• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 제4회 압출 및 인발가공 심포지엄
• /
• pp.99-106
• /
• 2001

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die Insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.

• 한국정밀공학회지
• /
• 제22권1호
• /
• pp.167-174
• /
• 2005

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.

• 한국철도학회논문집
• /
• 제6권4호
• /
• pp.246-251
• /
• 2003

A quantitative analysis on the amounts of cant and lateral displacement of gravitational center due to the introduction of high-speed tilting car was carried out, based on the current alignment of the conventional line. In addition, the maximum allowable speed in curve and the level of improvement in maximum speed of tilting car were evaluated through the comparison with the maximum speed of locomotive. It was found that the tilting car produces an equivalent amount of cant, which corresponds to 47.5 % of current actual cant. This effect could be explained by the fact that 1.34 m, which is the height of gravitational center of tilting car from the rail level, is much lower than that of locomotive and thus guarantees much higher level of safety in curve. The equivalent amount of cant due to the lateral displacement of gravitational center followed by tilting in curve was 2.4 mm. It was small but not enough to be neglected and must be included in calculating the maximum speed in curve. It could be concluded that the 15 % speed-up of the conventional line is reasonable under the current condition of alignment.

• 한국농공학회논문집
• /
• 제60권1호
• /
• pp.59-65
• /
• 2018

The object of this paper was to analyze combined load acting on agricultural reservoir. This study was carried out to 3-D numerical modeling for displacement characteristic and seismic acceleration characteristic. The results of study were analyzed and summarized as follow. It was found that the displacement caused by combined load acting on railway and agricultural reservoir did not reflect the effect of load and the seismic wave consistently. The ground accelerations that occur in railway and dam were amplified because 3-D numerical analysis program interprets ground as an elastic body. Actual ground shows characteristics of elasticity and plasticity, so measured values will show different tendency. As a result of analyzing displacement characteristics, it is considered to be related to stiffness. The Ofunato seismic wave, the displacement (77.1 mm) of the body satisfied the allowable displacement (220 mm), but The Hachinohe seismic wave (282.8 mm) did not. It is considered that displacement caused by combined load is affected not only by acceleration but also by characteristics of materials.

• 한국공작기계학회논문집
• /
• 제17권2호
• /
• pp.90-96
• /
• 2008

A pneumatic system was proposed to evaluate displacement accuracy of the pneumatic actuator without external load and to analyze capability of integration of the proposed valve system. The proposed pneumatic system consisted of a combination of pneumatic valves, two proximity sensors, and a programmable logic controller(PLC). The position controller is based on the PLC controller connected with the proximity sensors. Displacement accuracy of the pneumatic cylinder stroke was tested by varying air pressures of the supply and discharge-side and strokes of the pneumatic cylinder. The displacement accuracy of the pneumatic cylinder stroke increased as the supply and discharge side of air pressure increased at the stroke length of 133mm. Also the displacement accuracy increased as the stroke length increased with a fixed supply and discharge side of air pressure of the pneumatic cylinder as 3.5 and $4.5kg/cm^2$, respectively. The most accurate displacement of the pneumatic cylinder(i.e., standard deviation of 0.01 mm) was obtained at the supply and discharge side of air pressure of 4.0 and $5.0kg/cm^2$, respectively, and strokes of 170 and 190 mm among arbitrarily selected supply and discharge side air pressures and strokes.

• 한국재난정보학회 논문집
• /
• 제17권3호
• /
• pp.454-464
• /
• 2021

연구목적: 기시공되어 현재 운행 중인 2-Arch 터널에 대하여 피난연결통로 신설의 필요성이 대두되고 있다. 이에 본 연구는 중앙벽체 굴착에 따른 터널 및 벽체 거동 분석과 안정성 분석에 목적을 두고 있다. 연구방법: 2-Arch 터널과 피난연결통로의 이론적 배경을 설명하고, 3차원의 유한요소 수치해석을 통하여 터널 및 벽체의 거동을 집중적으로 분석하였다. 다양한 지반 조건을 변수로 하여 암반 등급에 따른 매개변수 해석을 수행하였으며, 중앙벽체의 변위와 응력을 집중적으로 분석하였다. 연구결과: 중앙벽체 굴착 시 개구부 중앙에서 가장 큰 침하량을 보였으며, 응력은 첫 번째 굴착 시 가장 크게 발생하였다. 또한 개구부 양 상단에서 응력집중 현상이 발생함을 알 수 있었으며, 허용응력 개념을 고려한 안정성 검토 결과 허용응력을 초과하는 것으로 나타났다. 결론: 터널의 천단변위는 허용기준치 내로 안정성을 확보하였지만, 발생응력은 허용기준치를 초과하는 것으로 나타나 시공 시 적절한 보강공법을 적용하여 갑작스런 응력 해방에 대한 방지가 필요할 것으로 사료된다.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2000년도 학술발표회 발표논문집
• /
• pp.438-443
• /
• 2000

A wide range of problems geotechnical engineering have been analyzed by using the finite element method. In order to establish confidence in a numerical procedure, it is desirable that numerical solution be verified against field or laboratory observations, or both, and in order to aid the user in applying the method to practical problems, it is necessary to examine effects of various parameters that influence the behavior of engineering structures. Often it can be profitable to translate numerical solutions in formats that can be used readily for design analysis. The allowable bearing capacity of concrete piles is mainly governed by settlement rather than by strength of soil. Therefore, the load-displacement behavior of piles should be well understood at the design stage. This paper deals with some of these goals by considering the problem of load-displacement behavior of axially-loaded pile foundations.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 말뚝기초 학술발표회
• /
• pp.65-84
• /
• 2000

Europe and US which have more restrictive regulations than Korea about the noise and vibration during construction are using Auger-cast Pile to reduce the problem relating with noise and vibration. However Auger-cast Pile has problems like difficult quality control and low bearing capacity. In Europe, Displacement in-situ concrete Pile has been used to sove that problems since 1990s, and Korea has performed the test construction in 1997 and it has been used as the real structural foundation since 1998. Test and real construction results verified that the allowable capacity of the pile(diameter = 410mm) is between 70 and 100ton. Though De Beer & Van Imps design method utilizing CPT result is used to calculate the bearing capacity of the Displacement in-situ Pile, Korea is dependant upon the SPT as the sounding test, so design method utilizing SPT result is necessary to promote the application of the pile. To find out reasonable design method using SPT result, rearing capacity of the pile constructed in sand and clay in Korea was calculated using Meyerhof, SPT-CPT translation method, Nordlund, Douglas and DM-7 method, and the calculation results were compared to the load test result. Analysis result shows that SPT-CPT translation method is more reliable than others and economical design can be possible because it considers efficiently the friction capacity of Displacement in-situ Pile.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
• /
• pp.472-485
• /
• 2008

In this study, sand compaction pile method was adopted to improve the soft ground under the permanent dyke, namely west sea dyke of Incheon New Port. The row replacement ratio 30% was applied to consider the ground condition, environmental side and the construction cost of the site. The stability and displacement analysis was carried out by respectively SLOPE/W and PLAXIS 2D program. Based on this analysis, it is found that the safety factor and displacement is within an allowable criteria. The model experiment was carried out using the acryl soil box with $400(H){\times}1200(L){\times}250(W)mm$ to show the displacement of the dyke and behavior of soft ground. Based on this experiment results, it is found that the settlement does not occur from 1 and 2 loading phases and horizontal displacement of 0.0075% occurs from 2 phases. It is also found that the differential settlement occurs 0.05mm corresponding respectively 0.02% and 0.03% of the dyke height(15cm).

• 한국군사과학기술학회지
• /
• 제24권5호
• /
• pp.545-557
• /
• 2021

Engine is the main source of vibration that generates unwanted noise and vibration of vehicle chassis. Especially, in submarine applications, radiation of noise signatures can be detected at some distance away from the submarine using a sonar array. Thus quiet operation is crucial for submarine's survivability. This study addresses reduction of the force transmissibility originating from engines and transmitted to hull through engine mounts. An inertial damper, as an actuator of hybrid mount system, is addressed to reduce even further the level of vibration. Narrow band FxLMS algorithms are broadly used to cancel the vibration of engine mount because of its excellent performance of canceling narrow band noise. However, in real active dampers, the maximum displacement of damper mass is kinematically restricted. When the control input signal from the FxLMS algorithm exceeds this limitation, the damper mass will collide with the mechanical stops and results in many problems. Originated from these, a modified narrow band FxLMS algorithm based on the equalizer technique with the maximum allowable displacement of active damper mass is proposed in this study. Some simulation results showed that the propose algorithm is effective to suppress vibration of engine mount while ensuring given displacement constraint.