콤플렉스법을 이용한 U-채널 성형의 스프링백 강건 설계

인정제(Jeong-Je Yin),김경모(Kyung-Mo Kim),박종천(Jong-Cheon Park) 한국기계가공학회 2013 한국기계가공학회지 Vol.12 No.1

Variations of springback in stamped parts are induced by the uncontrollable noises including the variation of incoming material properties, lubrication and other forming process parameters. Reduction of springback variation is very important during springback compensation processes on stamping dies and assembly processes. To reduce the variation of springback, a robust optimization methodology which uses complex method combined with orthogonal array is proposed. The proposed method is applied to the robust design of U-channel die for the reduction of side wall curl. It is shown that the drawbead and die radius of U-channel draw die can be effectively optimized by the proposed method.

카오스모스 시학과 김지하 담시의 구조형성방식 -「비어(蜚語)」와 「똥바다」를 중심으로

김란희 ( Kim Ran-hee ) 국제어문학회 ( 구 국제어문학연구회 ) 2009 국제어문 Vol.45 No.-

본고는 김지하 담시의 구조형성 방식을 카오스모스 시학으로 살펴보고자 한다. 여기서 언급하는 카오스모스 시학이란 현대시학이 추구하는 다의성의 본질을 이해하기 위해서 현대 과학이 다루고 있는 우연성, 불확정성, 개연성, 애매모호함, 다가치성 등을 예술에 접목시켜 시학적 지평을 학제간의 영역으로 넓혀보고자 하는 방법론이라 할 수 있다. 카오스와 복잡성에 대한 현대 과학의 발전은 하나의 시학을 가능하게 하는데, 그것은 불연속성, 복잡성, 자기 조직화 이론으로 대변되는 카오스모스 시학으로 문학 텍스트의 복잡성과 밀도, 결 등을 은유적으로 살펴볼 수 있는 하나의 도구가 될 수 있다. 이는 김지하 시인 스스로가 담시 발표 이후 꾸준히 카오스모스와 자기조직화의 시론을 내세우며 민중의 노래(민요와 판소리, 각설이 타령, 배뱅이 굿 등)가 대표적인 카오스모스와 자기 조직화의 사상을 보여주는 예술장르라고 밝힌 점과도 일치 한다. 본고에서 민중 문학이 현실을 반영하는 지시적 코드로만 평가받았던 연장선에서 벗어나 김지하 텍스트에 대한 시학적 접근의 도구로 카오스모스 시학을 택했던 것은 김지하의 담시 텍스트가 지니고 있는 지시성과 애매성, 복잡성, 다층성 등을 동시에 살펴볼 수 있다는 점에 주목했기 때문이다. 이는 김지하 담시에서 감지되는 혼돈과 질서, 질서와 혼돈이라는 역설적 정합의 미학을 시학적 차원에서 규명해보고자 하는 작은 시도라 할 수 있다. <불연속성과 복잡성>, <자기 방해의 패턴>, <자기조직화의 원리>로 대표되는 카오스모스 시학을 통해 살펴본 김지하 담시는 불연속성과 복잡성의 조우를 통해 선형적이고 직선적인 줄거리로부터 벗어난 것처럼 보이지만 나름대로의 질서를 형성하면서 전체성에 복무하고 있는 다층성을 지니고 있다. 이는 `혼돈 속의 질서`라는 역설적 정합 과정을 통한 담론의 조직화로, 기왕의 민중 문학이 지녀왔던 단성성의 한계를 뛰어넘는 새로운 시적 창조를 보여줌과 동시에 오히려 메시지를 한층 더 강화해내는 효과를 낳고 있다. 또한 모순 어법을 통해 모순적인 의미의 충돌과 혼합을 통한 언어의 테크닉을 보여주고 있는데, 이는 풍자의 결을 다층적으로 보여주는 효과를 낳고 있다. 이는 서로 다른 언어의 이질성이 융합되어 제 3의 의미를 생성해내는 시 담론의 조직화 방식으로도 볼 수 있다. 이에 따라 텍스트의 다의미성은 형성되며 독자들은 당시의 시대 상황을 다층적으로 지각하게 된다. 아울러 담시를 이루고 있는 각각의 분리된 이야기는 스스로 자기 조직화를 꾀하면서 더 넓은 영역 안에서 통합되고 있는데, 그것은 마치 단순한 것들이 에너지를 이용해 결합하면서 복잡한 것으로 변해가는 자기 조직화 논리와 맞닿은 것으로, 우연적 요소가 필연적 기제로 작동을 하고 있는 것이다. 그 안에서 각각의 요소는 불연속성과 복잡성이라는 상호 교호 작용을 통해 자기 조직화를 이루어내고 있다. 이에 따라서 김지하 담시 텍스트에서 그동안 읽혀왔던 지배/ 피지배, 억압/피억압, 권력층/민중의 이분법적 대립 구도는 이러한 분리와 결합의 간섭과 충돌 과정을 통한 열림과 닫힘의 끊임없는 언어적 실험으로 다시 읽을 수 있는 것이다. This study intends to explore into the Kim Ji-ha`s lay structure-forming method in terms of "chaosmos poetics". The chaosmos poetics refers to a method that integrates the accidentality, indeterminacy, probability, ambiguity and muti-valuableness which modern poetics addresses with art and attempts to expand the poetics horizon to the interdisciplinary sphere in order to understand the essence of the equivocality which modern poetics seeks. The development of the modern science on chaos and complexity made one poetics possible, which could be a tool which would metaphorically look to the complexity, density and texture of literary texts with a chaosmos poetics represented by discontinuity, complexity and self-organization theories. This coincides with an assertion that poet Kim Ji-ha has claimed that popular songs("minyo", or folk song, "pansori", or traditional Korean narrative song, "gakseolitaryeong" or singing beggar`s ballards and "Baebaengi gut", or Baebangi`s shaman ritual, etc) are the art genre showing the thought of the representative chaosmos and self-organization while steadily promoting the poetics of chaosmos and self-organization since the release of the selfproclaimed narrative poetry. In this study, the reason why I chose the chaosmos poetics as a tool for the poetic approach to Kim Ji-ha texts, deviating from the prolongation that has been only evaluated as a reference code which popular literature reflects reality is because I looked to a point that I could simultaneously examine the reference, ambiguity, complexity and multi-layeredness which his lay texts carry. This could be a little attempt that tries to explore into the paradoxically thesis-antithesis aesthetics of chaosmos vs order and order vs. order which is sensed in Kim Ji-ha lay from the perspective of poetics. The Kim Ji-ha lay which were investigated via chaosmos poetics represented by "discontinuity and complexity", "self-obstructive pattern", and "self-organization principle", seem to be deviated from a curved and linear storyline via an encounter of discontinuity and complexity but have their-own multi-layeredness that both shapes order and serves to wholeness. This is both an organization of the lay via a paradoxical thesis-antithesis process of the so-called "order in chaos" and a mani -festation of the new poetic creation beyond the limit of the unisexuality which the past popular literature held, simultaneously giving rise to an effect that enforces a message much more. And Kim Ji-ha lay show a language technique through the conflict and mix of contradictory meanings via a oxymoron, which brings about an effect that demonstrates the texture of satires in a layeredness way. It would be a poetic lay-forming way which generates the third meanings as a result of the heterogeneity of different languages being converged each other. Thus, the multi-meaningfulness of the text is formed and readers perceive their contemporary multi-layered circumstances. Further, the differently separate stories which consist of a lay seeks a self- organ -ization on their own and are integrated into a wider sphere, which is connected to the logic of the self-organization of as if simple objects are combined each other by using an energy and transformed into a complex thing, accidental elements functioning as a necessary mechanism. As it were, each element seeks a self-organization via an interaction of discon -tinuity and complexity in the mechanism. Hence, the dichotomical confrontation scheme of the ruling/the ruled, the suppressing/the suppressed and power class/the populace that have been read in the Kim Ji-ha lay texts thus far would be newly read with a ceaseless language experiment of opening and closing via the inter -ference and conflict of such separation and combination.

A study on convergence and complexity of reproducing kernel collocation method

Hu, Hsin-Yun,Lai, Chiu-Kai,Chen, Jiun-Shyan Techno-Press 2009 Interaction and multiscale mechanics Vol.2 No.3

In this work, we discuss a reproducing kernel collocation method (RKCM) for solving $2^{nd}$ order PDE based on strong formulation, where the reproducing kernel shape functions with compact support are used as approximation functions. The method based on strong form collocation avoids the domain integration, and leads to well-conditioned discrete system of equations. We investigate the convergence and the computational complexity for this proposed method. An important result obtained from the analysis is that the degree of basis in the reproducing kernel approximation has to be greater than one for the method to converge. Some numerical experiments are provided to validate the error analysis. The complexity of RKCM is also analyzed, and the complexity comparison with the weak formulation using reproducing kernel approximation is presented.

In-Process합성에 의한 고기능 금속간화합물의 복합성형

한정현,박성갑,박용호,Han, Jung-Hyun,Park, Seong-Kab,Park, Yong-Ho 한국분말야금학회 2006 한국분말재료학회지 (KPMI) Vol.13 No.6

[ $MoSi_2$ ] alloys with Al, B or Nb were prepared by an advanced consolidation process that combined mechanical alloying with pulse discharge sintering (complex forming) to improve the mechanical properties. Their microstructure and mechanical properties were investigated. The $MoSi_2$ alloys fabricated by complex forming method showed very fine microstructure when compared with the sample sintered from commercial $MoSi_2$ powders. Alloys made from powders milled in Ar gas had fewer silica or alumina phases as compared to their counterparts sintered from powders milled in air. In densification of the sintered body, addition of B was more effective than Al or Nb. Both Victors hardness and tensile test indicated that the alloy fabricated by the complex forming method showed better properties than the sample sintered from commercial $MoSi_2$ powders. The Al added alloy sintered from the powders milled in air had the superior mechanical properties due to the suppression of $SiO_2$ and formation of fine $Al_2O_3$ particles.

2속성 강건 설계를 이용한 박판성형공정의 최적화

김경모(Kyung-Mo Kim),인정제(Jeong-Je Yin),박종천(Jong-Cheon Park) 한국기계가공학회 2014 한국기계가공학회지 Vol.13 No.2

Fractures and wrinkles are two major defects frequently found in the sheet metal forming process. The process has several noise factors that cannot be ignored when determining the optimal process conditions. Therefore, without any countermeasures against noise, attempts to reduce defects through optimal design methods have often led to failure. In this study, a new and robust design methodology that can reduce the possibility of formation of fractures and wrinkles is presented using decision-making theory. A two-attribute value function is presented to form the design metric for the sheet metal forming process. A modified complex method is adopted to isolate the optimal robust design variables. One of the major limitations of the traditional robust design methodology, which is based on an orthogonal array experiment, is that the values of the optimal design variables have to coincide with one of the experimental levels. As this restriction is eliminated in the complex method, a better solution can be expected. The procedure of the proposed method is illustrated through a robust design of the sheet metal forming process of a side member of an automobile body.

Numerical Investigation and Design of Cold-formed Steel Angle Columns with Complex Edges under Axial Compression

Jun-Feng Zhang,Mengmeng Feng,En-Feng Deng,Shiyun Pang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

Currently, cold-formed steel (CFS) is widely used in fabricated steel structures for high strength-to-weight ratio and ease for installation. However, limited research is available in the literature on the CFS angle columns with complex edges under axial compression. In this paper, the axial compressive capacity of the CFS angle columns with complex edges was numerically studied. The distortional buckling characteristics of 1008 CFS angle sections with complex edges were analyzed by finite strip software CUFSM. Detailed non-linear finite element model (FEM) was developed based on finite element program ABAQUS and verified by comparing with test results. The verification indicated that the developed FEM could well predict the ultimate strength and failure model of the specimens. Using the validated FEM, an extensive parametric study comprised of 330 models was conducted. The influences of the specimen length, the edge ratio and the limb-width ratio of the angle section on the axial compressive capacity of CFS angle columns with complex edges were evaluated. Then an improved direct strength method (DSM) was proposed based on the existing DSM. The evaluations based on tests and FEA results showed that using the modified DSM to predict the load-bearing capacity of the CFS angle columns with complex edges was feasible.

Distortional–Global Interactive Buckling of Thin-Walled Columns with Complex Lips

Navin K. Vincent,Allen Varghese,S. S. Ajeesh 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4

When the interaction of buckling modes in thin-walled steel columns are considered, most of the existing research deals with local–distortional mode or local–global mode interaction. The studies available on compression members undergoing distortional–global buckling mode interaction is comparatively less. This study analyses the behaviour of cold-formed thin-walled compression members having complex lips under axial compression and undergoing interaction of distortional–global buckling (D–G) modes. Finite element analytical (FEA) study is performed on members with complex lips for a range of geometries after validating the finite element model with existing experimental results. Member dimensions are selected based on elastic buckling analysis results such that the member fails predominantly in D–G interaction. Comparison of nonlinear finite element results are made with; (1) direct strength method (DSM) for the design of compression members, and (2) modified DSM for columns considering the interaction of buckling modes proposed in the literature. Modifications are proposed for the existing DSM expression to incorporate the D–G interaction, which provides a closer comparison with FEA results.

한국어 교육에서 복합 형태 ‘에 대해(서)’, ‘에 대한’의 연구

임진숙(Lim Jin-Suk) 우리말학회 2018 우리말연구 Vol.55 No.-

이 연구는 모어 화자의 사용 빈도가 높고 한국어 학습에서 필수적인 항목으로 제시되는 ‘에 대해(서)’, ‘에 대한’의 제시 방법과 의미, 용법을 분석하여 한국어 교육 방법을 고안할 수 있는 시사점을 제언하는 것에 목적이 있다. 이를 위해 한국어 교재와 문법서를 분석하였는데 ‘에 대해(서)’의 형태적 제시가 통일되지 않은 것을 알 수 있었다. 또한 관형형 ‘에 대한’은 ‘에 대해(서)’의 제시 후에 추가적 설명으로 제시되어 문법적 설명 제시가 부족한 경우가 많았다. 다음으로 한국어 능력시험에서 ‘에 대해(서)’, ‘에 대한’의 문장을 추출하여 선행부와 후행부를 나누어 분석하고 호응관계를 살펴보았다. 선행부에는 직접적 대상이 되는 구체적 내용과 전체적인 화제 내용이 되는 포괄적 내용으로 구분할 수 있었다. 후행부는 심리표현, 언어표현, 사고표현으로 나누어 제시할 수 있으며 선행부에 나타난 표현과 공기할 수 있는 표현을 확인하여 제시하는 것이 중요하다고 보았다. 이러한 결과를 바탕으로 시사점을 제언하여 ‘에 대해(서)’, ‘에 대한’의 교육 방안 마련에 도움을 주고자 하였다. The purposes of this study are to analyze the presentation methods, meanings, and uses of ‘~e daehae(seo)’, ‘~e daehan,’ which record such high frequency of usage among native speakers that they are provided as essential items in Korean study, and propose implications to devise educational methods for Korean. For these purposes, the investigator analyzed teaching materials and grammar books for Korean and found that there was no unity among the morphological presentations of ‘~e daehae(seo).’ Its modifier form ‘~e daehan’ was presented as an additional explanation after ‘~e daehae(seo),’ thus lacking in the provision of grammatical explanation in many cases. The study extracted sentences containing ‘~e daehae(seo)’ or ‘~e daehan’ in the Test of Proficiency in Korean, analyzed them in the former and latter part, and examined them in grammatical agreement. The former part consisted of specific content to cover the direct subject and comprehensive content to cover overall topic content. The latter part was comprised of psychological, linguistic, and thinking expressions. It was important to check and present expressions in the former part and their equal expressions. Based on these findings, the study proposed some implications to help with educational plans for ‘~e daehae(seo) ’, ‘ ~e daehan’.

알루미늄합금박판의 복합형상에 대한 성형한계

김민우(M. W. Kim),예상돈(S. D. Ye),허관도(K. D. Hur) 한국소성가공학회 2015 한국소성가공학회 학술대회 논문집 Vol.2015 No.5