• Title/Summary/Keyword: elastic shape

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Finite Element Analysis and Optimal Design of Shape Memory Composite Material Stents using Taguchi Method (다구찌 방법을 이용한 형상기억 복합재료 스텐트 유한요소 해석 및 최적설계)

  • Young Bin Kim;Suji Kim;Heechan Song;Heoung-Jae Chun
    • Composites Research
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    • v.37 no.4
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    • pp.301-309
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    • 2024
  • Shape memory stents are used for treating vascular conditions like myocardial infarction, angina, and arteriosclerosis through their shape memory behavior. These stents are inserted into blood vessels to expand them, and their performance in terms of flexibility, elastic recovery, and deformation is influenced by their design. In this study, parameters affecting stent structural design were analyzed using Taguchi method, aiming to design structures that consider flexibility, elastic recovery, and deformation. Reflecting the actual conditions faced by stents, ISO standards were incorporated, and finite element analysis was conducted, considering shape memory composite material properties obtained from tensile tests, specifically hyperealstic properties. Ultimately, statistical significance of stent structural design was evaluated through ANOVA (Analysis of Variance), and an improved optimal design model compared to the existing one was proposed.

Finite Elements Adding and Removing Method for Two-Dimensional Shape Optimal Design

  • Lim, Kyoung-Ho;John W. Bull;Kim, Hyun-Kang
    • Journal of Mechanical Science and Technology
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    • v.15 no.4
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    • pp.413-421
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    • 2001
  • A simple procedure to add and remove material simultaneously along the boundary is developed to optimize the shape of a two dimensional elastic problems and to minimize the maximum von Mises stress. The results for the two dimensional infinite plate with a hole, are close to the theoretical results of an elliptical boundary and the stress concentration is reduced by half for the fillet problem. The proposed shape optimization method, when compared with existing derivative based shape optimization methods has many features such as simplicity, applicability, flexibility, computational efficiency and a much better control on stresses on the design boundary.

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Novel Mesh Regeneration Method Using the Structural Deformation Analysis for 3D Shape Optimization of Electromagnetic Device (전자소자의 3차원 형상최적화를 위한 구조변형 해석을 이용한 새로운 요소망 변형법)

  • Yao Yingying;Jae Seop Ryu;Chang Seop Koh;Dexin Xie
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.6
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    • pp.247-253
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    • 2003
  • A novel finite element mesh regeneration method is presented for 3D shape optimization of electromagnetic devices. The method has its theoretical basis in the structural deformation of an elastic body. When the shape of the electromagnetic devices changes during the optimization process, a proper 3D finite element mesh can be easily obtained using the method from the initial mesh. For real engineering problems, the method guarantees a smooth shape with proper mesh quality, and maintains the same mesh topology as the initial mesh. Application of the optimum design of an electromagnetic shielding plate shows the effectiveness of the presented method.

A Study on Cyclic Deformation and Fatigue Phenomenon of Shape Memory Alloy (형상기억합금의 반복변형특성과 피로현상에 관한 연구)

  • 박영철;오세욱;허정원;이명렬
    • Journal of Ocean Engineering and Technology
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    • v.6 no.1
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    • pp.87-95
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    • 1992
  • Recently, the robot actuator worked by the driving recovery-force of the thermo elastic martensitic transformation of shape memory alloys(SMA) has been studied. In general, such a SMA actuator necessitates a number of cyclic repeated motion, so that the investigation of gradual decrease of recovery force with repeated motion cycle as well as the prevention of such a degradation of shape memory effect(SME) are very important for the actual use of a robot actuator. However, such research and discussions about the degradation of SME are very few up to the present. Therefore, in this study, the characteristics of the cyclic deformation and degradation of SME of Ti-Ni alloy would be investigated and discussed in detail by current heat type fatigue tester, which is a newly designed fatigue tester by author. In addition, we will establish a new design concept for robot actuator from these result.

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Optimal shape design of contact systems

  • Mahmoud, F.F.;El-Shafei, A.G.;Al-Saeed, M.M.
    • Structural Engineering and Mechanics
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    • v.24 no.2
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    • pp.155-180
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    • 2006
  • Many applications in mechanical design involve elastic bodies coming into contact under the action of the applied load. The distribution of the contact pressure throughout the contact interface plays an important role in the performance of the contact system. In many applications, it is desirable to minimize the maximum contact pressure or to have an approximately uniform contact pressure distribution. Such requirements can be attained through a proper design of the initial surfaces of the contacting bodies. This problem involves a combination of two disciplines, contact mechanics and shape optimization. Therefore, the objective of the present paper is to develop an integrated procedure capable of evaluating the optimal shape of contacting bodies. The adaptive incremental convex programming method is adopted to solve the contact problem, while the augmented Lagrange multiplier method is used to control the shape optimization procedure. Further, to accommodate the manufacturing requirements, surface parameterization is considered. The proposed procedure is applied to a couple of problems, with different geometry and boundary conditions, to demonstrate the efficiency and versatility of the proposed procedure.

Fatigue Characterization of NiTiCu Shape Memory Alloys (NiTiCu 형상기억합금의 피로특성)

  • Han, Ji-Won;Park, Sung Bum
    • Journal of the Korean Society of Safety
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    • v.29 no.4
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    • pp.28-33
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    • 2014
  • Recently, the actuator worked by the driving recovery-force of the thermo elastic martensitic transformation of shape memory alloys(SMA) has been studied. This paper presents a study on the fatigue life of shape memory alloy (SMA) actuators undergoing thermally induced martensitic phase transformation under various stress levels. shape memory recoverable stress and strain of Ti-44.5at.%Ni-8at.%Cu alloys were by means of constant temperature tensile tests. Differential scanning calorimetry (DSC) was employed in order to investigate the transformation characteristics of the alloy before the tests. the results were summarized as follows. The martensite inducing stress incerased with the increasing of the Cu-contents. The fatigue life decreased with the increasing of the test load and the Cu-content. The data acquired will be very useful during the design process of an SMA NiTiCu element as a functional part of an actuator.

Distribution of Welding Residual Stresses in Laser Welds with the Nail-head shape

  • Kim, Y.P.;Joo, S.M.;Bang, H.S.
    • International Journal of Korean Welding Society
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    • v.3 no.1
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    • pp.17-22
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    • 2003
  • During the laser welding, weldments are suddenly heated and cooled by laser beam of high density energy. This phenomenon gives an occasion to complex welding residual stresses, which have a great influence on structural instability, in laser welds. However, relevant researches on this field are not sufficient until now and residual stress measurements have experimental and practical limitations. From these reasons, a numerical simulation may be attractive in order to solve the residual stress problem. For clarifying the distribution of heat and welding residual stresses in laser welds with the nail-head shape, authors conduct the finite element analysis (two-dimensional unstationary heat conduction & thermal elastic and plastic analysis). From the results, we can confirm the stress concentration occurs at the place of melting line shape changed in laser welds with the nail-head shape.

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Transverse earthquake-induced forces in continuous bridges

  • Armouti, Nazzal S.
    • Structural Engineering and Mechanics
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    • v.14 no.6
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    • pp.733-738
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    • 2002
  • A simplified rational method is developed to evaluate transverse earthquake-induced forces in continuous bridges. This method models the bridge as a beam on elastic foundation, and assumes a sinusoidal curve for both vibration mode shape and deflected shape in the transverse direction. The principle of minimum total potential is used to calculate the displacements and the earthquake-induced forces in the transverse direction. This method is concise and easy to apply, and hence, offers an attractive alternative to a lengthy and time consuming three dimensional modeling of the bridge as given by AASHTO under its Single Mode Spectral Analysis Method.

A Numeric Modelling Technique for the Shape Development of Fatigue Crack (피로 균열 형상 진전의 수치 모델링 기법에 관한 연구)

  • Han, Moon-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.2 s.95
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    • pp.225-233
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    • 1999
  • This paper describes a versatile finite element technique which has been used to investigate of wide range of structural defects of practical importance. The procedure automatically remeshes the three-dimensional finite element model during the stages of crack growth. Problems analyzed to date include the surface cracks in leak-before-break situations, the development of quarter-elliptical corner defects, planar semi-elliptical surface defects and the fatigue growth of defects.

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Flexural Vibration of a Rectangular Plate with Orthotropically and Harmonically Varying Material Properties (재질분포가 직교이방 조화함수로 변하는 사각 평판의 굽힘 진동 해석)

  • 김진오;문병환
    • Journal of KSNVE
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    • v.11 no.2
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    • pp.323-328
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    • 2001
  • The paper describes a theoretical study on the flexural vibration of an elastic rectangular plate with periodically nonuniform material properties. The approximate solution of the natural frequency and mode shape has been obtained using the perturbation technique for sinusoidal modulation of the flexural rigidity and mass density. It has been shown that distributed modes exist in the plate which Is a two-dimensional model of the flat panel speaker.

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