• Structural Engineering and Mechanics
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• 제82권4호
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• pp.503-515
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• 2022

The multi-rigid-body matrix method (MRBMM) is a generalized modeling method for obtaining the displacements, forces, and dynamic characteristics of a compliant mechanism without performing inner-force analysis. The method discretizes a compliant mechanism of any type into flexure hinges and rigid bodies by implementing a multi-body mass-spring model using coordinate transformations in a matrix form. However, in this method, the deformations of bodies that are assumed to be rigid are inherently omitted. Consequently, it may yield erroneous results in certain mechanisms. In this paper, we present a multi-compliant-body matrix-method (MCBMM) that considers a rigid body as a compliant element, while retaining the generalized framework of the MRBMM. In the MCBMM, a rigid body in the MRBMM is segmented into a certain number of body nodes and flexure hinges. The proposed method was verified using two examples: the first (an XY positioning stage) demonstrated that the MCBMM outperforms the MRBMM in estimating the static deformation and dynamic mode. In the second example (a bridge-type displacement amplification mechanism), the MCBMM estimated the displacement amplification ratio more accurately than several previously proposed modeling methods.

• 로봇학회논문지
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• 제17권2호
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• pp.209-215
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• 2022

In this paper, a forearm Mechanism design inspired by ligamentous structure of the human body is proposed. The proposed mechanism consists of four rigid bodies and fourteen wires without any mechanical joints. Actually, the mechanism is based on the concept of the tensegrity structure. Therefore, the proposed mechanism has inherently compliant characteristics due to the flexibility of the wires composing the structure. Rigid bodies and wires of the mechanism mimic bones and major ligaments in the forearm of the human. The proposed mechanism is classified as one of the interconnected hybrid flexure systems. The analysis method of the degree of freedom (DOF) of the proposed mechanism is also introduced through analyzing technique of the interconnected hybrid flexure systems, in this paper. Ultimately, the proposed mechanism, whose structure is complicated with rigid bodies and wires, mathematically drives that it has 3-DOFs.

• 대한기계학회논문집
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• 제19권9호
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• pp.2165-2172
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• 1995

Optimization of mesh discretization has been proposed to improve the accuracy of limit analysis solution of collapse load by using the Rigid Body Spring Model(R. B. S. M) under the plane strain condition. Moreover, the fracture behaviour of materials was investigated by employing the fracture mechanism of a spring connecting the triangular rigid body element. It has been clarified that the collapse load and the geometry of slip boundary for optimized mesh discretization were close to those of the slip line solution. Further, the wedge-shaped fracture of a cylinder under a lateral load and the central fracture of a strip in the drawing process were well simulated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1699-1703
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• 2000

While the booming occurs in a cabin, the powertrain and subframes which are the main sources and paths of the booming, show the rigid body motions. This paper presents a technique to predict the booming noise in a car using the rigid body information of the important parts. The rigid body information comes from the CAD data, from which we can predict the response of the complex system. Since the mechanism of this technique is very similar to the finite element formulation, we can apply it to the complex system with ease.

• 한국생산제조학회지
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• 제21권1호
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• pp.182-189
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• 2012

This study suggests a dynamic design process for deciding properly design parameters of a mass-spring type Wave Energy Converter (WEC) to achieve sufficient energy conversion from wave to power generator. The WEC mechanism, in this research, consists of a rigid sprung body, a platform, suspension springs and dampers. The rigid sprung body is supported on the platform via springs and dampers and vibrates translationally in the heave direction under wave excitation. At last the resulting heave motion of the sprung body is transmitted to rotating motion of the electric generator by rack and pinion, and transmission gears. For the purpose of vibration analysis, the WEC mechanism has been simply modelled as a mass-spring-damper system under harmonic base excitation. Its maximum displacement transmissibility and steady state response can be determined by using elementary vibration theory if the harmonic ocean wave data were provided. With the vibration analysis results, the suggested dynamic design process of WEC can determine all the design parameters of the WEC mechanism, such as sprung body mass, suspension spring constant, and damping coefficient that can give sufficient relative displacement transmissibility and the associated inertia moment to drive the electric generator and transmission gears.

• 대한기계학회논문집A
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• 제36권7호
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• pp.745-750
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• 2012

이 논문에서는 강체 메커니즘의 위상 최적설계를 위해 제안된 구속조건 힘 설계 기법(constraint force design method)을 확장하여 로프-링크(string-link)를 고려한 위상 최적설계기법을 제안한다. 기존의 메커니즘 설계이론을 이용하여 메커니즘을 구성하는 강체 링크의 길이와 조인트의 위치를 최적설계하는 것은 가능하다. 하지만 강체 메커니즘의 최적 위상을 설계하는 것은 어렵다는 것으로 알려져 있다. 강체 메커니즘의 최적 위상을 설계할 수 있는 기법인 구속조건 힘 설계 기법이 본 연구자들에 의해 제안되었다. 구속조건 힘 설계 기법은 이진수 설계 변수를 이용하여 강체 링크의 위상 최적설계를 가능하게 한다. 이번 연구에서는 강체 링크뿐만 아니라 로프-링크로 구성된 메커니즘을 위상 최적설계하기 위한 발전된 해석기법과 설계 기법을 제안한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 춘계학술대회 논문집
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• pp.113-118
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• 1997

This paper presents the dimensional synthesis and kinematic analysis of the RSCS-SSP motion generating spatial mechanism using the displacement matrix method. This type of spatial mechani는 is used for the Mcpherson suspension in small automobiles. It is modeled for the wheel bump/rebound and steering motion. First, the suspension is modeled as a multiloop spatial rigid body guidance mechanism for the two major motions. Then the design equations for SSP, RS, and SC strut links are applied to synthesize an RSCS-SSP for up to three prescribed positions for the steering motiom from the suspension design specification. Thus a RSCS-SSP mechanism which is synthesized is also analyzed for the displacement during the steering motion.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.464-466
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• 2014

The mechanism synthesis methods, graphical, analytical and computer-aided technique have been proposed for selecting and scaling mechanical system. According to developing computation tools, mechanism could be synthesized much faster and more correct than previous analytical ways by improved techniques. In this paper, the improved synthesis method is proposed to solve body guidance synthesis problem. To perform the mechanism synthesis for body guidance, a planar linkage is modeled as a set of free three bushings located in design space. The values of bushing stiffness and x, y position of bushings yielding a desired functional requirement related to input motion are found by using an optimization technique.

• 한국지반신소재학회논문집
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• 제5권3호
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• pp.1-7
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• 2006

1960년대 초 오스트리아에서 개발된 그린월(green wall) 공법은 독립식 콘크리트 보형식의 옹벽으로, 전, 후면 가로보와 세로방향으로 버팀보를 연속적으로 쌓아 올려 내부에 다짐성토를 시행, 구조체가 일체 거동하도록 강성벽체(rigid body)를 형성시키는 옹벽 구조물이다. 국내의 경우, 옹벽 전면 가로보 사이의 공간에 식생이 가능한 친환경적 장점이 있어, 1999년 이후 국내실정을 고려 원지반의 토공량을 최소화할 수 있도록, 쏘일네일 등으로 보강하여 절토 공사현장에 다양하게 적용되고 있는 추세이다. 그러나 그린월 옹벽과 배면에 보강된 쏘일네일이 합벽시공될 경우, 네일에서의 토압분담효과 등에 대한 영향을 고려하지 않고 일반적인 Rankine 토압으로 설계, 시공하여 이중으로 보강공사비용이 투입되고 있는 실정이다. 따라서 본 연구에서는 G$\ddot{a}$ssler(1988)가 제안한 'Two-Body Translation Mechanism(TBTM)'을 이용한 안정해석기법을 수정하여, 네일의 토압 분담효과를 반영할 수 있는 설계기법을 제시하였으며, 본 연구에서 제안한 설계기법을 적용하여 그린월의 보수, 보강공사 비용을 상당부분 감소한 현장설계 사례를 소개하고자 한다. 아울러 본 연구에서 제시한 설계기법을 토대로 계산된 토압을 수치해석 결과와 비교, 검토해 보았다.

• 한국정밀공학회지
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• 제27권3호
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• pp.89-94
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• 2010

The pretensioner is used to retract the belt webbing and tighten up any slack in the event of a crash. The retracting force of the pretensioner helps move the passenger into the optimum crash position in his or her seat. In this paper, the new concept of an operating mechanism of the pretensioning system is presented. The internal gear design program is developed using MATLAB. Two kinds of numerical analysis model are created. The first one, the rigid body dynamic model, is used to estimate the performance of several gear pairs. The initial performance of the new operating mechanism is analyzed and the best combination of the gear pairs is selected. The second one, the structural dynamic model, is used to calculate the deformation of the gear teeth. To decrease the deformation and interference of the teeth, the shape of the gear pairs is changed.