철도차량의 설계 민감도 해석을 위한 효율적인 알고리즘 개발

배대성(Bae Dae Sung),조회제(Cho Heui Je),백성호(Beak Sung Ho),이관섭(Lee Kwan Sup),조연옥(Cho Yun Ok) 한국철도학회 1998 한국철도학회 학술발표대회논문집 Vol.- No.-

Design sensitivity analysis of a mechanical system is an essential tool for design optimization and trade-off studies. This paper presents an efficient algorithm for the design sensitivity analysis of railway vehicle systems, using the direct differentiation method. The cartesian coordinate is employed as the generalized coordinate. The governing equations of the design sensitivity analysis are formulated as the differential equations. Design sensitivity analysis of railway vehicle systems is performed to show the validity and efficiency of the proposed method.

2007년 개정 과학교과서의 7학년 지구과학 탐구활동 분석

배대성 ( Dae Sung Bae ),김재영 ( Jae Young Kim ),조규성 ( Kyu Seong Cho ) 전북대학교 과학교육연구소 2012 科學敎育論叢 Vol.37 No.-

The purpose of this study is to be basic materials for choosing textbooks and reconstructing contents appropriate for the level of students and state of schools. In order to collect the materials the part of earth science of inquiry activities represented in 7th grade textbooks which were changed by the revised curriculum in 2007 was analyzed into contents processes and situations. First of all the result of comparative analysis on the number of times and subjects of inquiry contents in 9kinds of textbooks showed that there were some meaningful differences in the chosen textbooks. The number of times and subjects in inquiry activities shows that representing 192 in the 7th grade textbooks the average one of them is 21.3. Every textbook contains all the necessary inquiry subjects but B,C and D textbook represents contents that are not supposed to be covered in curriculum gruide. Second the result of comparative analysis on inquiry processes shows that in 7th grade textbooks the elements of observation and measurement account for 9.9(46.5%) on the average and the ones of interpretation and generalization do 7.8(36.6%) which take up more than 80%. This is because the area of geology in 7th grade Earth Science mostly covers to observe minerals or rocks and to generalize the facts through a represented earthquake and volcanic zone. Third the result of comparative analysis on inquiry situations shows that in 7th grade textbooks the element of pure science and the one of natural environment account for 15.2(71.4%) and 3.9(18.3%) respectively which take up about 90%. It can be explained that there are some limits to apply geology covered in 7th grade textbooks to daily life or industry.

질화처리가 금형펀치(SKH51)의 마모 특성에 미치는 영향

배대성(Dae-Sung Bae),조상철(Sang-Chul Jo) 산업기술교육훈련학회 2009 산업기술연구논문지 (JITR) Vol.14 No.1

Recently, as the component industry has grown up with the high technology, metallic pattern is needed to have special properties such as precise processing, heat resistance, wear resistance, fatigue resistance and mass product. For these reason, high speed steels with good physical and mechanical properties is favored in the making of the metallic pattern. This study is focused on examining the micro-structure of nitrided case and relationship variation of hardening and wear behavior generated by vacuum heat treatment to grasp the properties of high speed steel for metallic pattern. Also, to understand the effect of ion nitriding for wear resistance of high speed steels the experiment to examine how much microstructure of nitrided layer and hardness variation affect on the wear behavior was conducted according to the ion nitrided treatment and behavior of compound layer and precipitation layer constituting nitrided layer. The results of experiment are as follows: The optimal austenitizing temperature reached at 1250℃ under the condition of the hardness value and surface of roughness in 1,170 ℃ and absorption energy showed 1,170℃ in the case of 1,100℃. Ion nitrided specimen, under these experimental condition, shows the existence of the area of two phases with matrix and carbides and also shows the value of W, Mo, Cr and V components higher in these area. The ruling wear mechanism turned out to be adhesion wear before ion nitriding specimen to be tempered repeatedly twice after quenching and sub-zero treatment but it is abrasive wear and the wear resistance is more enhanced after that process.

다물체 시스템의 동적 거동에 대한 최적설계 기법

배대성(Dae Sung Bae),김민수(Min Soo Kim),이순걸(Soon Geul Lee),조희제(Hui Je Cho),백성호(Sung Ho Baek),조기훈(Ki Hoon Cho) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

Recently, industrial design requires the validation of multi-body dynamics, non-linear FE analysis, and test etc. However, the conventional DSA based approaches cannot be used in these disciplinary. Since a design problem related to the multibody dynamics and non-linear FE analysis is very complicated, their design sensitivity analysis process can be very tedious and difficult to find an optimized design within a limited time. So this represents that analytical design sensitivity is impossible in these areas. This is a sequential approximate optimization based on the meta-models such as Kriging and RSM etc. Since the sampling points for the meta model come from a D.O.E technique which has been very effective for a test field, its performance is very powerful. It generates the approximate objective function and solves the optimization problem using the ALM method. Then, a new design is given to analysis module. These processes are repeated until finding a tolerable design optimization. In this paper, a numerical example is introduced and it is optimized with the proposed algorithms.

구속된 다물체 시스템의 선형화에 관한 연구

배대성(Dae sung Bae),최진환(Jin hwan Choi),김선철(Sun chul Kim) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4

This research proposes an implementation method of linearized equations of motion for multibody systems with closed loops. The null space of the constraint Jacobian is first pre multiplied to the equations of motion to eliminate the Lagrange multiplier and the equations of motion are reduced down to a minimum set of ordinary differential equations. The resulting differential equations are functions of all relative coordinates, velocities, and accelerations. Since the coordinates, velocities, and accelerations are tightly coupled by the position, velocity, and acceleration level constraints, direct substitution of the relationships among these variables yields very complicated equations to be implemented. As a consequence, the reduced equations of motion are perturbed with respect to the variations of all coordinates, velocities, and accelerations, which are coupled by the constraints. The position, velocity and acceleration level constraints are also perturbed to obtain the relationships between the variations of all relative coordinates, velocities, and accelerations and variations of the independent ones. The perturbed constraint equations are then simultaneously solved for variations of all coordinates, velocities, and accelerations only in terms of the variations of the independent coordinates, velocities, and accelerations. Finally, the relationships between the variations of all coordinates, velocities, accelerations and these of the independent ones are substituted into the variational equations of motion to obtain the linearized equations of motion only in terms of the independent coordinate, velocity, and acceleration variations.

상대좌표를 이용한 3차원 미디어 이송장치에 대한 실험방법과 Simulation에 대한 연구

배대성(Dae Sung Bae),조희제(Heui Je Cho) 한국소음진동공학회 2005 한국소음진동공학회 학술대회논문집 Vol.2005 No.11

정적 처짐에 대한 실험과 시뮬레이션을 통한 종이의 물성치 추정

배대성(Dae Sung Bae),조희제(Hui Je Cho),이근표(Geun Pyo Lee),최진환(Jin Hwan Choi),김민수(Min Soo Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

This proposes a technique to estimate the material property of a paper using an experimental method and commercial CAE software. Under gravitation, if one side of the paper is attached to the ground, the other side is largely deformed. Also, since the paper has an orthotropic characteristic due to its treatment, the deformations in two orthogonal directions of the dry paper are different. This introduces an experimental method to measure the static deformation of the paper with the orthotropic characteristics. And then, virtual prototype which can represent the static behavior are built by using the commercial CAE software of RecurDyn™/MTT3D. The software has been used by engineers in printer makers. While comparing the deformations from the experiment and simulation, a design optimization technique in the commercial CAE software of RecurDyn™/AutoDesign is used to estimate the material property such as Young’s modulus and shear modulus of the paper.

An Efficient Dynamics Analysis using a Parametric Generalized Coordinate

Dae-Sung Bae(배대성),Chul-Ho Lee(이철호),Sang-Ho Lee(이상호) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

A parametric generalized coordinate formulation for the equations of motion and kinematic constraint equations is presented. The equations of motion and the constraint equations are simplified by introducing parametric generalized coordinates in addition to the Cartesian generalized coordinates. The proposed method has been demonstrated to be very effective for the implicit implementation of the equations of motion and constraints. Sparse matrix solver combined with the proposed formulation plays a key role in the implicit implementation. An automobile example is solved to demonstrate the efficiency of the proposed method.

무전원 비콘 시스템 개발을 위한 에너지 하베스팅 기술 연구

이상진(Sang-Jin Lee),최대도(Dae-Do Choe),김남윤(Nam-Yoon Kim),배대성(Dae-Sung Bae) 한국통신학회 2016 한국통신학회 학술대회논문집 Vol.2016 No.1

유물 편경의 음향 분석을 통한 아악 황종음고의 추정

유준희,박정우,배대성,김형준,성굉모,노정욱,고현우,Yoo, June-Hee,Park, Jeong-Woo,Bae, Dae-Sung,Kim, Hyung-Jun,Sung, Keong-Mo,Noh, Jung-Uk,Koh, Hyun-Woo 한국음향학회 2011 韓國音響學會誌 Vol.30 No.8

본 연구의 목적은 국내 여러 기관에 분산 소장 중인 편경 유물을 체계적으로 파악하고, 음향을 측정 분석하여 황종음고의 기본 진동수를 추정하는 것이다. 이를 위하여 국립고궁박물관, 국립국악원, 국립국악고등학교에 소장 중인 241매 유물 경석의 간지별, 율명별 분포를 파악하였다. 보다 타당한 대푯값을 찾기 위하여 17매의 유물 황종 경석에서 측정한 기본 진동수를 군집 분석하였으며, 간지별로 경석을 분류하여 삼분손익법으로 황종음고를 역추정하였다. 경석의 간지와 기록이 일치하는 계축년 간지의 경석 22개로 추정한 황종음고의 기본진동수는 266.9 Hz, 정유년 경석과 갑자년 경석으로 추정한 값은 262.4~262.5 Hz, 20세기에 해당하는 간지인 갑진년, 소화 12년, 소화 13년 경석으로 추정한 값은 258.7~259.3 Hz 등 시대에 따라 변해온 것으로 추정된다. 과거 유물에 대한 접근이 어려웠던 시대에 일부 유물로 황종음고를 추정한 것에 대해서 본 연구는 경석 유물 전수에 대한 음향 분석을 바탕으로 황종음고를 추정한 것에 의의가 있다. This study aimed to figure out the numbers and note distributions and sexagenary cycles of old pyeongyoungs systematically, and estimate the nominal frequency of whangjongeum, the Korean tradition pitch standard. As a total 214 old stones in the National Palace Museum, the National Kukak Center, the Kukak National High School were counted by notes and sexagenaries. The nominal frequencies of 17 old whangjong stones' sounds were categorized by cluster analysis method. Using nominal frequencies of stones according to their sexagenaries and Korean traditional intonation were used to estimate the nominal frequencies of the whangjong. The nominal frequency can be estimated by 22 Keychuk stones as 266.9 Hz, by Cheongyu and Gabja stones as 262.4~262.5 Hz, and by Gabjin, Sowha 12 and Sowha 13 as Estimating by 22 Kyechuk stones which were matched with the records. These results seem to be more reliable, because it is based on the whol samples of old pyeongyoungs, while the former studies have been based on couples of whangjong stones' sounds.