• Title/Summary/Keyword: displacement components

Search Result 521, Processing Time 0.027 seconds

Interactions in a transversely isotropic new modified couple stress thermoelastic thick circular plate with two temperature theory

  • Parveen Lata;Harpreet Kaur
    • Coupled systems mechanics
    • /
    • v.12 no.3
    • /
    • pp.261-276
    • /
    • 2023
  • This article is an application of new modified couple stress thermoelasticity without energy dissipation in association with two-temperature theory. The upper and lower surfaces of the plate are subjected to an axisymmetric heat supply. The solution is found by using Laplace and Hankel transform techniques. The analytical expressions of displacement components, conductive temperature, stress components and couple stress are computed in transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerically simulated results are depicted graphically. The effect of two temperature is shown on the various components.

Study on Structural Safety of Car Securing Equipment of Coastal Carferry: Part II Assessment of Lashing Safety according to Acceleration Prediction Approaches (국내 연안 카페리 차량 고박 장치 안전성에 관한 연구: 제2부 가속도 예측 방법에 따른 고박 안전도 비교 연구)

  • Choung, Joonmo;Jo, Huisang;Lee, Kyunghoon;Lee, Young Woo
    • Journal of Ocean Engineering and Technology
    • /
    • v.30 no.6
    • /
    • pp.451-457
    • /
    • 2016
  • For a carferry with a displacement of 1,633 tonf, a seakeeping analysis-based direct load approach (DLA) was used in Part I of these series, where the final deliverable was the long-term probabilistic acceleration components. In Part II of these series, the tangential acceleration components are explained based on two approaches: a standard called the IMO CSS code and simple formulas with the probable maximum roll and pitch rotations. The subsequent tangential acceleration-induced external force components are also introduced for these two approaches. The lashing strength components were selected from the IMO CSS code. It was assumed that two different vehicles (a car and a truck) were stowed at the most distant locations on the main deck to assume the largest tangential acceleration components and were secured with four steel wires with longitudinal and transverse lashing angles of $45^{\circ}$. Four cases were considered, with different methods for predicting the acceleration components and different tools for the external loads and lashing strengths involved: cases Rule-LS (rule-based maximum probable roll and pitch angles for predicting the acceleration components in conjunction with LashingSafety), DLA-LS (seakeeping-based long-term acceleration components with LashingSafety), CSS-LC (IMO CSS code-based acceleration components using LashCon), and CSS-LS (IMO CSS code-based acceleration components using LashingSafety). In terms of the acceleration and external force components, the CSS-LC and CSS-LS results are more than two times the results of Rule-LS. Thus, when the external forces and lashing strengths are evaluated using CSS-LC and CSS-LS, the truck needs more lashing wires, while Rule-LS and DLA-LS predict that the present lashing configuration is on the safe side.

Development of the Dynamic Photoelastic Hybrid Method for Propagating Interfacial Crack of Isotropic/Orthotropic Bi-materials (등방성/직교이방성 이종재료의 진전 계면균열에 대한 동적 광탄성 실험 하이브리드 법 개발)

  • Hwang, Jae-Seok;Sin, Dong-Cheol;Kim, Tae-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.7
    • /
    • pp.1055-1063
    • /
    • 2001
  • When the interfacial crack of isotropic/orthotropic bi-materials is propagated with constant velocity along the interface, stress and displacement components are derived in this research. The dynamic photoelastic experimental hybrid method for the bimaterial is introduced. It is assured that stress components and dynamic photoelastic hybrid developed in this research are valid. Separating method of stress components is introduced from only dynamic photoelastic fringe patterns. Crack propagating velocity of interfacial crack is 69∼71% of Rayleigh wave velocity of epoxy resin. The near-field stress components of bonded interface of bimaterial are similar with those of pure isotopic material and two dissimilar isotropic bimaterials under static or dynamic loading, but very near-field stress components of bonded interface of bimaterial are different from those.

Spectral Analysis for Non-Invasive Total Hemoglobin Measurement in the Region from 400 to 2500nm (총헤모글로빈 농도를 비침습적으로 측정하기 위한 400-2500nm 대역의 흡수 스펙트럼 분석)

  • Jeon, Kye-Jin;Kim, Yoen-Joo;Kim, Su-Jin;Kim, Hong-Sig;Yoon, Gil-Won
    • Journal of Sensor Science and Technology
    • /
    • v.10 no.6
    • /
    • pp.273-278
    • /
    • 2001
  • Absorption spectra of blood components have been measured for the purpose of predicting the total hemoglobin concentration. We obtained absorption spectra of major blood components from the visible to near-infrared of $400{\sim}2500nm$ region. In the near-infrared, water is the main absorbing constituent. The amount of water in the sample cell varies depending on the volume of solute concentration(water displacement). We acquired water-compensated spectra by considering the variation of water volume depending on the variation of analyze concentration. Those spectra show inherent absorption peaks of analyzes and linearity with respect to concentration. We selected wavelengths for non-invasive measurement of hemoglobin concentration considering the scattering effect of tissue and the interference of other blood components.

  • PDF

A computational shear displacement model for vibrational analysis of functionally graded beams with porosities

  • Atmane, Hassen Ait;Tounsi, Abdelouahed;Bernard, Fabrice;Mahmoud, S.R.
    • Steel and Composite Structures
    • /
    • v.19 no.2
    • /
    • pp.369-384
    • /
    • 2015
  • This work presents a free vibration analysis of functionally graded metal-ceramic (FG) beams with considering porosities that may possibly occur inside the functionally graded materials (FGMs) during their fabrication. For this purpose, a simple displacement field based on higher order shear deformation theory is implemented. The proposed theory is based on the assumption that the transverse displacements consist of bending and shear components in which the bending components do not contribute toward shear forces and, likewise, the shear components do not contribute toward bending moments. The most interesting feature of this theory is that it accounts for a quadratic variation of the transverse shear strains across the thickness, and satisfies the zero traction boundary conditions on the top and bottom surfaces of the beam without using shear correction factors. In addition, it has strong similarities with Euler-Bernoulli beam theory in some aspects such as equations of motion, boundary conditions, and stress resultant expressions. The rule of mixture is modified to describe and approximate material properties of the FG beams with porosity phases. By employing the Hamilton's principle, governing equations of motion for coupled axial-shear-flexural response are determined. The validity of the present theory is investigated by comparing some of the present results with those of the first-order and the other higher-order theories reported in the literature. Illustrative examples are given also to show the effects of varying gradients, porosity volume fraction, aspect ratios, and thickness to length ratios on the free vibration of the FG beams.

Fabrication of Ultra-Small Multi-Layer Piezoelectric Vibrational Device Using P(VDF-TrFE-CFE) (P(VDF-TrFE-CFE)를 이용한 초소형 압전 적층형 진동 출력 소자의 제작)

  • Cho, Seongwoo;Glasser, Melodie;Kim, Jaegyu;Ryu, Jeongjae;Kim, Yunjeong;Kim, Hyejin;Park, Kang-Ho;Hong, Seungbum
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.32 no.2
    • /
    • pp.157-160
    • /
    • 2019
  • P(VDF-TrFE-CFE) (Poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)), which exhibits a high electrostriction of about 7%, can transmit tactile output as vibration or displacement. In this study, we investigated the applicability of P(VDF-TrFE-CFE) to wearable piezoelectric actuators. The P(VDF-TrFE-CFE) layers were deposited through spin-coating, and interspaced with patterned Ag electrodes to fabricate a two-layer $3.5mm{\times}3.5mm$ device. This layered structure was designed and fabricated to increase the output and displacement of the actuator at low driving voltages. In addition, a laser vibrometer and piezoelectric force microscope were used to analyze the device's vibration characteristics over the range of ~200~4,200 Hz. The on-off characteristics were confirmed at a frequency of 40 Hz.

Numerical analysis of suction pile behavior with different loading locations and displacement inclinations

  • Kim, Dongwook;Lee, Juhyung;Nsabimana, Ernest;Jung, Young-Hoon
    • Ocean Systems Engineering
    • /
    • v.2 no.3
    • /
    • pp.205-215
    • /
    • 2012
  • Recently, interest of offshore structure construction in South Korea is growing as the land space becomes limited for further development and the renewable energy grows to be more attractive for the replacement of the fossil energy. In order for the optimal construction of optimum offshore floating structures, development of safe and economical offshore foundation technologies is a priority. In this study, the large-deformation behavior of a suction pile, which markets are rapidly growing nowadays, is analyzed for three different loading locations (top, middle, and bottom of the suction pile) with three different displacement inclinations (displacement controlled with displacement inclinations of 0, 10, and 20 degrees from the horizontal). The behavior analysis includes quantifications of maximum resistances, translations, and rotation angles of the suction pile. The suction pile with its diameter of 10 m and height of 25 m is assumed to be embedded in clay, sand, and multi layers of subsea foundation. The soil properties of the clay, sand, and multi layers were determined based on the results of the site investigations performed in the West sea of South Korea. As analyses results, the maximum resistance was observed at the middle of the suction pile with the displacement inclination of 20 degrees, while the translations and rotations resulting from the horizontal and inclined pullouts were not significant until the horizontal components of movements at the loading points reach 1.0 m.

Vibrational Characteristics of High-Speed Motors with Ball Bearings and Gas Foil Bearings Supports (볼 베어링 및 가스 포일 베어링으로 지지되는 소형 고속 전동기의 진동 특성)

  • Seo, Jung Hwa;Kim, Tae Ho
    • Tribology and Lubricants
    • /
    • v.35 no.2
    • /
    • pp.114-122
    • /
    • 2019
  • High-speed rotating machinery requires low cost and reliable bearing elements with low friction, stable rotordynamic characteristics, and a simple design. This study experimentally evaluates the effects of bearing-support elements on the vibrational characteristics of a small-sized, high-speed permanent magnetic motor. A series of coast down tests from 100 krpm characterize the vibrational behaviors, rotor displacement, and housing acceleration of motors supported by ball bearings, ball bearings with a metal mesh damper, and gas foil bearings, respectively. Two eddy-current sensors installed in the horizontal and vertical directions measure the displacement of the rotor at its front nut, and a 3-axis accelerometer attached to the motor housing measures the housing acceleration. The test results reveal that synchronous (1X) vibration components most significantly affect the rotor displacement and housing acceleration, independent of the bearing-support elements. The motor supported by the deep-groove ball bearings results in the largest rotor vibrations increasing with speed; this is due to the absence of a damping mechanism. Additionally, the metal mesh damper effectively reduces the rotor displacement, housing acceleration, and sound-pressure level in the high-speed region (i.e., above 40 krpm), thus implying its substantial damping performance when installed on the outer race of the ball bearing. Lastly, the gas foil bearing supported motor yields the smallest rotor displacement, housing acceleration, and lowest sound-pressure level because of its hydrodynamic airborne operation, which does not require rolling elements that may cause mechanical friction and vibrations.

Experimental Assessment of Numerical Models for Reinforced Concrete Shear Walls with Deficient Details (결함 상세를 포함하는 철근콘크리트 전단벽의 수치 모델에 관한 실험적 평가)

  • Jeon, Seong-Ha;Park, Ji-Hun
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.20 no.4
    • /
    • pp.211-222
    • /
    • 2016
  • Reinforced concrete shear walls with deficient reinforcement details are tested under cyclic loading. The deficiency of reinforcement details includes insufficient splice length in U-stirrups at the ends of horizontal reinforcement and boundary column dowel bars found in existing low- to mid-rise Korean buildings designed non-seismically. Three test specimens have rectangular, babel and flanged sections, respectively. Flexure- and shear-controlled models for reinforced concrete shear walls specified in ASCE/SEI 41-13 are compared with the flexural and shear components of force-displacement relation extracted separately from the top displacement of the specimen based on the displacement data measured at diverse locations. Modification of the shear wall models in ASCE/SEI 41-13 is proposed in order to account for the effect of bar slip, cracking loads in flexure and shear. The proposed modification shows better approximation of the test results compared to the original models.

Geometrically non-linear transient C° finite element analysis of composite and sandwich plates with a refined theory

  • Kommineni, J.R.;Kant, T.
    • Structural Engineering and Mechanics
    • /
    • v.1 no.1
    • /
    • pp.87-102
    • /
    • 1993
  • A $C^{\circ}$ continuous finite element formulation of a higher order displacement theory is presented for predicting linear and geometrically non-linear in the sense of von Karman transient responses of composite and sandwich plates. The displacement model accounts for non-linear cubic variation of tangential displacement components through the thickness of the laminate and the theory requires no shear correction coefficients. In the time domain, the explicit central difference integrator is used in conjunction with the special mass matrix diagonalization scheme which conserves the total mass of the element and included effects due to rotary inertia terms. The parametric effects of the time step, finite element mesh, lamination scheme and orthotropy on the linear and geometrically non-linear responses are investigated. Numerical results for central transverse deflection, stresses and stress resultants are presented for square/rectangular composite and sandwich plates under various boundary conditions and loadings and these are compared with the results from other sources. Some new results are also tabulated for future reference.