• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.282-285
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• 2009

MEMS를 적용한 추진기관용 점화안전장치를 설계하고 제작하였다. MEMS는 일반적인 기계요소 설계 방식을 따라 설계하였다. 제작된 시료에 대한 검사 결과와 설계 데이터를 비교해 본 결과 스프링의 비선형 요소에 의한 영향과 가공오차 등으로 인하여 설계된 성능 값과 근사한 차이를 나타냈다. MEMS가 결합된 점화안전장치의 성능 시험을 실시함으로써 MEMS 적용 가능성을 입증하였다.

• 한국공간구조학회논문집
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• 제5권1호
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• pp.99-105
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• 2005

The pushover analysis is becoming a popular tool for seismic design of building structures. In this paper the state-of-art on static nonlinear analysis of building structures is presented with the emphasis on the effects of analysis parameters; i. e., lateral load patterns, modeling of members, and analysis computer programs. The analysed results may have variation even if a same structure is analysed. This paper is to investigate how large the variation is and what the main causes of the variation are. The difference of analysed results, the resultant variation of lateral story shear force and flexural strength of structural members are discussed. The pushover analysis procedure are routinely used in the seismic design of building structures, but some problems must yet be clarified, such as the effects to evaluate the parameters of analysis on the basis of a lateral load patterns and modeling of members.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.190-194
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• 2001

Because, Piezo-electric transducer(PZT) transform electric energy into mechanical energy, it is a adequate material for positioning control and force control, take excellent properties as actuator with high speed and high performance. Recently, researches of ultra precision positioning using this PZT are advanced in. In this paper, we use a actuator of PZT, design a positioning apparatus with ultra precision position apparatus as hinge structure. Because of this purpose, before, we were confirmed in control properties of ultra precision stage by FEM method.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
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• pp.103-110
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• 2004

The pushover analysis is becoming a popular tool for seismic design of building structures. In this paper the state-of-art on static nonlinear analysis of building structures is presented with the emphasis on the effects of analysis parameters; i. e., lateral load patterns, modeling of members, and analysis computer programs. The analysed results may have variation even if a same structure is analysed. This paper is to investigate how large the variation is and what the main causes of the variation are. The difference of analysed results, the resultant variation of lateral story shear force and flexural strength of structural members are discussed. The pushover analysis procedure are routinely used in the seismic design of building structures, but some problems must yet be clarified, such as the effects to evaluate the parameters of analysis on the basis of a lateral load patterns and modeling of members.

• 한국공작기계학회논문집
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• 제18권2호
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• pp.137-143
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• 2009

This paper presents the fabrication of inchworm motor for high precision actuator system of large displacement and high force. The inchworm motor consists of a extend actuator that provides displacement of tool guide and two clamping actuators which provide the holding force. In order to avoid the PZT fracture, design of pre-load housing was conducted by flexure hinge structure, because PZT actuator has low tensile and shear. To design the pre-load housing and optimize the clamping mechanism, the static and dynamic analysis were conducted by finite element method. From these results, a prototype of the inchworm motor was fabricated and dynamic characteristic with respect to the various frequency was tested. The maximum velocity of the inchworm motor was $41.1{\mu}m/s$ at 16Hz.

• Computers and Concrete
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• 제32권5호
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• pp.527-541
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• 2023

This paper emphasizes the use of CFT columns in frame structures subjected to strong horizontal forces and shows that the efficiency of using CFT columns is increased when the plastic design approach is adopted. Because the plastic design approach is based on redistribution of the force of the internal member, a double node for the rotational degrees of freedom, where the adjacent two rotational degrees of freedom can be connected by a non-dimensional spring element, is designed and implemented into the formulation. In addition, an accompanying criterion is considered in order to make it possible to describe the continuous moment redistribution in members connected to a nodal point up to a complete plastic state. The efficiency of CFT columns is reviewed in comparison with RC columns in terms of the cost and the resistance capacity, as defined by a P-M interaction diagram. Three representative frame structures are considered and the obtained results show that the most efficient and economical design can be expected when the use of CFT columns is considered on the basis of the plastic design, especially when a frame structure is subjected to significant horizontal forces, as in a high-rise building.

• 한국강구조학회 논문집
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• 제22권4호
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• pp.325-334
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• 2010

본 연구에서는 반강접 접합부 배치에 따른 구조물 거동특성을 파악하기 위하여 KBC2005 건축구조설계기준으로 비가새 5층 철골 구조물을 설계하여 모든 접합부를 완전 강접합부과 반강접 접합부로 이상화한 경우 그리고 반강접 접합부를 수직배치 및 수평배치한 경우에 대하여 푸쉬오버 구조해석을 실시하였다. 철골 보 및 기둥의 모멘트-곡률관계는 화이버모델을 이용하여 확인하였으며 반강접 접합부의 모멘트-회전각 관계는 3-매개변수 파워모델을 이용하여 나타내었다. KBC2005 등가정적횡하중을 받는 2차원 구조물에 대한 푸쉬오버 구조해석을 실시하여 지붕충변위, 밑면전단력, 접합부 요구연성도, 소성힌지 발생순서 그리고 초과강도계수, 연성계수, 반응수정계수와 같은 설계계수 등을 확인하였다. 반강접 접합부를 부분적으로 사용하면 모든 접합부에 반강접 접합부를 사용한 골조 보다 큰 강도 및 강성도를 확보 할 수 있었고 모든 접합부에 강접 접합부를 사용한 골조 보다 큰 연성능력을 확보할 수 있었다. 초과강도계수는 기준과 비슷하였지만 반응수정계수는 기준 보다 훨씬 큰 값을 보였다. TSD 접합부는 예제 구조물에서 경제성과 안전성을 확보할 수 있음을 확인할 수 있었다.

• 한국전산구조공학회논문집
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• 제30권5호
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• pp.397-404
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• 2017

본 연구의 목적은 트러스의 형태를 바꿔가며 엇갈린 트러스(STF) 시스템의 내진성능을 평가하는 것이다. 예제 구조물은 10층의 철골조 사무실 건물이며, 시스템별로 각각 프랫트러스, 하우트러스, 와렌트러스, 케이트러스와 비렌딜트러스를 적용하였다. 중력하중, 풍하중, 지진하중을 고려한 구조해석을 실시하여 부재에 높은 DCR을 만족하는 단면을 산정한 후 고유주기, 밑면전단력과 층간변위를 산출하였다. 그 후, 역량스펙트럼법을 통해 1.2배의 설계지진(DE)과 최대고려지진(MCE)에 대한 성능점을 산정하고, STF 시스템의 항복여부 및 소성힌지의 분포를 파악하여 구조기준에서 제시한 목표성능수준을 만족하는지 살펴보았다. 평가 결과, 모든 시스템이 해당 목표성능수준을 만족하였으며, 시스템의 경제성 및 효율성을 따져보았을 때, PR10이나 VR10이 가장 적합한 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제86권4호
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• pp.461-472
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• 2023

This paper proposes a novel method for increasing the distortional frame rigidity of off-rail box girder bridges for cranes by reinforcing the diaphragm with staggered truss. The study starts by using the Matrix Displacement Method to determine the shear angle of the staggered truss diaphragm under two assumptions: hinge joint and rigid joint. To obtain closed-form solutions for the transversal and longitudinal deformations and warping stress of the crane girder, the study employs the Initial Parameter Method and considers the compatibility of shear deformation at joints between the diaphragms and the girder. The theoretical solutions are validated through finite element analysis, which also confirms that the hinge-joint assumption accurately represents the shear angle of the staggered truss diaphragm in girder distortion. Additionally, the study conducts extensive parameter analyses to examine the impact of staggered truss dimensions on distortional stress and deformation. Furthermore, the study compares the distortional warping stresses of crane girders reinforced with staggered truss diaphragms and those reinforced with perforated ones, emphasizing the importance of incorporating stagger truss in diaphragms. Overall, this paper provides a thorough evaluation of the proposed approach's effectiveness in enhancing the distortional frame rigidity of off-rail box girder bridges for cranes. The findings offer valuable insights into the design and reinforcement of diaphragms using staggered truss to enhance the structural performance of crane girders.

• 한국군사과학기술학회지
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• 제14권1호
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• pp.132-138
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• 2011

A micromachined silicon accelerometer capable of surviving and detecting very high accelerations(up to 200,000 times the gravitational acceleration) is necessary for a high impact accelerometer for earth-penetration weapons applications. We adopted as a reference model a piezoresistive type silicon micromachined high-shock accelerometer with a bonded hinge structure and performed structural analyses such as stress, modal, and transient dynamic responses and sensor sensitivity simulation for the selected device using piezoresistive-structural coupled-field analysis. In addition, structural optimization was introduced to improve the performances of the accelerometer against the initial design of the reference model. The design objective here was to maximize the sensor sensitivity subject to a set of design constraints on the impact endurance of the structure, dynamic characteristics, the fundamental frequency and the transverse sensitivities by changing the dimensions of the width, sensing beams, and hinges which have significant effects on the performances. Through the optimization, we could increase the sensor sensitivity by more than 70% from the initial value of $0.267{\mu}V/G$ satisfying all the imposed design constraints. The suggested simulation and optimization have been proved very successful to design high impact microaccelerometers and therefore can be easily applied to develop and improve other piezoresistive type sensors and actuators.