• 디지털융복합연구
• /
• 제17권7호
• /
• pp.125-130
• /
• 2019

민감도 해석은 어떤 설계 변수의 변화가 전체 시스템에 미치는 영향을 확인하기 위한 방법으로, 계산된 민감도는 구조개선 시 중요한 지표가 된다. 본 연구에서는 유한요소해석을 이용하여 설계 변수에 대한 민감도 도출 및 분석 방법과, 민감도 결과를 활용한 구조개선 방법을 제안하였다. 구조 개선이 필요한 실제 반도체 검사 장비를 이용하여 경량화를 위한 설계 변수를 선정하고 설계 변수에 대한 민감도를 유한요소법과 유한차분법을 활용하여 계산하였으며, 장비가 요구하는 과도응답(Transient Response)은 유지하면서도 무게 감소가 가능한 개선 방안을 제시하였다. 유한요소해석과 유한차분법을 이용한 민감도 분석 결과를 이용한다면 구조물의 설계 개선 시 원하는 응력 또는 변위는 만족하면서도 구조적으로 향상된 설계를 할 수 있고, 이는 반도체 검사 장비뿐만 아니라 다양한 분야에서 활용이 가능하다.

• 대한기계학회논문집A
• /
• 제30권12호
• /
• pp.1634-1641
• /
• 2006

High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a sensitivity analysis for structural and thermal characteristics was carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW table feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The results of the structural sensitivity analysis illustrated that the vertical stiffness of hydrostatic guideway for the RW table feed system greatly influenced the horizontal loop stiffness, and the results of the thermal sensitivity analysis illustrated that the heat generation rates at hydrostatic bearings and belt pulley greatly influenced the temperature rise of hydrostatic bearings and the deviation of thermal displacement between GW and RW.

• Smart Structures and Systems
• /
• 제8권2호
• /
• pp.157-172
• /
• 2011

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

• 한국정보통신학회논문지
• /
• 제20권3호
• /
• pp.639-646
• /
• 2016

본 연구에서는 특수한 상황(미끄러짐 발생 및 회전관성이 부하로 작용하는 경우)에서의 회전 엔코더 기반 측정방법의 단점을 극복하기 위하여 광 변위센서(ADNS-9500)를 사용한 비접촉식 변위 측정방법을 제안하였다. 정확한 변위 측정을 위해 데이터 수집 보드와 랩뷰를 활용하여 실험적으로 광 변위센서의 성능을 분석하였으며, 반복실험을 통해 실험조건(측정방향, 속도, 가속도, 높이, 표면 재질)에 따른 광 변위센서의 성능특성을 파악하였다. 성능실험 결과, 광 변위센서를 사용하여 정확하게 평면운동을 측정하기 위해서는 광 변위센서와 지면(대상 물체의 표면)과의 높이를 2.4 mm-3.2 mm로 일정하게 유지시켜야 하며, 각각의 축 방향, 속도, 표면 재질을 고려하여 민감도를 수정하여 변위 계산식에 적용해야 하는 것을 확인하였다.

• 한국자동차공학회논문집
• /
• 제17권5호
• /
• pp.107-114
• /
• 2009

A Common-Rail Direct Injection (CRDI) system for high speed diesel engines was developed to meet reductions of noise and vibration, emission regulations. High pressure in the common rail with electric control allows the fuel quantity and injection timing to be optimized and controlled throughout a wide range of engine velocity and load conditions. In this study, CRDI system analysis model which includes fuel and mechanical systems was developed using commercial software, AMESim in order to predict characteristics for various fuel injection components. The parameter sensitivity analysis such as throttle size, injection rate, plunger displacement, supply pressure of fuel injection for system design are carried out.

• 한국지진공학회논문집
• /
• 제18권4호
• /
• pp.161-170
• /
• 2014

Newmark-type deformation analysis has rarely been done in Korea due to the popularity of simple pseudo-static limit equilibrium analysis and detailed time-history FE/FD dynamic analysis. However, the Korean seismic dam design code updated in 2011 prescribes Newmark-type deformation analysis as a major dynamic analysis method for the seismic evaluation of fill dams. In addition, a design PGA for dynamic analysis is significantly increased in the code. This paper aims to study the seismic evaluation of four existing large fill dams through advanced FEM/Newmark-type deformation analyses for the artificial earthquake time histories with the design PGA of 0.22g. Dynamic soil properties obtained from in-situ geo-physical surveys are applied as input parameters. For the FEM/Newmark analyses, sensitivity analyses are performed to study the effects of input PGA and $G_{max}$ of shell zone on the Newmark deformation. As a result, in terms of deformation, four fill dams are proved to be reasonably safe under the PGA of 0.22g with yield coefficients of 0.136 to 0.187, which are highly resistant for extreme events. Sensitivity analysis as a function of PGA shows that $PGA_{30cm}$ (a limiting PGA to cause the 30 cm of Newmark permanent displacement on the critical slip surface) is a good indicator for seismic safety check. CFRD shows a higher seismic resistance than ECRD. Another sensitivity analysis shows that $G_{max}$ per depth does not significantly affect the site response characteristics, however lower $G_{max}$ profile causes larger Newmark deformation. Through this study, it is proved that the amplification of ground motion within the sliding mass and the location of critical slip surface are the dominant factors governing permanent displacements.

• 소음진동
• /
• 제6권1호
• /
• pp.27-34
• /
• 1996

In this paper, design sensitivity of vibration displacement and acceleration is computed and design sensitivity, the derivative information of responses with respect to design perameters, is used as a design guidance tool to reduce the vibration. First, the harmonic vibration analysis of deck and simplified ship structures is performed by finite element method and secondly continuum disign sensityivity for excessive dynamic response is computed by continuum method. Both the direct and modal frequency response methods for the finite element analysis are adopted. Sensitivities of structural components such as upper plate, side wall, bilge, bottom plate are compared and the reductionof vibration is obtained by the proper increase of thickness of each component.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.121-128
• /
• 2005

This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift for shear wall structures subject to lateral loads. To this end the displacement sensitivity depending on behavior characteristics of shear wall structures is established. Also, the approximation concept that can preserve the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Resizing sections in the stiffness-based optimal design are assumed to be uniformly varying in size and the technique of member grouping is considered for the improvement of construction efficiency Two types of 11-story shear wall structures are presented to illustrate the features of the quantitative lateral drift control technique proposed in this study.

• 한국정밀공학회지
• /
• 제18권9호
• /
• pp.147-155
• /
• 2001

A new displacement type web position control system for cold mills using QFT is presented. The control system features an inner-outer cascaded system in which the inner loop provides the position tracking control of the hydraulic system and the outer loop provides the position regulation control of the web. By the sensitivity analysis and computer simulation, it is verified that the proposed control system has better robust stability and performance than the conventional control system.

• 한국공간정보시스템학회:학술대회논문집
• /
• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
• /
• pp.96-102
• /
• 2004

This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift for 3-D steel frameworks subject to lateral loads. To this end, the displacement sensitivity depending on behavior characteristics of 3-D steel frameworks is established. Also, approximation concept that can preserve the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Resizing sections in the stiffness-based optimal design are assumed to be uniformly varying in size. Two types of 30-story frames are presented to illustrate the features of the Quantitative lateral drift control technique proposed in this study.