• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.56-62
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• 2017

Although most electricity production contributes to air pollution, the vehicle organizations and environmental agency categorizes all EVs as zero-emission vehicles because they produce no direct exhaust or emissions. Currently available EVs have a shorter range per charge than most conventional vehicles have per tank of gas. EVs manufacturers typically target a range of 160 km over on a fully charged battery. The energy efficiency and driving range of EVs varies substantially based on driving conditions and driving habits. Extreme outside temperatures tend to reduce range, because more energy must be used to heat or cool the cabin. High driving speeds reduce range because of the energy required to overcome increased drag. Compared with gradual acceleration, rapid acceleration reduces range. Additional devices significant inclines also reduces range. Based on these driving modes and climate conditions, this paper discusses the performance characteristics of EVs on energy efficiency and driving range. Test vehicles were divided by low / high-speed EVs. The difference of test vehicles are on the vehicle speed and size. Low-speed EVs is a denomination for battery EVs that are legally limited to roads with posted speed limits as high as 72 km/h depending on the particular laws, usually are built to have a top speed of 60 km/h, and have a maximum loaded weight of 1,400 kg. Each vehicle test was performed according to the driving modes and test temperature ($-25^{\circ}C{\sim}35^{\circ}C$). It has a great influence on fuel efficiency amd driving distance according to test temperature conditions.

• Structural Engineering and Mechanics
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• 제40권4호
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• pp.453-469
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• 2011

A one-story, wooden-frame, intermediate-bay model with Dou-Gon designed according to the Building Standards of the Song Dynasty (A.D.960-1279), was tested on a unidirectional shaking table. The main objectives of this experimental study were to investigate the seismic performance of Chinese historic wooden structure under various base input intensities. El Centro wave (N-S), Taft wave and Lanzhou wave were selected as input excitations. 27 seismic geophones were instrumented to measure the real-time displacement, velocity and acceleration respectively. Dynamic characteristics, failure mode and hysteretic energy dissipation performance of the model are analyzed. Test results indicate that the nature period and damping ratio of the model increase with the increasing magnitude of earthquake excitation. The nature period of the model is within 0.5~0.6 s, the damping ratio is 3~4%. The maximum acceleration dynamic magnification factor is less than 1 and decreases as the input seismic power increases. The frictional slippage of Dou-Gon layers (corbel brackets) between beams and plates dissipates a certain amount of seismic energy, and so does the slippage between posts and plinths. The mortise-tenon joint of the timber frame dissipates most of the seismic energy. Therefore, it plays a significant part in shock absorption and isolation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.537-540
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• 1992

This paper presents Samsung CNC (Computer Numerical Controller) system with an intel 80486/487 as the main CPU and a 32 bit floating point DSP(Digital Signal Processor) TMS320C30 as the motion control CPU. The Samsung CNC system diverse user-frienly characteristics such as multi-tasking, powerful menu system, internal PLC system, and 2/3 dimensional graphics in wire and solid mode. The main CPU executes central processing program, user interface program, interpreter, BMI, etc while the motion control CPU carries out some interpolations, acceleration/deceleration, and PID control algorithm with feedforward terms. Complex interpolations except linear and circular ones are performed on the main control CPU. The experimental results for the circular interpolation under linear acceleration/deceleration shows that the proposed CNC system can be widely used in controlling machining centers with good machining accuracy.

• Structural Engineering and Mechanics
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• 제29권5호
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• pp.505-530
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• 2008

This paper proposes the application of active multiple tuned mass dampers (AMTMD) for translational and torsional response control of a simplified two-degree-of-freedom (2DOF) structure, able to represent the dynamic characteristics of general asymmetric structures, under the ground acceleration. This 2DOF structure is a generalized 2DOF system of an asymmetric structure with predominant translational and torsional responses under earthquake excitations using the mode reduced-order method. Depending on the ratio of the torsional to the translational eigenfrequency, i.e. the torsional to translational frequency ratio (TTFR), of asymmetric structures, the following three cases can be distinguished: (1) torsionally flexible structures (TTFR < 1.0), (2) torsionally intermediate stiff structures (TTFR = 1.0), and (3) torsionally stiff structures (TTFR > 1.0). The even distribution of the AMTMD within the whole width and half width of the asymmetric structure, thus leading to three cases of installing the AMTMD (referred to as the AMTMD of case 1, AMTMD of case 2, AMTMD of case 3, respectively), is taken into account. In the present study, the criterion for searching the optimum parameters of the AMTMD is defined as the minimization of the minimum values of the maximum translational and torsional displacement dynamic magnification factors (DMF) of an asymmetric structure with the AMTMD. The criterion used for assessing the effectiveness of the AMTMD is selected as the ratio of the minimization of the minimum values of the maximum translational and torsional displacement DMF of the asymmetric structure with the AMTMD to the maximum translational and torsional displacement DMF of the asymmetric structure without the AMTMD. By resorting to these two criteria, a careful examination of the effects of the normalized eccentricity ratio (NER) on the effectiveness and robustness of the AMTMD are carried out in the mitigation of both the translational and torsional responses of the asymmetric structure. Likewise, the effectiveness of a single ATMD with the optimum positions is presented and compared with that of the AMTMD.

• Structural Engineering and Mechanics
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• 제63권5호
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• pp.617-628
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• 2017

In order to study the failure mode and seismic behavior of the interior-joint in steel traditional-style buildings, a single beam-column joint and a double beam-column joint were produced according to the relevant building criterion of ancient architectural buildings and the engineering instances, and the dynamic horizontal loading test was conducted by controlling the displacement of the column top and the peak acceleration of the actuator. The failure process of the specimens was observed, the bearing capacity, ductility, energy dissipation capacity, strength and stiffness degradation of the specimens were analyzed by the load-displacement hysteresis curve and backbone curve. The results show that the beam end plastic hinge area deformed obviously during the loading process, and tearing fracture of the base metal at top and bottom flange of beam occurred. The hysteresis curves of the specimens are both spindle-shaped and plump. The ultimate loads of the single beam-column joint and double beam-column joint are 48.65 kN and 70.60 kN respectively, and the equivalent viscous damping coefficients are more than 0.2 when destroyed, which shows the two specimens have great energy dissipation capacity. In addition, the stiffness, bearing capacity and energy dissipation capacity of the double beam-column joint are significantly better than that of the single beam-column joint. The ductility coefficients of the single beam-column joint and double beam-column joint are 1.81 and 1.92, respectively. The cracks grow fast when subjected to dynamic loading, and the strength and stiffness degradation is also degenerated quickly.

• 한국지진공학회논문집
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• 제25권3호
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• pp.111-119
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• 2021

A shear wall is a structural member designed to effectively resist in-plane lateral forces, such as strong winds and earthquakes. Due to its efficiency and stability, shear walls are often installed in residential buildings and essential facilities such as nuclear power plants. In this research, to predict the results of the shaking table test of the three-story shear wall RC structure hosted by the Korea Atomic Energy Research Institute, three types of numerical modeling techniques are proposed: Preliminary, Calibrated 1, and Calibrated 2 models, in order of improvement. For the proposed models, an earthquake of the 2016 Gyeongju, South Korea (peak ground acceleration of 0.28 g) and its amplified earthquake (peak ground acceleration of 0.50 g) are input. The response spectra of the measuring points are obtained by numerical analysis. Good agreement is observed in the comparisons between the experiment results and the simulation conducted on the finally adopted numerical model, Calibrated 2. In the process of improving the model, this paper investigates the influences of the mode shape, material properties, and boundary conditions on the structure's seismic behavior.

• Structural Engineering and Mechanics
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• 제70권6호
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• pp.765-779
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• 2019

Most of the existing evaluation criteria of vibration serviceability rely on the peak acceleration of the structure rather than that of the people keeping their own body unmoved on the structure who is the real receiver of structural vibrations. In order to accurately assess the vibration serviceability, therefore, a full path assessment approach of vibration serviceability based on vibration source, path and receiver is not only tentatively proposed in this paper, taking the peak acceleration of receiver into account, but also introduce a probability procedure to provide more instructive information instead of a single value. In fact, semi-rigid supported on both sides of the structure is more consistent with the actual situation than simply supported or clamped due to the application of the prefabricated footbridge structures. So, the footbridge is regarded as a beam with semi-rigid supported on both sides in this paper. The differential quadrature-integral quadrature coupled method is not only to handle different type of boundary conditions, but also after being further modified via the introduction of an approximation procedure in this work, the time-varying system problem caused by human-structure interaction can be solved well. The analytical results of numerical simulations demonstrate that the modified differential quadrature-integral quadrature coupled method has higher reliability and accuracy compared with the mode superposition method. What's more, both of the two different passive control measures, the tuned mass damper and semi-rigid supported, have good performance for reducing vibrations. Most importantly, semi-rigid supported is easier to achieve the objective of reducing vibration compared with tuned mass damper in design stage of structure.

• Computers and Concrete
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• 제27권5호
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• pp.457-472
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• 2021

Reinforced concrete (RC) buildings in Taiwan have suffered failure from strong earthquakes, which was magnified by the non-ductile detailing frames. Inadequate reinforcement as a consequence of the design philosophy prior to the introduction of current standards resulted in severe damage in the column and beam-column joint (BCJ). This study establishes a finite element analysis (FEA) of the non-ductile detailing RC column, BCJ, and three-story building that was previously tested through a tri-axial shaking table test. The results were then validated to laboratory specimens having the exact same dimensions and properties. FEA simulation integrates the concrete damage plasticity model and the elastic-perfectly plastic model for steel. The load-displacement responses of the column and BCJ specimens obtained from FEA were in a reasonable agreement with the experimental curves. The resulting initial stiffness and maximum base shear were found to be a close approximation to the experimental results. Also, the findings of a dynamic analysis of the three-story building showed that the time-history data of acceleration and displacement correlated well with the shaking table test results. This indicates the FEA implementation can be effectively used to predict the RC frame performance and failure mode under seismic loads.

• 대한기계학회논문집 C: 기술과 교육
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• 제3권2호
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• pp.83-88
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• 2015

농용 트랙터는 일반적인 도로 주행이 아닌 논 또는 밭과 같은 험지에서 작업용으로 사용한다. 때문에 정적 하중 뿐만 아니라 동적 하중이 고려된 구조 해석이 진행되어야 한다. 하지만 동적 입력 하중을 계산하기 위해서는 다양한 작업기와 하중조건을 모사해야 하기에 실제 측정에 많은 시간과 노력이 소요된다. 이러한 노력들을 줄이기 위해서 본 연구에서는 상용 자동차와 동일하게 농용 트랙터를 위한 4 축 도로하중 시뮬레이터(4-Post Road Simulator) 모델을 개발하였다. 입력하중을 검증하기 위해 사내 험로 시험장에서 차축의 가속도 값과 바디프레임의 변형률(strain)을 측정하였다. 가속도 값은 동역학 모델의 입력 하중으로 사용하고 모드 중첩 법을 포함한 동역학 해석을 수행하여 변형률을 검증하였다. 이를 통해 험로 프로파일과 유사한 거동을 나타내는 4 축 도로하중을 구할 수 있었으며 신뢰성을 검증하였다.

• 한국항공우주학회지
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• 제50권8호
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• pp.531-540
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• 2022

본 논문에서는 IMM 필터 기반으로 장사정포의 탄종을 식별하고 탄착점을 신속하게 예측하는 알고리즘을 제시한다. 탄도궤적 방정식을 시스템 모델로 사용하고, 각각 다른 탄도계수 값을 갖는 3가지 모델을 IMM 필터에 적용한다. 가속도를 중력, 공기저항, 양력에 의한 3가지 성분으로 나누고 양력가속도를 새로운 상태변수로 추가하여 추정한다. 속도벡터와 양력가속도가 수직이라는 운동학 조건을 유사 측정값으로 추가한 측정방정식을 다룬다. IMM 필터를 통해 추정된 상태변수와 모드 확률이 가장 높은 모델의 탄도계수를 기반으로 탄착점을 예측한다. 탄착점 예측을 위해 일반적으로 사용되는 룽게-쿠타 수치적분 대신, 준해석적인 방법을 사용하여 적은 계산량으로 탄착점을 예측할 수 있음을 설명한다. 마지막으로 최소제곱법을 이용한 상태변수 초기화 방법에 대해 제안하고 성능을 확인하였다. 탄종식별, 탄착점 예측 및 초기화를 포함한 통합 알고리즘을 제시하고 시뮬레이션을 통해 제안한 방법의 타당성을 검증하였다.