These days, the interests on the high speed handling robots are increasing because it is important to get down the unit cost of production to get the price competitiveness. The SCARA robot with simple mechanism is more suitable to implement the high speed robot system as well known. The moving parts of SCARA robot have to be designed for high speed. But the structural analysis is induced by the robot links because they drive in high acceleration and deceleration. In this reason, the structural analysis of the high speed SCARA robot is very important in the design process. In this paper, the study on the structural analysis of a high speed SCARA robot has been done and the research results will be introduced.

SUS hexagonal bar, which is manufactured by drawing process of SUS circular bar, have been widely used to make various adapters and fittings. The purpose of this study is to investigate the characteristics and stability of variable roll unit including stand module. Stand module is essential part of variable roll unit. Structural analysis was performed to predict the stability of stand module using 3 loads (50, 75, 100 Ton), thus it may be of help to the manufacture of stand module. As the results, internal ring of bearing showed maximum equivalent stress, and moreover bearing, shaft and roller had to be preferentially considered in order to maintain its stability. In cases of 50 and 75 Ton, there were no problems for stabilities, respectively, on the other hand, problem for stability may occur in case of 100 Ton.

Flame arrestor as end of line flame arrester for endurance burning prevents a light-back at deflagration and stabilized burning (during and after endurance burning) of potentially explosive vapor-air and gas-air mixtures at the end of vent pipes. In a flame arrestor, spring is an important part. The spring load as well as the spring's elasticity determine when the hood is opened. In addition, the spring have to work in high temperature condition due to gas burning. Therefore, it is necessary to analyze mechanical load and elasticity of spring when gas is burned. Based on the dynamic calculation on working process of a specific flame arrestor, analysis of spring is taken. A three dimensional model for spring burned in flame arrestor by using CFD simulation. Results of the CFD analysis are input in FEM simulation to analyze structure of the spring. The simulation results can predict and estimate the spring’s load and elasticity at variation of the spring’s deflection. Moreover, the obtained result can provide makers with references to optimize design of spring as well as flame arrestor.

This study reviews concepts, theories and formulas included in standards on soil-structure interaction and also shows practical example of application for engineers. Real structures are 3 dimensional and multi degree of freedom but they are often idealized to single degree of freedom for convenience. In this study, detailed procedures to calculate soil spring constants and damping coefficients and method to model soil-structure system are explained. Additionally, case studies to judge fixed base condition and evaluation of applicability of simple analysis method based on response spectra are performed.

해양환경의 극한 환경조건에 노출 된 고정식 및 부유식 해양구조물의 안전성과 설계비용 효율성에 있어서 파랑-구조물 상 호작용의 정확한 예측은 중요하다. 본 연구에서는 규칙파 중 원형 기둥에 대한 파랑-구조물 상호작용을 해석하였다. 3차원 이상유동 (two-phase flow)을 해석하기 위해 오픈소스 전산유체역학 라이브러리인 오픈폼을 사용하였다. 4개의 원형기둥이 정사각형 배열을 이루 고 있을 때 규칙파의 입사각도에 따른 상호작용을 해석하였다. 원형 기둥 구조물에서의 wave run-up을 입사파의 기울기에 따라 비교하 였다. 원형 기둥과 입사파의 상호작용으로 인해 원형 기둥 사이에 높은 파가 생성되는 것을 확인하였다. 본 해석 결과는 구조물과 입 사파의 상호작용에 의한 air gap에 대한 연구의 기초자료로 활용될 것으로 기대된다.

In general, the design concepts of earth-observation satellites are established depending on the purposes of utilization such as commercial imagery business, public services, scientific research. Nowadays, The lightweight satellite structure is considered as an effective method for developing the earth-observation satellite. This paper introduces a design concept of the lightweight satellite structure for the constellation of earth-observation satellites. The modular design of the satellite structure is applied to save manpower and shorten the AIT process, in addition, a propulsion module is adopted to allow a hydrazine propulsion system to be installed on the satellite. The finite element method is used for the structural analysis of the satellite. The axial and lateral frequency requirements of satellite structure were verified by mode analysis. also, the margin of safety of satellite structure parts were satisfied with design requirements. As a result, the structural integrity of the suggested satellite structure is verified by mode analysis and static analysis.

Current seismic design provisions such as ASCE 7-10 provide criteria for selecting ground motions for conducting response history analysis. This study is the sequel of a companion paper (I – Ground Motion Selection) for assessment of the ASCE 7-10 criteria. To assess of the ASCE 7-10 criteria, nonlinear response history analyses of twelve single degree of freedom (SDF) systems and one multi-degree of freedom (MDF) system are conducted in this study. The results show that the target seismic demands for SDF can be predicted using the mean seismic demands over seven and ten ground motions selected according to the proposed method within an error of 30% and 20%, respectively

For estimating the seismic demand of buildings, most seismic design provisions permit conducting linear and nonlinear response history analysis. In order to obtain reliable results from response history analyses, a proper selection of input ground motions is required. In this study, an accurate algorithm for selecting and scaling ground motions is proposed, which satisfies the ASCE 7-10 criteria. In the proposed algorithm, a desired number of ground motions are sequentially scaled and selected from a ground motion library without iterations.

왕복동식 압축기에서 피스톤과 커넥팅로드는 중요한 부분이다. 이러한 주요부에 기계적 부하가 과도하게 가해지면 해당 기부 속이 손상될 수 있으며, 교체하기도 쉽지 않고 비용도 많이 든다. 따라서 내구성과 수명에 영향을 미치는 요인을 분석할 필요가 있다. 본 연구의 주요 목적은 피스톤과 커넥팅로드의 최대 응력 집중 위치를 확인하는 것이다. 이를 위해 설계된 공기압축기의 작업 공정의 동적 계산을 기반으로 피스톤 및 커넥팅로드의 응력 분석을 수행하였다. 공기압축기의 피스톤과 커넥팅로드의 3 차원 모델을 따로 설계하고, 이러한 부품들의 유한요소 해석은 수치해석적인 근사해법을 사용하였다. 피스톤은 열 경계 조건 없이 크랭크 샤프트의 각도에 따라 압 력 부하를 받는다. 시뮬레이션 결과는 피스톤과 커넥팅로드의 응력 집중 위치와 그 값을 예측하고 추정할 수 있다. 그 결과 크랭크 각도 135°와 225°에서 피스톤은 190MPa, 커넥팅로드는 123MPa 이상의 최대 등가응력이 나타났으며 이는 인장 항복강도 이하의 값이다. 또한, 커넥팅로드와 피스톤에 계산 된 안전 계수는 1보다 높게 나타났다. 더욱이, 이러한 결과는 왕복동 공기압축기 제작사에 피스톤 및 커넥 팅로드를 설계함에 있어서 최적화를 위한 참고 자료로 활용 될 수 있다.

In product development, different divisions and businesses often have heterogeneous CAD/CAE systems and methods for expressing product data, and addressing this heterogeneity creates additional costs and causes longer development periods. To ensure successful collaboration in the design process, it is therefore imperative that different CAD, CAE, and other related systems be managed in an organic and integrated manner from the initial stages of product development. Therefore, this study suggests an integrated CAD/CAE system including optimal design in a more effective and integrated manner but also to support interfacing and the collective use of design and analysis tools. To validate the proposed method, a stiffened plate example is taken as an example. It is found that the proposed method could overcome the bottleneck of CAD and CAE such as transferability of data, though CATIA and ANSYS are used at the moment.

본 논문에서는 합성단면을 갖는 구조물의 극한 거동 해석에서 요구하는 재료 및 기하학적 비선형 해석을 수행하기 위한 보 요소를 제시하였다. 제안된 요소는 기하학적 비선형성을 효과적으로 모사할 수 있는 co-rotational 정식화를 통해 도출되 었으며, 다양한 합성단면의 저항성능을 재현할 수 있도록 화이버 단면법이 요소의 내력 및 강성을 산정하는데 활용되었다. 제안된 방법을 구현할 수 있도록 해석 프로그램이 개발되었으며, 호장법을 적용하여 최대내력 발생 이후의 연성거동뿐만 아 니라 심한 비선형 응답(snap-through 또는 snapback)까지 추적해낼 수 있도록 하였다. 본 연구에서 제안된 요소 정식화와 해석 프로그램의 정확성을 검증을 위해 몇 가지 수치예제가 수행되었고, 해석결과는 제안된 요소의 정확성과 효율성을 보이 기 위해 3차원 연속체 모델 및 기존 연구의 결과와 비교되었다. 추가로 합성단면을 갖는 골조 구조물에 대한 수치예제를 통 해, 합성단면을 구성하는 재료의 탄성계수 비 및 강도 비에 따른 영향을 분석하였다. 해석결과는 외층 재료의 탄성계수가 증 가됨에 따라 준취성 거동이 나타났으며, 외층 재료의 항복강도가 높을수록 선형 거동하는 기하적 비선형 응답과 유사한 응 답을 보였다.

In recent years, the number of earthquakes has increased worldwide. There has been an extreme increase on the Korea Peninsula, which is considered a safety zone for earthquakes. In particular, in the event of earthquakes, most structures on the Korea Peninsula are severely damaged, because most are not designed to withstand them. Damage to and destruction of civil structures, such as bridges, nuclear facilities, and dams, is worse than that of other structures. It is necessary to evaluate and predict the extent of damage by earthquake magnitude, as the magnitude of earthquakes is increasing as well as the frequency. A major feature of the occurrence of earthquakes is uncertainty. For this reason, it is necessary to adopt a stochastic approach, and studies using this approach are increasing. However, although there have been several studies on bridges and nuclear facilities, there have been few studies on probabilistic seismic risk evaluation for multi-functional weirs. Thus, this study presents 3D multi-functional weirs and performs a time history analysis by using LS-DYNA, a general structure analysis program. Probabilistic seismic fragility assessment is conducted by Monte Carlo simulation.

Peeling machine has been industrially used to peel the metallic circular bar such as cast iron, cast steel, SUS series. Especially peeling process was reported to not ease in case of SUS series due to its high hardness. Structural analysis for roller jig in peeling machine was performed to evaluate the structural safety. For these purposes, stress, deformation and safety factor were investigated. As the results, maximum stress was occurred at shaft and maximum deformation was occurred at side plate in roller jig. Further since the minimum safety factor of top plate was 8.16 in case of guarantee pressure, it is considered that roller jig of peeling machine in this study was structurally safe.

Numerical behavior of FRP(Fiber Reinforced Polymer) panel in steel frame structure was evaluated through the finite element analysis in this study. In order to numerical analysis, a experimental test results was used to develop a three dimensional finite element model of steel frame specimen. Numerical results of the steel frame specimen was well predicted the experimental behavior of steel frame specimen. Based on the developed three dimensional finite element model of steel frame specimen, the behavior of FRP panel in the steel frame specimen was evaluated. From the numerical analysis results, strength of the steel frame specimen with FRP panel was governed by FRP panel. Also, diagonal compression behavior governed the FRP panel in the steel frame specimen in the numerical analysis results.