameters can easily be identified based on the proposed static circuit.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.186-194
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• 2004

Experiments were conducted to determine the structural static and dynamic characteristics of air foil bearings. The housing of the bearing on the journal was driven by an impact hammer which was used to simulate dynamic forces acting on the bump loll with various leading condition. Two different bump foils (Cu-coated bump and viscoelastic bump) were tested and the static and dynamic coefficients of two bump foils compared, based on the experimental measurements for a wide range of operating conditions. The static and dynamic characteristics of air foil bearings were extracted 0rpm the frequency response function by least square method and IV(Instrumental Variable) method. The experiment was tested at 0rpm and $10,000\~16,000rpm$, and loaded on $50\~150N$. From the test results, the possibility of the application of high load and high speed condition is suggested.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.865-871
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• 2004

The safety evaluations of railway wheel sets make use of the static fracture toughness obtained in ingot materials. The static fracture toughness of wheelset materials has been extensively studied by experiments, but the dynamic fracture toughness with respect to wheel set materials has not been studied enough yet. It is necessary to evaluate the characteristics of the fracture mechanics depending on each location for a full-scale wheel set for high-speed trains, because the load state for each location of the wheel set while running is different the contact load between the wheel and rail, cyclic stress in the wheel plate, etc. This paper deals with the fracture toughness depend on load rates. The fracture toughness depending on load rate data shows that once the downward curve from quasi-static values was reached, subsequent values showed a slow increase with respect to the impact velocity. This means that dynamic fracture toughness should be considered in the design code of the wheelset material.