• Title/Summary/Keyword: Mechanical engineers

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Impact Analysis of BIM Spread on Mechanical Design Process Based on Consciousness Survey among Japanese Mechanical Engineers

  • Hiyama, Kyosuke;Diao, Yunting;Kato, Shisuke;Koganei, Makoto
    • International Journal of High-Rise Buildings
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    • v.2 no.2
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    • pp.97-104
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    • 2013
  • Recently, the demand for Building Information Modeling (BIM) construction drawings and specifications has increased rapidly. Many countries have also started to implement BIM. The BIM implementation can change the design flow of buildings including high-rise buildings. Against this background, many companies are focusing on the development of BIM software. BIM involves a three-dimensional CAD program that can examine the placement of ductwork and machinery. It significantly increases the efficiency of a mechanical design through data unification using standard Industry Foundation Classes (IFC). In addition, BIM functions as a database to simplify the use of simulation technology for designing air-conditioning systems. To further develop BIM, it is important to know the expectations of mechanical engineers who will become frequent users of BIM in the future. A survey was conducted among Japanese mechanical engineers using a questionnaire to analyze the expectations of mechanical design using BIM. The results show that many respondents strongly recognize BIM as a three-dimensional CAD program. However they also expect that BIM can help the optimization of their design works and enhance design functionality by running simulations utilizing BIM.

Application of the Concept of a sSnsitivity Linkage for the Analysis of Mechanical Error in 4-Bar Mechanism (민감도 해석기구를 이용한 4절기구의 기계적 오차해석)

  • Sin, Jae-Kyun;Choi, Hong-Suck
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.5
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    • pp.1508-1515
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    • 1996
  • The method of utilizing sensitivity linkages for the analysis of mechanical errors are proposed. As sources of the mechanical error, tolerances in the link length and clearances in thejoints are considered. It is demonstrated that the problem of calculating mechanical errors of a 4-bar mechanism can be transformed into a problem of conventeional velocity analysis of a sensitivity linkage. As a result of the present study, it is found and proved that the mechanical error of the output angle in the 4-Bar mechaism is represented as a simple harmonic function with respect to the relative position of the pin on the clearance circle. Also the vector representing the mechanical error of a coupler point makes, in general, an ellipse as the relative angle varies on the clearance circle. With these results we can better identify the characteristic of the mechanical errors in linkages.

Analysis of Mechanical Stress Due to Magnetic Force and Thermal Expansion in Brsushless Motor (브러시레스 전동기에서 전자기적 가진력 및 열에 의한 기계적 음력해석)

  • Ha, Gyeong-Ho;Hong, Jeong-Pyo;Lee, Geun-Ho
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.5
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    • pp.221-227
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    • 2002
  • This paper deals with the mechanical stress analysis due to electromagnetic forces and the optimal design of the link considering the stress. The link in Interior Permanent Magnet Brushless Motor(IPM) have influence on both mechanical and magnetic performance. The decrease of the link thickness serves to improve the torque, whereas this decreases the strength of link. Therefore, it is necessary to determine the appropriate link thickness considering electromagnetic forces and thermal expansion. The effects of the variation of link thickness on the mechanical stress and the electromagnetic performance are analyzed by the structural and electromagnetic Finite Element Method. In addition, the mechanical structure design of the link is performed to reinforce the mechanical strength against magnetic forces while preserving a food magnetic torque.

Study on tolerance and reliability analysis of mechanical systems with uncertainty (불확정성을 고려한 기계 시스템의 공차해석 및 신뢰도 해석에 관한 연구)

  • Choe, Jin-Ho;Lee, Se-Jeong;Choe, Dong-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.1
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    • pp.215-226
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    • 1998
  • This paper addresses an analytical approach to tolerance and reliability analysis of mechanical systems with uncertainty. Many mechanical systems consist of links and lubricated joints. The mobility method is applied to consider lubrication effects and the clearance vector model is used to stochastically define a mechanism for tolerance and reliability analysis. To show the validity of the proposed method, a four-bar path generator and a slider-crank mechanism are considered. The results obtained by applying the proposed method are compared with those by Monte-Carlo simulation.

Effect of Chemical Mechanical Cleaning(CMC) on Particle Removal in Post-Cu CMP Cleaning (구리 CMP 후 연마입자 제거에 화학 기계적 세정의 효과)

  • Kim, Young-Min;Cho, Han-Chul;Jeong, Hae-Do
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.10
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    • pp.1023-1028
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    • 2009
  • Cleaning is required following CMP (chemical mechanical planarization) to remove particles. The minimization of particle residue is required with each successive technology generation, and the cleaning of wafers becomes more complicated. In copper damascene process for interconnection structure, it utilizes 2-step CMP consists of Cu and barrier CMP. Such a 2-steps CMP process leaves a lot of abrasive particles on the wafer surface, cleaning is required to remove abrasive particles. In this study, the chemical mechanical cleaning(CMC) is performed various conditions as a cleaning process. The CMC process combined mechanical cleaning by friction between a wafer and a pad and chemical cleaning by CMC solution consists of tetramethyl ammonium hydroxide (TMAH) / benzotriazole (BTA). This paper studies the removal of abrasive on the Cu wafer and the cleaning efficiency of CMC process.

A Study on the Decision Process of the Length Dimension of a Mechanical System (기계 시스템의 길이제원 결정과정에 관한 연구)

  • Cheon, G.J;Lee, J.H;Han, D.C
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.5
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    • pp.800-808
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    • 1997
  • Decision process for length dimension in the mechanical system design process has been studied with a washing machine transmission as a model. The results are, (i) the length dimensions of the non-shaft elements are independent of other elements, (ii) the length dimensions of the shaft elements are dependent on the dimensions of the non-shaft elements located inside and outside of that elements, (iii) the length dimensions of the inner shaft elements are dependent on those of the outer shaft elements located parallel, (iv) the length dimensions of the shaft elements located serial are independent of each other.

Design of an Intelligent Polymer-Matrix-Composite Using Shape Memory Alloy (형상기억합금을 이용한 지능형 고분자 복합재료의 설계)

  • Jeong, Tae-Heon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.10
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    • pp.1609-1618
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    • 1997
  • Thermo-mechanical behaviors of polymer matrix composite(PMC) with continuous TiNi fiber are studied using theoretical analysis with 1-D analytical model and numerical analysis with 2-D multi-fiber finite element(FE) model. It is found that both compressive stress in matrix and tensile stress in TiNi fiber are the source of strengthening mechanisms and thermo-mechanical coupling. Thermal expansion of continuous TiNi fiber reinforced PMC has been compared with various mechanical behaviors as a function of fiber volume fraction, degree of pre-strain and modulus ratio between TiNi fiber and polymer matrix. Based on the concept of so-called shape memory composite(SMC) with a permanent shape memory effect, the critical modulus ratio is determined to obtain a smart composite with no or minimum thermal deformation. The critical modulus ratio should be a major factor for design and manufacturing of SMC.

A Study on the Optimum Joining Condition in a Mechanical Press Joint (기계적 프레스 접합의 최적접합조건에 관한 연구)

  • Lee, Yong-Bok;Kim, Tae-Yun;Jeong, Jin-Seong;Choe, Ji-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.752-760
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    • 2000
  • Mechanical press joining has been used in sheet metal joining processes because of its simple process and possibility of joining dissimilar metals, such as steel and aluminum. The strength of mechanical press joining varies with joining conditions. The optimum joining conditions considering tensile-shear and peel-tension strength have to be established to assure the reliability in the joining strength. Therefore, optimization of joining conditions has been investigated for improving joining strength of sheet metal. It is possible to obtain optimum strength from improvement on the joining strength of peel-tension mechanical press joint under multiaxial stress states.