Nonlinear Modeling and Coupled Characteristic of Composite Structure with Complex Curvature

장준환,김재훈 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

The paper presents an experimental verification for calculating coupled stiffness matrix in complex curvature composite structure. The results of the analytical procedure using Variational Asymptotic Beam Sectional Analysis also indicate that the calculation of 2-D,beam, cross-sectional properties can then be incorporated into and 1-D beam analysis expressed coupled stiffness matrix. This paper presents the 2-D cross-sectional analysis of active anisotropic beams. Comparison between the analytical and experimental results shows that the proposed analytical procedure can provide an accurate and efficient prediction of the both deflection and flexural stiffness of multilayer composite slender structure. Verified comparison results can be used to efficiently design accurate complex slender structure properties for preliminary design and optimization.

차원축소와 복원관계를 통한 복합재료 보의 열응력 해석

장준환,안상호,Jang, Jun Hwan,Ahn, Sang Ho 한국전산구조공학회 2017 한국전산구조공학회논문집 Vol.30 No.5

Fiber-reinforced composites not only have a direction of thermal expansion coefficient, but also inevitably suffer thermal stress effects due to the difference between the manufacturing process temperature and the actual use temperature. The damage caused by thermal stress is more prominent in the case of thick composite laminates, which are increasingly applied in the aerospace industry, and have a great influence on the mechanical function and fracture strength of the laminates. In this study, the dimensional reduction and thermal stress recovery theory of composite beam structure having high slenderness ratio is introduced and show the efficiency and accuracy of the thermal stress comparison results between the 3-D finite element model and the dimension reduction beam model. Efficient recovery analysis study will be introduced by reconstructing the thermal stress of the composite beam section applied to the thermal environment by constructing the dimensional reduction modeling and recovery relations. 섬유강화 복합재료는 열팽창 계수의 방향성을 갖고 있을 뿐만 아니라 제작과정 온도와 실제 사용온도 사이의 차이 때문에 필연적으로 열응력 효과를 받게 된다. 이러한 열응력에 의한 파손현상은 실제 항공우주산업에서의 응용이 증대되고 있는 두꺼운 복합 적층판의 경우에 더욱 현저한 현상으로 적층판의 역학적 기능 및 파단강도에 큰 영향을 미치게 된다. 본 연구에서는 복잡한 재질로 구성되고 높은 세장비를 가진 블레이드 날개 구조의 차원축소 및 열 응력 복원 이론을 소개하고 3차원 유한요소모델과 비교결과를 통해 효율성과 정확성을 입증한다. 또한 차원을 축소한 모델링을 구성하고 복원이론를 이용하여 열적 환경에 적용된 복합재 보 단면의 열응력을 차원 복원하고 시각적으로 형상화하는 효율적인 복원해석 과정을 소개하고자 한다.

차원축소와 복원관계를 통한 복합재료 보의 열응력 해석

장준환,안상호 한국전산구조공학회 2017 한국전산구조공학회논문집 Vol. No.

섬유강화 복합재료는 열팽창 계수의 방향성을 갖고 있을 뿐만 아니라 제작과정 온도와 실제 사용온도 사이의 차이 때문에 필연적으로 열응력 효과를 받게 된다. 이러한 열응력에 의한 파손현상은 실제 항공우주산업에서의 응용이 증대되고 있는 두 꺼운 복합 적층판의 경우에 더욱 현저한 현상으로 적층판의 역학적 기능 및 파단강도에 큰 영향을 미치게 된다. 본 연구에서 는 복잡한 재질로 구성되고 높은 세장비를 가진 블레이드 날개 구조의 차원축소 및 열 응력 복원 이론을 소개하고 3차원 유 한요소모델과 비교결과를 통해 효율성과 정확성을 입증한다. 또한 차원을 축소한 모델링을 구성하고 복원이론를 이용하여 열적 환경에 적용된 복합재 보 단면의 열응력을 차원 복원하고 시각적으로 형상화하는 효율적인 복원해석 과정을 소개하고 자 한다. Fiber-reinforced composites not only have a direction of thermal expansion coefficient, but also inevitably suffer thermal stress effects due to the difference between the manufacturing process temperature and the actual use temperature. The damage caused by thermal stress is more prominent in the case of thick composite laminates, which are increasingly applied in the aerospace industry, and have a great influence on the mechanical function and fracture strength of the laminates. In this study, the dimensional reduction and thermal stress recovery theory of composite beam structure having high slenderness ratio is introduced and show the efficiency and accuracy of the thermal stress comparison results between the 3-D finite element model and the dimension reduction beam model. Efficient recovery analysis study will be introduced by reconstructing the thermal stress of the composite beam section applied to the thermal environment by constructing the dimensional reduction modeling and recovery relations.

차원축소와 복원관계를 통한 복합재료 보의 열응력 해석

장준환,안상호 한국전산구조공학회 2017 한국전산구조공학회논문집 Vol. No.

Fiber-reinforced composites not only have a direction of thermal expansion coefficient, but also inevitably suffer thermal stress effects due to the difference between the manufacturing process temperature and the actual use temperature. The damage caused by thermal stress is more prominent in the case of thick composite laminates, which are increasingly applied in the aerospace industry, and have a great influence on the mechanical function and fracture strength of the laminates. In this study, the dimensional reduction and thermal stress recovery theory of composite beam structure having high slenderness ratio is introduced and show the efficiency and accuracy of the thermal stress comparison results between the 3-D finite element model and the dimension reduction beam model. Efficient recovery analysis study will be introduced by reconstructing the thermal stress of the composite beam section applied to the thermal environment by constructing the dimensional reduction modeling and recovery relations. 섬유강화 복합재료는 열팽창 계수의 방향성을 갖고 있을 뿐만 아니라 제작과정 온도와 실제 사용온도 사이의 차이 때문에 필연적으로 열응력 효과를 받게 된다. 이러한 열응력에 의한 파손현상은 실제 항공우주산업에서의 응용이 증대되고 있는 두꺼운 복합 적층판의 경우에 더욱 현저한 현상으로 적층판의 역학적 기능 및 파단강도에 큰 영향을 미치게 된다. 본 연구에서는 복잡한 재질로 구성되고 높은 세장비를 가진 블레이드 날개 구조의 차원축소 및 열 응력 복원 이론을 소개하고 3차원 유한요소모델과 비교결과를 통해 효율성과 정확성을 입증한다. 또한 차원을 축소한 모델링을 구성하고 복원이론를 이용하여 열적 환경에 적용된 복합재 보 단면의 열응력을 차원 복원하고 시각적으로 형상화하는 효율적인 복원해석 과정을 소개하고자 한다.

투과 회절격자를 이용한 단일모드 외부공진기 반도체 레이저 제작

장준환,류훈철,한재원 한국통신학회 2004 한국통신학회 기타 간행물 Vol.2004 No.11

[e-스포츠 문화] 기능성 게임 활성화 방안 연구

장준환 한국멀티미디어학회 2020 한국멀티미디어학회지 Vol.23 No.1

항공기의 캐노피(Canopy) 구성 및 특성

장준환,양찬 한국방위산업진흥회 2018 國防과 技術 Vol.- No.474

말뚝으로 보강된 탄성지반상에 놓여 있는 연속기초의 해석

장준환,신수곤,장병순 부산대학교 생산기술연구소 2000 生産技術硏究所論文集 Vol.59 No.-

지반이 다소 연약하여 건물 기초를 말뚝으로 보강된 연속줄기초로 설계할 경우, 탄성지반을 무시하고, 말뚝을 탄성지점으로 한 연속보로 처리하는 것이 보통이다. 그러나 실제 기초에서는 지반반력과 말뚝반력을 모두 무시할 수 없는 경우가 많다. 본 논문은 지반반력과 말뚝반력을 동시에 고려하고 n경간의 탄성지점을 가지는 탄성지반상의 보에 대한 해석을 반무한장보와 유한장보로 구분하여 계시하고, 하중 재하위치에 따라 반무한장보 및 유한장보로 해석해야 할 범위를 제시하였다 In this paper, the method of analysis for the girder supported with piles on the elastic soilmedium is proposed. The girder supports with piles on the elastic soil medium is often used as those of crane rail at a ship yard. For the purpose of practical design, these girders were often regarded as continuous beams elastically supported with piles. Actually, the method of ana1ysis for these girders should be considered as analysis of girder supported with piles on the elastic soil medium. From the proposed method, we can calculate bending moment and shearing force of these girders, after obtaining the reaction of piles by calculating the deflection of pile support point due to external load and pile reaction.

보건의료계 학생에서 학업적 대인관계가 학업소진에 미치는 영향

장준환,배선환,김경재,김도영,박준성,이승현,박미라,김도환,Jang, Junhwan,Bae, Seonhwan,Kim, Gyungjae,Kim, Doyoung,Park, Junseong,Lee, Seunghyeon,Park, Mira,Kim, Do-Hwan 연세대학교 의과대학 2019 의학교육논단 Vol.21 No.2

There are several dimensions of academic burnout experienced by medical and health science college students. The purpose of this study was to examine the effects of academic relationships on academic burnout. Data was collected from 476 Eulji University students using an online survey over 4 days in April of 2018. Of the 264 respondents, 111 studied medicine (42.0%), 105 studied nursing (39.8%), and 48 studied clinical pathology (18.1%). The questionnaire was composed of the following sections: demographics (four questions), general life characteristics (seven questions), academic enthusiasm (eight questions), academic relationships (15 questions), and academic burnout sub-dimensions (partially revised Maslach Burnout Inventory-Student Survey Scale) (11 questions). T-tests and one-way analysis of variance were performed to illustrate the differences among the three departments. The effects of academic relationships and academic enthusiasm on academic burnout were analyzed using linear regression. Comparing the three departments, academic burnout was not found to be statistically significant (p=0.296). However, medical students' academic enthusiasm was significantly lower (p<0.001) and academic relationships were significantly higher (p<0.001) than nursing and clinical pathology students. The difference in academic burnout among the three departments was not significant. However, medical students have stronger academic relationships, while nursing and clinical pathology students were more focused on academics. Relationships and academic enthusiasm contribute to reducing academic burnout. Therefore, strategies need to be developed to deal with academic burnout considering relationship factors.

강박증 환자에서의 Mismatch Negativity 이상에 관한 연구

장준환,신경순,손준희,권준수,Jang, Joon-Hwan,Shin, Kyung-Soon,Son, June-Hee,Kwon, Jun-Soo 대한불안의학회 2010 대한불안의학회지 Vol.6 No.1

Objective : Mismatch negativity (MMN) provides an electrophysiological index of an involuntary attention switching process. This study investigated MMN anomalies and their relationship to clinical variables in patients with obsessive-compulsive disorder (OCD). Methods : Study participants were 29 OCD patients and 24 normal controls. We used a 128-channel EEG to measure MMN during a passive oddball paradigm. Then we assessed the correlations between MMN amplitudes and clinical measures. Results : The OCD patients exhibited significantly greater MMN amplitude compared to the controls. Also, the right frontal lobe MMN amplitudes correlated significantly to the OCD patients' Yale-Brown Obsessive Compulsive Scale total scores (r=-0.520, p=0.005). Conclusion : These results suggest that MMN anomalies in OCD patients reflect a monitoring circuit dysfunction, raising the possibility that the OCD's pathophysiology includes glutamatergic dysfunction.