• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.367-368
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• 2012

In resent years, engineering thermoplastics represent a means for designers to integrate parts, facilitate assembly, reduce weight and lower the costs of their parts to improve the fuel efficiency and competitiveness of the cars. Thermoplastic turbo charger intake hose is one of most sophisticated application in thermoplastics under the hood. Used as part of weight & cost reduction and performance improvement program, thermoplastic turbo charger intake hose has been developed as rubber and metal replacement. For optimized product, NVH performance is a important criteria while keeping same durability required with current system. Though a number of studies have been conducted on the resonator hose and its analytical models, the most of studies were focused on transmission loss itself. This paper presents contribution of vehicle interior noise according to design parameters like profile, bellows type, bellows position, material characteristic. And we will review the design guidance for optimized product of thermoplastic turbo charger intake hose.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.595-601
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• 2003

For monitoring of the civil and building structure, optical fiber sensors are very convenient. The fiber sensors are very small and do not disturb the structural properties. They also have several merits such as electro-magnetic immunity, long signal transmission, good accuracy and multiplicity of one sensor line. Strain measurement technologies with fiber optic sensors have been investigated as a part of smart structure. In this paper, we investigated the possibilities of fiber optic sensor application to the monitoring of beam-column joints of structures. We expect that the fiber optic sensors replace electrical strain gauges. The commercial electric strain gauges show good stability und dominate tile strain measurement market. However, they lack durability and long term stability for continuous monitoring of the structures. In order to apply the strain gauges, we only have to attach them to the surfaces of the structures. In this paper, we investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show nice response to the structural behavior of the joint.

• 한국정밀공학회지
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• 제33권8호
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• pp.623-628
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• 2016

This article describes the determination of the dynamic stability for a heavy press, particularly considering rotational speed. A finite element model of the driving parts for the heavy press was generated. We also applied boundary conditions and dynamic loads considering the driving conditions. Modal analysis was conducted using the finite element construction model. Therefore, no resonance was identified with the comparison between the results of the modal analysis and vibration excitation frequency by the gear tooth. In addition, the stress distribution of the driving parts for press was determined using transient analysis. As compared to the yield strength of the material, the dynamic stability the heavy press was confirmed.

• 한국소음진동공학회논문집
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• 제26권6_spc호
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• pp.660-666
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• 2016

This paper presents performance comparison results of magneto-rheological (MR) brake in the sense of wear characteristics. To create wear circumstance, the brake is operated in 100 000 cycles by DC motor. To make wear test in same design parameters such as the radius of the housing, ferromagnetic disc and gap size, small sample of stainless are inserted in housing of MR brake. The performances of brake are compared between the initial stage (no wear) and 100 000 revolution cycles operated stage (wear). At each circumstance, torque of the brake is measured and compared by applying step current and sinusoidal control input. The controller used in this work is a simple, but effective PID controller. It is demonstrated that the wear behavior is more obvious as the operating cycle is increased in the torque control process.

• 드라이브 ㆍ 컨트롤
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• 제16권2호
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• pp.43-50
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• 2019

The objective of this study was to reverse engineer a swash plate type piston pump mounted on a wheeled armored vehicle and to analyze the structure of the pump case. From the analysis, the weak parts were identified and corrected in the final design. Each element corresponding to the piston pump case was analyzed. The analytical method was given static boundary conditions, load conditions and confirmed displacement, strain, stress, and safety factor. Plastic deformation and damage were also confirmed and the component elements redesigned through structural analysis Structural analysis and vibration analysis were carried out for the components of the piston pump case. The piston pump model was finally modified by structural analysis and vibration analysis results for each component assembly, and a prototype was designed. Durability test and environmental test were carried out and the test results satisfied all of the requirements. Therefore, the analytical method presented in this study can be utilized as a methodology for element component design in the development of various piston pumps.

• Smart Structures and Systems
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• 제23권6호
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• pp.669-682
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• 2019

Vibration mitigation of cables or hangers is one of the crucial problems for cable supported bridges. Previous research focused on the behaviors of cable with dampers or crossties, which could help engineering community apply these mitigation devices more efficiently. However, less studies are available for hybrid applied cross-ties and dampers, especially lack of both analytical and experimental verifications. This paper studied damping and frequency of two parallel identical cables with a connection cross-tie and an attached damper. The characteristic equation of system was derived based on transfer matrix method. The complex characteristic equation was numerically solved to find the solutions. Effects of non-dimensional spring stiffness and location on the maximum cable damping, the corresponding optimum damper constant and the corresponding frequency of lower vibration mode were further addressed. System with twin small-scale cables with a cross-link and a viscous damper were tested. The damping and frequency from the test were very close to the analytical ones. The two branches of solutions: in-phase modes and the out-of-phase modes, were identified; and the two branches of solutions were different for damping and frequency behaviors.

• 한국전자통신학회논문지
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• 제15권6호
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• pp.1175-1186
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• 2020

본 논문은 전력발전용 가스터빈에 사용하는 내구성이 개선된 Exhaust Gas Temperature(EGT)센서에 관한 연구이다. 가스 터빈에 적용된 EGT 센서는 고온으로 인하여 EGT 센서의 커넥터가 손상되는 문제가 있고 회전 날개의 회전으로 인해 발생하는 심각한 진동 조건에서 센서의 물리적으로 약한 부분이 진동으로 인하여 손상이 야기되기도 한다. 이러한 문제들은 잦은 센서 교체를 유발하고, 발전 효율을 감소시킨다. 본 논문에서는 이러한 문제점들을 분석하고 개선방법을 제시하였고, 제안된 EGT 센서의 성능을 평가하기 위해서, 고온과 진동조건을 동시에 시험할 수 있는 복합 환경 테스트 장비를 개발하였다. EGT센서의 정확도와 응답시간을 평가하고 열과 진동의 복합환경 시험 장비로 비교시험한 결과 기존 센서는 탄화문제가 발생하였지만, 제안된 센서는 이러한 문제가 해결된 것을 확인하였다.

• 한국산업융합학회 논문집
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• 제24권4_2호
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• pp.475-480
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• 2021

The purpose of this study is to obtain the natural frequency of fuel supply pipes for vehicle engines through modal analysis and testing and compare the resulting values to ensure the reliability of the analysis. In other words, in this study, we obtain the unique frequency of the fuel pipe of the vehicle engine through analysis and testing and compare its results. Comparing the natural frequency obtained through analysis and testing, the first and third vibration modes obtained accurate natural frequency results of less than 1% and very similar results of less than 5% maximum error over the fourth vibration modes. These results are determined that if design changes of fuel pipes are made depending on the vehicle in the future, there will be no problem in obtaining the natural frequency of pipes that have been changed by analysis. Through future analysis and testing, durability and stability evaluation of connections of fuel supply pipes for vehicle engines will be carried out.

• Design & Manufacturing
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• 제16권3호
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• pp.22-27
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• 2022

The demand for new processing technology that can improve productivity is increasing in industries that require large-scale and various products. In response to this demand, a robot machining system with flexibility is required. Because of the low rigidity of the robot, the robot machining system has a large error during machining and is vulnerable to vibration generated during machining. Vibration generated during machining deteriorates machining quality and reduces the durability of the machine. To solve this problem, a stage for fixing the spindle during machining is required. In order to compensate for the robot's low rigidity, a system combining a piezoelectric actuator for generating a large force and a guide mechanism to actuate with a desired direction is required. Since the rigidity of flexible hinges varies depending on the structure, it is important to optimal design the flexible hinge and high-rigidity system. The purpose of this research is to make analytic model and optimize a flexible hinge and to design a high rigidity stage. In this research, to design a flexible hinge stage, a concept design of system for high rigidity and flexure hinge modeling is carried out. Based on analytic modeling, the optimal design for the purpose of high rigidity is finished and the optimal design results is used to check the error between the modeling and actual simulation results.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4030-4048
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• 2022

In this study, road transportation tests were conducted with surrogate fuel assemblies under normal conditions of transport to evaluate the vibration and shock load characteristics of spent nuclear fuel (SNF). The overall test data analysis was conducted based on the measured acceleration and strain data obtained from the speed bump, lane-change, deceleration, obstacle avoidance, and circular tests. Furthermore, representative shock response spectrums and power spectral densities of each test mode were acquired. Amplification or attenuation characteristics were investigated according to the load transfer path. The load attenuated significantly as it transferred from the trailer to the cask. By contrast, the load amplified as it transferred from the cask to the surrogate SNF assembly. The fuel loading location on the cask disk assembly did not exhibit a significant influence on the strain measured from the fuel rods. The principal strain was in the vertical direction, and relatively large strain values were obtained in spans with large spacing between spacer grids. The influence of the lateral location of fuel rods was also investigated. The fuel rods located at the side exhibited relatively large strain values than those located at the center. Based on the strain data obtained from the test results, a hypothetical road transportation scenario was established. A fatigue evaluation of the SNF rod was performed based on this scenario. The evaluation results indicate that no fatigue damage occurred on the fuel rods.