• Title/Summary/Keyword: S-shape function

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Yield function of the orthotropic material considering the crystallographic texture

  • Erisov, Yaroslav A.;Grechnikov, Fedor V.;Surudin, Sergei V.
    • Structural Engineering and Mechanics
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    • v.58 no.4
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    • pp.677-687
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    • 2016
  • On the basis of the energy approach it is reported a development of the yield function and the constitutive equations for the orthotropic material with consideration of the crystal lattice constants and parameters of the crystallographic texture for the general stress state. For practical use in sheet metal forming analysis it is considered different loading scenarios: plane stress and plane strain states. Using the proposed yield function, the influence of single ideal components on the shape of yield surface was analyzed. The six texture components investigated here were cube, Goss, copper, brass, S and rotated cube, as these components are typically observed in rolled sheets from FCC alloys.

Economies of Scale in Multiproduct Firms;Evidence from Air Transport Industry (항공운송산업의 비용분석을 통한 규모의 경제성 추정;초월대수(Translog)비용함수와 푸리에(Fourier) 신축함수 비교 분석을 중심으로)

  • Kim, Je-Chul;Huh, Seok-Min;Lee, Dong-Hui;Lee, Young-Soo
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.14 no.4
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    • pp.38-47
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    • 2006
  • This study analyzes the expense structure of the air transport industry, based on the cost and income data of 18 major airlines, estimates the economic effectiveness of scale and conducts comparative analysis. As for the method of analysis, Translog cost function and the Fourier flexible function were used. The result showed that big companies had the economy of scale based on the Translog cost function, while the Fourier flexible function led to a estimation that expanding the input is not recommended, for the expansion of scale entails the poor economy of scale. It can be presumed that the economy of scale was estimated according to the U shape of the Translog cost function in the given data. On the other hand, the Fourier flexible cost function approaches the unknown function, as it is a Fourier series, and correctly infers the economy of scale based on the analyzed data. As for the flag carrier's economy of scale, it was inferred that the economy of scale existed by any of two functions. Therefore, the conclusion was that further expanding the scale will not cause any problem.

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A comprehensive analysis on the discretization method of the equation of motion in piezoelectrically actuated microbeams

  • Zamanian, M.;Rezaei, H.;Hadilu, M.;Hosseini, S.A.A.
    • Smart Structures and Systems
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    • v.16 no.5
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    • pp.891-918
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    • 2015
  • In many of microdevices a part of a microbeam is covered by a piezoelectric layer. Depend on the application a DC or AC voltage is applied between upper and lower side of the piezoelectric layer. A common method in many of previous works for evaluating the response of these structures is discretizing by Galerkin method. In these works often single mode shape of a uniform microbeam i.e. the microbeam without piezoelectric layer has been used as comparison function, and so the convergence of the solution has not been verified. In this paper the Galerkin method is used for discretization, and a comprehensive analysis on the convergence of solution of equation that is discretized using this comparison function is studied for both clamped-clamped and clamped-free microbeams. The static and dynamic solution resulted from Galerkin method is compared to the modal expansion solution. In addition the static solution is compared to an exact solution. It is denoted that the required numbers of uniform microbeam mode shapes for convergence of static solution due to DC voltage depends on the position and thickness of deposited piezoelectric layer. It is shown that when the clamped-clamped microbeam is coated symmetrically by piezoelectric layer, then the convergence for static solution may be obtained using only first mode. This result is valid for clamped-free case when it is covered by piezoelectric layer from left clamped side to the right. It is shown that when voltage is AC then the number of required uniform microbeam shape mode for convergence is much more than the number of required mode in modal expansion due to the dynamic effect of piezoelectric layer. This difference increases by increasing the piezoelectric thickness, the closeness of the excitation frequency to natural frequency and decreasing the damping coefficient. This condition is often indefeasible in microresonator system. It is concluded that discreitizing the equation of motion using one mode shape of uniform microbeam as comparison function in many of previous works causes considerable errors.

Characteristics of the Body Shape of Korean Woman Farmers by Crops (주 재배 작목별 한국 여성 농업인 체형 특성)

  • Baek, Yoon-Jeong;Lee, Kyung-Suk
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.10
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    • pp.1584-1594
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    • 2008
  • This study was to research the characteristics of the body shape of Korean woman farmers by the major crops. Four hundred ninety-five Korean woman farmers from 9 different area such as Kumi, Damyang, Iksan, Injae, Chungju, Choongju, Haman, Whasung, and Whasoon volunteered for this study. Their major crops were the rice, the pepper, the water melon, the strawberry, the wild rocambole, the sweet persimmon, the grapes, the mushroom, and the chrysanthemums. Twelve body angles were measured from archived the somatotype photographs of the front, the side, and the back. Questionnaires of SF-36 and the farmer's symptom, and the farm-work related movements were surveyed. The results were as follows; 1. Farmers had lower health levels in physical role limit, pain, vitality, and physical function than other occupational workers. 2. Most farmers acted the high-risk ergonomics motions when they worked in the farm. 3. There were significantly different on the both shoulder angles, the hip tangential line slope, the hip breadth angel, in frontal ankle-knee angle, the bending back angle, the dropping breast slope, the abdominis media angle, under the abdominis media angle, the glutea angle, under the glutea angle, and the sideward knee angle(p<.05). 4. Farmers cultivating the low plants such as the water melon, the strawberry, and the wild rocambole showed more banded vertebralis and side knee angles. Farmers cultivating the red pepper showed the dropping the left shoulder and O shape legs. Farmers cultivating the fruit trees such as the sweet persimmon and the grapes showed the less banded side knee angles than other farmer groups. 5. On comparing the same age, farmers showed the older's body shape in earlier and much more than the old living in the city.

Forced vibration of surface foundation on multi-layered half space

  • Chen, Lin
    • Structural Engineering and Mechanics
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    • v.54 no.4
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    • pp.623-648
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    • 2015
  • A numerical approach is presented for the analysis of the forced vibration of a rigid surface foundation with arbitrary shape. In the analysis, the foundation is discretized into a number of sub squaree-lements. The dynamic response within each sub-element is described by the Green's function, which is obtained by the Fourier-Bessel transform and Precise Integration Method (PIM). Incorporating the displacement boundary condition and force equilibrium of the foundation, it obtains a system of linear algebraic equation in terms of the contact forces within each sub-element. Solving the equation leads to the desired dynamic impedance functions of the foundation. Numerical results are obtained for foundation not only with simple geometrical configurations, such as rectangular and circular foundation, but also the case of irregularly shaped foundation. Several comparisons between the proposed approach and other methods are made. Very good agreement is reached. Also, parametric studies are carried out on the dynamic response of foundation. Addressed in this study are the effects of Poisson's ratio, material damping and contact condition of soil-foundation interface. Several conclusions are drawn the significance of the factors.

A Study on Optimization of Crankshaft in Diesel Engine (디이젤 엔진의 크랭크축 최적설계에 관한 연구)

  • Cho, S.B.;Ahn, S.H.;Yoo, H.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.5
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    • pp.10-16
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    • 1995
  • In this study, the optimum design is carried out upon the crankshaft of in-line 6-cylinder internal combustion diesel engine with the mechanical analysis for the layout design, which is standard calculation whose process contains quadratic curve fitting method and quasi newton method about cost function, design variables and constraint conditions, Without finite element analysis, this process in wich mechanical analysis is performed upon the most critical part in crankshaft gives necessary and satisfied output in layout design and saves time and cost in developing a new diesel engine. In this study, also, the 3-dimensional finite element method is used in confirming the standard calculation for the optimization of crankshaft and the shape optimization in crankweb is obtained.

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Line-edge Detection using 2-D Wavelet Function in Degraded Image by AWGN (AWGN에 훼손된 영상에서 2-D 웨이브렛 함수를 이용한 라인-에지 검출)

  • 배상범;김남호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.3
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    • pp.748-753
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    • 2004
  • Edge includes variety of information about image's location and shape etc. So a lot of researches for detecting those edges have been continuing even now and at the early stage of the research, edge detection operators searched neighborhood pixels and used relation among pixels. However, these methods do not have excellent performance in the image which exists noise and can not detect edges selectively. For this reason, in this paper we detected image's line-edge element from degraded image by AWGN (additive white gaussian noise) with wavelet function which is independent of line's width.

Morphological Changes of Golgi Apparatus during Spermiogenesis in the Long-fingered Bat, Miniopterus schreibersi fuliginosus (한국산 긴날개박쥐, Miniopterus schreibersi fuliginosus의 정자변태과정 중 Golgi Apparatus의 형태적 변화)

  • 손성원
    • Development and Reproduction
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    • v.1 no.2
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    • pp.133-139
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    • 1997
  • To study the function and structure of Golgi apparatus in the spermiogenesis of long-fingered bat (Miniopterus schreibersi fuliginosus), the testis obtained from adult bat was treated with the prolonged osmification or fixed with ferrocyanide reduced osmium. golgi apparatus was oval shape in early Golgi phase, and was composed of cortex and medullar enclosing acrosome in mid Golgi phase. The vesicles of crescent shape Golgi apparatus were closed or fused with small or large vesicles at the periphery of acrosome. Golgi apparatus moved behing the acrosome face in cap phase, but the Golgi apparatus was still active. According to this, Golgi apparatus appears to be involved in the formation of acrosome and sperm tail. Transfer of materials from Golgi to acrosme seems to be carried out not only by fusion of large vesicles with acrosomal vesicles but also by detachment of coated vesicle from various cisternae of Golgi fusing with acrosomal vesicle.

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ADJOINT METHOD FOR CONTROLLED CAVITATION INVERSE NOZZLE DESIGN

  • Petropoulou, S.;Gavaises, M.;Theodorakakos, A.
    • International Journal of Automotive Technology
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    • v.7 no.3
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    • pp.283-288
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    • 2006
  • A mathematical methodology is proposed for designing nozzle hole shapes producing controlled geometric cavitation. The proposed methodology uses an unstructured RANS flow solver, with the ability to compute sensitivity derivatives via an adjoint algorithm. The adjoint formulation for the N-S equations is presented while variation of the turbulence viscosity is not taken into account during the geometry modifications. The sensitivities are calculated in a mode independently of the shape parameterisation. The method is used to develop and evaluate conceptual shapes for nozzle hole cavitation reduction. The localized region at the hole inlet producing cavitation, is parameterised using its radius of curvature, while a cost function is formulated to eliminate the negative pressures present at this location. Sensitivity derivatives are used to assess the dependence of the localized region on the minimum pressure, and to drive the geometry to the targeted shape. The results show that the computer model can provide nozzle hole entry shapes that produce predefined flow characteristics, and thus can be used as an inverse design tool for nozzle hole cavitation control.

Subthreshold Characteristics of Double Gate MOSFET for Gaussian Function Distribution (도핑분포함수의 형태에 따른 DGMOSFET의 문턱전압이하특성)

  • Jung, Hak-Kee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.6
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    • pp.1260-1265
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    • 2012
  • This paper have presented the change for subthreshold characteristics for double gate(DG) MOSFET based on scaling theory and the shape of Gaussian function. To obtain the analytical solution of Poisson's equation, Gaussian function been used as carrier distribution and consequently potential distributions have been analyzed closely for experimental results, and the subthreshold characteristics have been analyzed for the shape parameters of Gaussian function such as projected range and standard projected deviation. Since this potential model has been verified in the previous papers, we have used this model to analyze the subthreshold chatacteristics. The scaling theory is to sustain constant outputs for the change of device parameters. As a result to apply the scaling theory for DGMOSFET, we know the subthreshold characteristics have been greatly changed, and the change of threshold voltage is bigger relatively.