• Title, Summary, Keyword: Micro Mechanical Materials Modeling 방법

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Nonlinear Viscoelastic Analysis of Reticulated Spatial Truss Composed of Composite Materials (복합재료 그물형 공간 트러스의 점탄성적 비선형 해석)

  • Han, Sung Cheon;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.13 no.6
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    • pp.661-672
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    • 2001
  • The present study is concerned with the arc-length method in the investigation of the large deflection behavior of spatial structures with composite materials. This study should be able to trace the main equilibrium path by automatically varying the arc-length size of individual solution steps with the variation of the curvature of the nonlinear equilibrium path. A quasi-elastic method is used for the solution for viscoelastic analysis of the reticulated spatial structures. Elastic modulus of composite materials is defined by micro mechanical materials modeling method and nonlinear equilibrium path is traced with various load types. To demonstrate the effectiveness of the present strategies, numerical examples of reticulated spatial truss is given and compared with solutions using other methods.

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A study on machining method about molybdenum alloy micro fixing part for TEM precision specimen. (TEM 정밀 시편 제작용 몰리브덴 합금 미세 고정 부품의 제작을 위한 절삭 가공 방법에 관한 연구)

  • Kim, Ki-Beom;Lee, Chang-Woo;Lee, Hae-Jin;Ham, Min-Ji;Kim, Gun-Hee
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.11 no.3
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    • pp.19-24
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    • 2017
  • In these days, increase requirement of TEM (Transmission Electro Microscope) in not only scientific field but also industrial field. Because TEM can measure inner-structure of specimen a variety of materials like metal, bio. etc. When use TEM, specimen should be thin about 50nm. So making for thin specimen, use Ion milling device that include specimen holder. The holder generally made of Aluminium Aluminium holder is worn away easily. For this reason, using time of ion milling with aluminum holder is too short. To solve the problem, we replace aluminium holer to molybdenum alloy holder. In this paper, we design molybdenum alloy holer for CAM and modify CAD modeling for effective machining process. So we array a specimen 3 by 4 and setup orientation for one-shot machining process. Next we make a CAM program for machining. we making a decision two machining strategy that chose condition of tool-path method, step-down, step-over. etc. And then conduct machining using CNC milling machining center. To make clear difference between case.1 and case.2, we fixed machining conditions like feed-rate, main spindle rpm, etc. After machining, we confirm the condition of workpiece and analysis the problems case by case. Finally, case.2 work piece that superior than case.1 cutting with WEDM because that method can not ant mechanical effect on workpiece.