• 한국멀티미디어학회논문지
• /
• 제14권1호
• /
• pp.133-143
• /
• 2011

본 연구에서는 햅틱 정보를 이용하여 시각장애인들이 이동할 방향을 촉각적으로 제시할 수 있는 휴대용 네비게이션 시스템을 제안한다. 시각장애인들에게 촉각정보를 전달하기 위해 솔레노이드, 영구자석 및 탄생 스프링으로 이루어진 촉감 모듈을 개발하고 제안하는 시스템에 탑재한다. 또한 진동모터를 탑재하여 제안한 시스템의 특정 지역에서 진동이 발생하여 시스템의 표면을 타고 다른 곳으로 흘러가는 2D 이동진동과 기법을 제안한다. 촉감모듈과 이동진동파는 제안하는 시스템 내에서 사람의 손가락과 손바닥을 각각 촉각적으로 자극함으로 방향을 제시한다. 제안한 시스템이 촉각적으로 사용자에게 방향성을 제시할 수 있는가를 증명하기 위하여 실험을 수행한다. 본 연구의 실험 결과로부터 제안하는 시스템은 사용자에게 실시간으로 이동할 방향을 전달함을 알 수 있다.

• International Journal of Concrete Structures and Materials
• /
• 제10권3호
• /
• pp.297-306
• /
• 2016

This paper developed an analytical software, called Simulation of Concrete Structures (SCS), which is used for numerical analysis of shear-critical prestressed steel fiber concrete structures. Based on the previous research at the University of Houston (UH), SCS has been derived from an object-oriented software framework called Open System for Earthquake Engineering Simulation (OpenSees). OpenSees was originally developed at the University of California, Berkeley. New module has been created for steel fiber concrete under prestress based on the constitutive relationships of this material developed at UH. This new material module has been integrated with the existing material modules in OpenSees. SCS thus developed has been used for predicting the behavior of the prestressed steel fiber concrete I-beams and Box-beams tested earlier in this research. The analysis could well predict the entire behavior of the beams including the elastic stiffness, yield point, post-yield stiffness, and maximum load for both web shear and flexure shear failure modes.

• 소성∙가공
• /
• 제18권3호
• /
• pp.210-216
• /
• 2009

Springback, an elastic material recovery after the unloading of stamping tools, causes variations and inconsistencies of final part dimensions. Recently, narrow and long surround molding parts around door frame are applied to high grade automobiles, but there are great difficulties in their die development, construction and tryout because of several springback modes including vertical movement and twist during flange forming process of them. So it is very important to predict springback's quantities of a surround molding part and, moreover, to compensate the die for them adequately, when they can't be corrected by the restrike operation. This paper presents a case study based on the die design for a surround molding part made of stainless steel. The forming and springback predictions, carried out using PAMSTAMP 2G, are reported and compared with the measurement data of the prototype. The predicted springback results were acceptable, so the processes of compensating die using Automatic Die Compensation Module of PAMSTAMP 2G were performed iteratively until the tolerances between the designed shape and the simulation data were satisfied.

• 한국자동차공학회논문집
• /
• 제18권4호
• /
• pp.1-7
• /
• 2010

Large quantity of bending deformation as well as irregular rotating torque fluctuation are the main struggles of the balance shaft module during a high speed rotation. Since two issues are much sensitive to the location of both supporting bearing and unbalance mass at a balance shaft, it is recommended to construct a design strategy on balance shaft at the early stage so as to save developing time and effort before approaches to the detailed design process. In this paper, an optimal design formulation is proposed to minimize the elastic strain energy due to bending as well as the kinematic energy of polar moment of inertia in rotation. Case studies of optimal design are conducted for different mass ratio as well as linear combination of objective function and its consequence reveals that global optimum of balance shaft model is existed over possible design conditions. Simulation shows that best locations of both supporting bearing and unbalance are globally 20% and 80%, respectively, over total length of a balance shaft.

• 대한기계학회논문집A
• /
• 제38권2호
• /
• pp.115-120
• /
• 2014

본 연구에서는 다물체 동역학 해석 소프트웨어인 RecurDyn 을 이용하여 풍력 발전기를 쉽게 모델링하고 동적 거동 해석을 수행할 수 있는 기법을 개발하였다. 풍력 발전기는 타워, 너셀, 허브, 그리고 블레이드로 구성되어 있다. 타워와 블레이드는 탄성체로 가정하였고 탄성효과를 고려하기 위하여 탄성체 이론을 이용하여 모델링 하였다. 바람의 속도는 일정하다고 가정하였고 날개 요소 운동량 이론을 이용하여 공력하중을 모델링 하였다. 이를 통해 계산된 공력을 풍력 발전기에 적용시키고 동적 거동 해석을 수행하였다. 해석의 타당성을 검증하기 위하여 풍력 발전 시스템 상용 소프트웨어인 GH-Bladed를 이용한 해석결과와 비교하였다.

• Journal of Advanced Research in Ocean Engineering
• /
• 제4권1호
• /
• pp.25-34
• /
• 2018

In this study, the behavior of the coupled mooring system and floating body is analyzed. The related works are introduced for the mooring analysis of the floating body. Equations motion are introduced for calculating mooring force connected with the floating body. For formulating the equations of motion, the concept of the constrained force is applied for compact expression of it. The input and output data of the module for calculating mooring force is defined. The static analysis and quasi-static analysis are performed. For the analysis, equilibrium equation for elastic catenary mooring line is used by employing finite element method, and the C# solver is developed in this research. The analysis results are validated by comparing with other research results.

• Computers and Concrete
• /
• 제19권1호
• /
• pp.33-39
• /
• 2017

In this study, two types of aggregate were used for making self-compacting concrete. Standard cubic specimens were exposed to different temperatures. Seventy-two standard cylindrical specimens ($150{\times}300mm$) and Seventy-two cubic specimens (150 mm) were tested. Compressive strengths of the manufactured specimens at $23^{\circ}C$ were about 33 MPa to 40 MPa. The variable parameters among the self-compacting concrete specimens were of sand stone type. The specimens were exposed to 23, 100, 200, 400, 600, and $800^{\circ}C$ and their mechanical specifications were controlled. The heated specimens were subjected to the unconfined compression test with a quasi-static loading rate. The corresponding stress-strain curves and modulus of elasticity were compared. The results showed that, at higher temperatures, Scoria aggregate showed less sensitivity than ordinary aggregate. The concrete made with Scoria aggregate exhibited less strain. The heated self-compacting concrete had similar slopes before and after the peak. In fact, increasing heat produced gradual symmetrical stress-strain diagram span.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 A
• /
• pp.121-123
• /
• 1999

The purpose of this paper is to establish a method of design of the Ultrasonic Motor for Driving Robot Hand. This method is based on two models for the ultrasonic motor(a two dimensional elastic contact model. electric equivalent circuit). And analyzed the basic model which installed in the module to match the suitable standard. As varied external diameter, internal diameter and thickness, the proper ultrasonic motor is implemented to find a targeted resonant-frequency and torque near to designed values.

• 대한치과교정학회지
• /
• 제18권1호
• /
• pp.55-63
• /
• 1988

It has been suggested that the frictional force between bracket and arch wire may impede the tooth movement. The present study was aimed to compare and analyze the effect of wire size, type of ligation, and duration of ligation on the magnitude of frictional force between cobalt chromium wire and stainless steel bracket under the artificial saliva. The results were as follows: 1. Type of ligation and size of wire were the main influencing factor on the level of friction. 2. Stainless steel ligature generated higher frictional forces than elastomeric module. 3. The rectangular wire consistently exhibited more frictional force values than round wires, while there was no significant difference between frictional forces of round wires. 4. In elastic ligature, frictional force decreased with time. 5. Artificial saliva had no significant influence on the frictional force between cobalt chromium wire and bracket.

• 한국안전학회지
• /
• 제16권2호
• /
• pp.91-96
• /
• 2001

Theoretical definitions of mixed behavior of PE panel and connote should have preceded to cause a mixed behavior of connote and polyethylene which have different elastic module, one-line expansion coefficients, poison ratios, compressive strengths and tensile strengths. Consequently, changes are analyzed through experiment process to identify the effects on interpretation of mixed behavior on the basis of temperature change of structures, temperature rise of concrete other than PE panel due to hydration heat temperature rise of concrete other than PE panel due to drying and contraction, working of hydrostatic pressure by storage and temperature gradient From the results of interpretation of the analysis, it is concluded that PE panel have slight influences on the change of guess of structures and maintains structural stability compared with concrete structures without PE panel.