• Title/Summary/Keyword: detail of joint

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충돌 안전도 해석을 위한 $5^{th}$ percentile 성인 여성 유한요소 모델 개발 - Part II 신체 부위 별 상세 모델 개발 (Development of $5^{th}$ percentile female finite Element Model for Crashworthiness Simulation - Part II Detail Modeling of Internal Components)

  • 나상진;최형연;이진희
    • 대한의용생체공학회:의공학회지
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    • 제25권4호
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    • pp.283-288
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    • 2004
  • 본 논문에서는 작은 여성 승객의 충돌해석을 위한 유한요소 모델링에 대하여 Part I 의 분절된 강체 모델에 이어 소개하고 있다. 추가로 모델링 된 상세한 팔, 다리 및 내부 요소들이 분절된 강체 모델에 합체되어 충돌 상해 즉 골절 또는 탈골 등을 예측하게 된다. 이러한 사지 및 내부 요소들의 거동 특성은 확보된 사체 실험 결과와 비교, 검증하였다. 따라서 본 논문에서 제안하고 있는 작은 여성 인체 모델은 충돌 상해 기구학의 조사 및 현존하는 충돌 더미의 생체 충실도를 보완하는데 활용될 수 있다.

Axial impact behavior of confined concrete filled square steel tubes using fiber reinforced polymer

  • Zhang, Yitian;Shan, Bo;Kang, Thomas H.K.;Xiao, Yan
    • Steel and Composite Structures
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    • 제38권2호
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    • pp.165-176
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    • 2021
  • Existing research on confined concrete filled steel tubular (CCFT) columns has been mainly focused on static or cyclic loading. In this paper, square section CCFT and CFT columns were tested under both static and impact loading, using a 10,000 kN capacity compression test machine and a drop weight testing equipment. Research parameters included bonded and unbonded fiber reinforced polymer (FRP) wraps, with carbon, basalt and glass FRPs (or CFRP, BFRP, and GFRP), respectively. Time history curves for impact force and steel strain observed are discussed in detail. Experimental results show that the failure modes of specimens under impact testing were characterized by local buckling of the steel tube and cracking at the corners, for both CCFT and CFT columns, similar to those under static loading. For both static and impact loading, the FRP wraps could improve the behavior and increase the loading capacity. To analyze the dynamic behavior of the composite columns, a finite element, FE, model was established in LS-DYNA. A simplified method that is compared favorably with test results is also proposed to predict the impact load capacity of square CCFT columns.

SM570-TMC 강의 잔류응력 특징에 관한 실험적 연구 (An Experimental Study on the Characteristics of Residual Stresses in Welds of SM570-TMC Steels)

  • 박현찬;이진형;김재환;최의홍;최명기;장경호
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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    • pp.276-278
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    • 2005
  • Bridge constructed recently is preferred to have a long span and a simple structure detail considering not only functions as bridge but scenic beauty, maintenance, construction term and life cycle cost, etc. Therefore, it demands a high quality steel like a thick plate steel and a high performance steel. A TMCP steel produced by theme-mechanical control process is now spotlighted due to the weldability for less carbon equivalent. It improved at strength and toughness in microstructure. Resently the SM570-TMC steel, a high strength TMCP steel whose tensile strength is 600MPa, is developed and applied to steel structures. But, for the application of this steel to steel structures, it is necessary to elucidate not only the material characteristics but also the mechanical characteristic of welded joint. In this paper, we investigated the characteristics of residual stresses generated by welding of SM570-TMC steels through an experimental study

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철근콘크리트 특수모멘트골조의 보-기둥 접합부 실험체의 내진성능평가 (Seismic Evaluation of Beam-Column Joint Specimens of RC Special Moment Frames)

  • 이기학;석근영;정찬우;신영식;강주원
    • 한국공간구조학회논문집
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    • 제8권2호
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    • pp.85-93
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    • 2008
  • 본 연구는 철근콘크리트 특수모멘트골조(SMF)내 보-기둥 접합부의 비탄성 회전능력에 대한 연구결과를 조사한 것이다. 모든 실험체들은 ACI 318-02에 정의된 설계 및 세부지침에 따라 특수모멘트골조로 분류되었다. AISC(2002)기준에서 모멘트골조의 접합부에 대한 내진성능의 만족 기준을 이용하여 보-기둥 접합부를 평가하였다. 총 39개의 실험체들에 대해 자세하게 조사되었다. 특수모멘트골조에 대한 내진설계기준을 만족하는 대부분의 접합부들은 3%의 소성회전까지 휨강도의 심각한 감소 없이 연성이 유지되었다. 이는 특수모멘트골조 접합부들에 대한 엄격한 콘크리트 내진설계 규정에 따른 것으로 조사되었다. 접합부내의 횡방향 보의 존재는 보-기둥 접합부의 구속력과 전단에 대한 저항성을 증가시킨 것으로 조사되었다 접합부 전단응력에 대한 ACI 328-02 제한조건을 만족하는 모든 특수모멘트골조의 접합부들은 요구되는 내진성능을 만족하는 것으로 나타났다.

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SD700 확대머리 철근의 겹침이음 상세를 적용한 단차가 있는 RC 보의 구조성능 평가 (Evaluation of Structural Performance of RC Beam with Different Depths to Lap Splice Detail of SD700 Headed Bar)

  • 이지형;김승훈
    • 한국구조물진단유지관리공학회 논문집
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    • 제25권6호
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    • pp.262-269
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    • 2021
  • 본 논문은 SD700 확대머리철근의 겹침이음을 이용한 단차가 있는 보의 접합상세를 개발하기 위하여 실시한 구조성능평가 실험결과를 나타낸다. 실험변수는 주철근의 겹침이음길이, 철근 항복강도, 단부정착상세 등이다. 모든 실험체에 대하여 춤이 작은 보(B2)의 하부 주철근은 확대머리철근을 적용하였으며, 춤이 큰 보(B1)의 하부 주철근은 일자형 확대머리철근, 90° 갈고리형 확대머리철근 등 두 가지 상세로 이음방법을 적용하였다. 실험결과, SD500과 SD600을 적용한 실험체들은 겹침이음부에서 모두 휨파괴되었으며, 이로 인하여 최대내력은 유사하게 나타났다. SD500을 적용한 실험체들에 대하여, B1의 주철근을 90°갈고리형 확대머리철근으로 적용한 상세가 확대머리철근에 비하여 겹침이음부의 수평균열을 억제하였다. SD700의 확대머리철근을 사용한 실험체는 취성적인 정착파괴가 나타났으며, 겹침이음길이의 증가에 따라 최대내력이 증가하였다. SD700의 확대머리철근을 사용한 실험체들은 실험체정착길이/이론정착길이에 대한 실험내력/이론내력이 ACI 318-19 식은 1.30~1.48로 나타났으며, KDS-2021 식은 1.14~1.30로 평가되었다. 이를 볼 때, ACI 318-19 산정식이 보다 보수적으로 정착길이를 평가함으로써 더 큰 안전율을 가지고 있었다.

Use of Digital Educational Resources in the Training of Future Specialists in the EU Countries

  • Plakhotnik, Olga;Zlatnikov, Valentyn;Matviienko, Olena;Bezliudnyi, Oleksandr;Havrylenko, Anna;Yashchuk, Olena;Andrusyk, Pavlo
    • International Journal of Computer Science & Network Security
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    • 제22권10호
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    • pp.17-24
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    • 2022
  • The article proves that the main goal of informatization of higher education institutions in the EU countries is to improve the quality of education of future specialists by introducing digital educational resources into the education process. The main tasks of informatization of education are defined. Digital educational resources are interpreted as a set of data in digital form that is applicable for use in the learning process; it is an information source containing graphic, text, digital, speech, music, video, photo and other information aimed at implementing the goals and objectives of modern education; educational resources on the Internet, electronic textbooks, educational programs, electronic libraries, etc. The creation of digital educational resources is defined as one of the main directions of informatization of all forms and levels of Education. Types of digital educational resources by educational functions are considered. The factors that determine the effectiveness of using digital educational resources in the educational process are identified. The use of digital educational resources in the training of future specialists in the EU countries is considered in detail. European countries note that digital educational resources in professional use allow you to implement a fundamentally new approach to teaching and education, which is based on broad communication, free exchange of opinions, ideas, information of participants in a joint project, on a completely natural desire to learn new things, expand their horizons; is based on real research methods (scientific or creative laboratories), allowing you to learn the laws of nature, the basics of techniques, technology, social phenomena in their dynamics, in the process of solving vital problems, features of various types of creativity in the process of joint activities of a group of participants; promotes the acquisition by teachers of various related skills that can be very useful in their professional activities, including the skills of using computer equipment and various digital technologies.

마케팅 부서의 조절초점과 신제품 개발 창의성: 창의성 증진수단의 조절효과 (Marketing Organization's Regulatory Focus and NPD Creativity: The Moderating Role of Creativity Enhancement Tools)

  • 강성호;손정민
    • 유통과학연구
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    • 제14권7호
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    • pp.71-81
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    • 2016
  • Purpose - Because creativity, which is an intangible resource embedded within the company, can offer a competitive advantage, most companies have an interest in promoting creativity among their employees and division(e.g., marketing organization). Creativity renders a sustainable competitive advantage to a firm because it is a strategic resource that is valuable, flexible, rare, and imperfectly imitable or substitutable. Although most companies broadly recognize the importance of creativity, the methods for developing creativity remain elusive. Therefore, the present study investigates how to structure incentives to motivate employees to be more creative and how to develop tools to facilitate creativity. In detail, the present study aimed to examine the relationship between the regulatory focus of marketing organizations(e.g., promotion focus vs prevention focus) and creativity of marketing organizations. In addition, the present study set out to examine the moderating role of interaction of financial reward and creative training in addition to investigating the direct relationship between creativity and regulatory focus in New Product Development(NPD) context. Research design, data, and methodology - The data used to test the hypotheses are drawn from a survey of full time NPD project members(including project manager, designer, engineer, and marketer). The present study utilized data obtained mainly from a database compiled by the Korea Investors Service-Financial Analysis System which provides comprehensive corporate and financial information on firms listed on the Korea Stock Exchange. A study population comprising 1,000 South Korean firms was obtained from this database. We selected 864 firms from the database, and the firms have experiences of new product development project. We collected a total of 162 responses, for a 18.8% response rate. After we excluded 14 questionnaire because of incomplete responses, a total of 148 questionnaire remained(final response rate: 17.1%). Working with a sample of 148 responses in South Korea, hierarchical moderated regression is employed to test research hypotheses(

    The relationship between promotion focus and creativity of marketing organization,

    The relationship between prevention focus and creativity of marketing organization,

    The moderating effect of joint influences(interaction between financial rewards and creativity training) on the relationship between promotion focus creativity of marketing organization,

    The moderating effect of joint influences(interaction between financial rewards and creativity training) on the relationship between prevention focus creativity of marketing organization). SPSS 18.0 and AMOS software were used in the data analysis. Results - The empirical study confirmed that promotion focus of marketing organization is positively related to creativity of marketing organization. Also, prevention focus of marketing organization is positively affected to creativity of marketing organization. In addition, the interaction between financial rewards and creativity training moderated the relationship between regularity focus(e.g.), promotion focus vs prevention focus) and creativity of marketing organization. These results suggest that managers can improve the performances of their creative efforts by providing the use of financial rewards and creativity training in combination. Conclusion - Based on results of this study that examine the effects of regulatory focused creative efforts on creativity of marketing organization, promotion focus is helpful with marketing organizations to enhance their service innovation and performance. Prevention focused organization should allow monetary rewards and creativity training to increase their creativity for innovation of new products.

치과위생사의 수행업무에 대한 인식도 및 실태조사 (A study on the job awareness of dental hygienists and their job performance)

  • 심수현;황윤숙
    • 한국치위생학회지
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    • 제7권2호
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    • pp.153-166
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    • 2007
  • The job of dental hygienists is specialized, and they have to be capable of performing their primary duties including prevention of oral diseases, oral prophylaxis, and oral health education. To ensure their successful job performance, dentists should have an accurate understanding of their duties and need a change of mind-set about them. And there should be written legal and concrete regulations on the coverage of their work in order to let them boost their job performance with pride and a sense of responsibility. The purpose of this study was to examine the actual roles and job performance of dental hygienists in clinical field in an attempt to discuss the substantial job performance of dental hygienists and their job enlargement. It's basically meant to help enhance the efficiency and quality of medical services. The subjects in this study were 471 dental hygienists in dental clinics, dental hospitals, university hospitals and general hospitals across the nation, on whom a survey was conducted in person from March 2 to 25, 2005. The collected data were analyzed with SPSS Win 12.0 program, and the findings of the study were as follows: 1. The major jobs they currently performed included oral health education, hospital management, simple duties, extensive dental hygiene duties and joint treatment assistance. They hoped to continue to be responsible for oral health education, preventive treatment and extensive dental hygiene duties. 2. As for their current job by age, extensive dental hygiene duties, preventive treatment, joint treatment assistance, preserving treatment, prosthetic treatment and pediatric treatment were most conducted by the dental hygienists who were at the age of 26 to less than 31, and those who were at the age of 31 and up were most responsible for hospital management and simple duties. 3. As to job awareness by workplace, their workload was statistically significantly different according to their workplace. The hospital employees took care of more work than those in clinics. 4. Concerning job awareness by age, the younger dental hygienists suffered more role conflicts and were given a less free hand in work handling, the middle-aged group's job was uncertain. Legal regulations about the coverage of their work should be prepared in detail as a measure to stir up their responsible job performance and pride. In order to take advantage of experienced dental hygienists, their duties should be more differentiated and specialized, and their working conditions should be improved to boost their job satisfaction. That is, they should be given ample chances for promotion and serving as a middle manager and be given fair treatment according to their career. If their work is accurately darified and specialized based on career, it will boost the efficiency of dental treatment. Dental hygienists also should direct sustained efforts into self-development in order to become a skilled and professional oral health personnel.

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복합재 대차프레임의 볼트 체결부 내구성 향상을 위한 인서트 영향에 관한 연구 (Effect of the Insert Shape on the Improvement of Durability of Bolted Joints Applied to Composite Bogie Frames)

  • 김준환;신광복;김정석
    • 대한기계학회논문집A
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    • 제38권7호
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    • pp.765-770
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    • 2014
  • 본 논문에서는 복합재 대차프레임 볼트 체결부의 내구성 향상 방안에 대한 연구를 다루고 있다. 이를 위해, 인서트와 나사산 유무에 따른 3가지 경우를 고려하여 볼트 체결부에 대한 시험 및 해석을 통해 인서트 형태 및 유무에 미치는 영향을 평가하였다. 제안된 볼트 체결부의 구조 성능은 ASTM D5961에 의거한 시험을 통해 비교 평가하였다. 시험결과, 나사산이 없는 인서트를 갖는 볼트 체결부가 가장 적합한 것으로 확인되었다. 또한, 볼트 체결부를 고려한 복합재 대차프레임에 대한 구조 안전성 평가를 JIS E 4207에 의거하여 유한요소해석을 통해 평가하였다. 복합재 구조물은 Tsai-Wu 파손기준식에 의해 파손평가를 적용하였고, 볼트 체결부와 같은 금속재 구조물은 Von-Mises 파손기준식에 의해 평가하였다. 이때, 볼트 체결부의 경우에는 상세한 구조해석 결과 검토를 위해 서브모델링 기법을 적용하였다. 구조해석결과, 나사산이 없는 인서트가 적용된 볼트 체결부의 경우에는 볼트 체결부 주위의 복합재 구조물에 발생하는 Tsai-Wu 파손지수가 다른 경우에 비해 약 50% 감소하는 경향을 보였는데, 이는 나사선이 없는 인서트 형상이 복합재 대차프레임 볼트 체결부의 내구성을 향상시킬 수 있을 것으로 판단된다.

해상 프리캐스트 콘크리트 부유체 모듈 가접합을 위한 마이크로 실리카 혼입 수중용 에폭시 접합 성능 검토 : Part 2 - 구조 접합 성능 평가 (Micro-silica Mixed Aqua-epoxy for Concrete Module Connection in Water : Part 2 - Structural Application and Evaluation)

  • 최진원;유영준;정연주;권성준;김장호
    • 콘크리트학회논문집
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    • 제27권1호
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    • pp.29-35
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    • 2015
  • 최근 연구되고 있는 해상 초대형 부유 콘크리트 구조물의 제작은 현장 타설이 어렵다는 단점이 있으므로 프리캐스트 콘크리트로 제작한 모듈을 수상에서 인양 후 프리스트레스력으로 접합 및 제작하는 것을 목표로 한다. 그러나 해상 환경에서 발생하는 다양한 하중 및 예상되는 상부 구조물에 의한 하중을 고려하였을 때, 프리스트레스력으로 접합되는 콘크리트 모듈 간의 접합부의 안정적인 거동 및 성능이 요구된다. 이에 프리스트레스력이 적용되기 전 가접합에 수중용 에폭시를 이용한 접합 방법이 고려되고 있는데, 수중용 에폭시는 고점성의 재료로서 내부에 공극이 발생하기 쉽다. 이를 해결하기 위하여 마이크로 실리카를 혼입하여 공극을 감소시킨 수중용 에폭시를 이용하여 콘크리트 부유체의 접하 거동에 대한 평가가 요구된다. 그러므로 이번 연구에서는 마이크로 실리카를 혼입한 수중용 에폭시를 이용하여 가접합하고 프리스트레싱을 적용한 시험체를 제작하여 성능을 평가하였다. 마이크로 실리카를 혼입한 수중용 에폭시로 접합된 콘크리트 모듈은 프리스트레싱만을 적용한 시험체에 비하여 균열 발생 및 응력 집중 현상이 완화되었으며, 최대 하중 및 변위는 일체형 RC 시험체에 비하여 10% 미만의 감소율을 나타내어 모듈형 콘크리트 부유체의 수상 접합을 위한 안정적인 접합재료로 사용 가능할 것으로 보인다.