• 제목/요약/키워드: force integration

검색결과 355건 처리시간 0.032초

Supersonic Axisymmetric Minimum Length Nozzle Conception at High Temperature with Application for Air

  • Zebbiche, Toufik
    • International Journal of Aeronautical and Space Sciences
    • /
    • 제9권1호
    • /
    • pp.1-30
    • /
    • 2008
  • When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

Perturbation method for the dynamic analysis of a bistable oscillator under slow harmonic excitation

  • Luongo, Angelo;Casciati, Sara;Zulli, Daniele
    • Smart Structures and Systems
    • /
    • 제18권1호
    • /
    • pp.183-196
    • /
    • 2016
  • In this paper a nonlinear, bistable, single degree of freedom system is considered. It consists of a Duffing oscillator externally excited by a non-resonant, harmonic force. A customized perturbation scheme is proposed to achieve an approximate expression for periodic solutions. It is based on the evaluation of the quasi-steady (slow) solution, and then on a variable change followed by two perturbation steps which aim to capture the fast, decaying contribution of the response. The reconstructed solution, given by the sum of the slow and fast contributions, is in a good agreement with the one obtained by numerical integration.

Crack-contact problem for an elastic layer with rigid stamps

  • Birinci, Ahmet
    • Structural Engineering and Mechanics
    • /
    • 제37권3호
    • /
    • pp.285-296
    • /
    • 2011
  • The plane crack-contact problem for an infinite elastic layer with two symmetric rectangular rigid stamps on its upper and lower surfaces is considered. The elastic layer having an internal crack parallel to its surfaces is subjected to two concentrated loads p on its upper and lower surfaces trough the rigid rectangular stamps and a pair of uniform compressive stress $p_0$ along the crack surface. It is assumed that the contact between the elastic layer and the rigid stamps is frictionless and the effect of the gravity force is neglected. The problem is reduced to a system of singular integral equations in which the derivative of the crack surface displacement and the contact pressures are unknown functions. The system of singular integral equations is solved numerically by making use of an appropriate Gauss-Chebyshev integration formula. Numerical results for stress-intensity factor, critical load factor, $\mathcal{Q}_c$, causing initial closure of the crack tip, the crack surface displacements and the contact stress distribution are presented and shown graphically for various dimensionless quantities.

Comparison of fully coupled hydroelastic computation and segmented model test results for slamming and whipping loads

  • Kim, Jung-Hyun;Kim, Yonghwan;Korobkin, Alexander
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • 제6권4호
    • /
    • pp.1064-1081
    • /
    • 2014
  • This paper presents a numerical analysis of slamming and whipping using a fully coupled hydroelastic model. The coupled model uses a 3-D Rankine panel method, a 1-D or 3-D finite element method, and a 2-D Generalized Wagner Model (GWM), which are strongly coupled in time domain. First, the GWM is validated against results of a free drop test of wedges. Second, the fully coupled method is validated against model test results for a 10,000 twenty-foot equivalent unit (TEU) containership. Slamming pressures and whipping responses to regular waves are compared. A spatial distribution of local slamming forces is measured using 14 force sensors in the model test, and it is compared with the integration of the pressure distribution by the computation. Furthermore, the pressure is decomposed into the added mass, impact, and hydrostatic components, in the computational results. The validity and characteristics of the numerical model are discussed.

완충 포장한 모니터의 자유낙하시험을 위한 유한요소모델 (A Finite Element Model for the Free Drop Test of the Monitor Packed by Cushioning Materials)

  • 황용익;윤성호
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 2002년도 가을 학술발표회 논문집
    • /
    • pp.78-85
    • /
    • 2002
  • This paper deals with the finite element model of the monitor for the simulation of directional free drop tests such as backward, sideward, edge and vertex drop. The model was made for an unconditional stable solution for the explicit integration algorithm. The general behaviors at the time of impact were found to well correlate with the actual situation in terms of acceleration, displacement, contact force and stress of monitor components even though the experiment of the associated drop is performed for the validity of the model.

  • PDF

판재성형 정적해석에서 유한요소의 영향에 대한 비교연구 (A Comparative Study on Effect of Finite Element in Static Analysis of Sheet Metal Forming)

  • 윤용석;박종진
    • 소성∙가공
    • /
    • 제9권1호
    • /
    • pp.17-26
    • /
    • 2000
  • A series of parametric study was performed for the investigation on the influence of analysis parameters to the solution behavior in the elastic-plastic-static analysis of several sheet metal forming processes, such as deflection by a point force under plane strain and axisymmetric conditions, plane strain bending by a punch, axisymmetric stretching by a punch, axisymmetric bulging by hydraulic pressure, and axisymmetric deep drawing by a punch. The parameters considered are kind of element, number of elements, integration scheme for elemental equation and friction coefficient. Results obtained for different selections of those parameters were compared with each other, experimental measurements and analytical solution.

  • PDF

조화집중하중을 받는 무한보에서의 음향방사 (Sound Radiation From Infinite Beams Under the Action of Harmonic Point Forces)

  • 김병삼;홍동표
    • 소음진동
    • /
    • 제2권1호
    • /
    • pp.33-39
    • /
    • 1992
  • The problem of sound radiation from infinite elastic beams under the action of harmonic point forces is studied. The reaction due to fluid loading on the vibratory response of the beam is taken into account. The beam is assumed to occupy the plane z = 0 and to be axially infinite. The beam material and the elastic foundation re assumed to be lossless and Bernoulli-Euler beam theory including a tension force (T), damping coefficient (C) and stiffness of foundation $(\kappa_s)$ will be employed. The non-dimensional sound power is derived through integration of the surface intensity distribution over the entire beam. The expression for sound power is integrated numerically and the results are examined as a function of wavenumber ratio$(\gamma)$ and stiffness factor$(\Psi)$. Here, our purpose is to explain the response of sound power over a number of non-dimensional parameters describing tension, stiffness, damping and foundation stiffness.

  • PDF

조화분포이동하중을 받는 무한보에서의 음향방사 (Sound Radiation From Infinite Beams Under the Action of Harmonic Moving Line Forces)

  • 김병삼;이태근;홍동표
    • 소음진동
    • /
    • 제3권3호
    • /
    • pp.245-251
    • /
    • 1993
  • The problem of sound radiation from infinite elastic beams under the action on harmonic moving line forces is studies. The reaction due to fluid loading on the vibratory response of the beam is taken into account. The beam is assumed to occupy the plane z=0 and to be axially infinite. The beam material and elastic foundation are assumed to be lossless and Bernoulli-Euler beam theory including a tension force (T), damping coefficient (C) and stiffness of foundation $(\kappa_s)$ will be employed. The non-dimensional sound power is derived through integration of the surface intensity distribution over the entire beam. The expression for sound power is integrated numerically and the results examined as a function of Mach number (M), wavenumber ratio$(\gamma{)}$ and stiffness factor $(\Psi{)}$. Here, our purpose is to explain the response of sound power over a number of non-dimensional parameters describing tension, stiffness, damping and foundation stiffness.

  • PDF

New Inductance Simulator Topologies Realized with DO-OTAs

  • Kuntman, Hakan;Menekay, Serdar;Cicekoglu, Oguzhan;Kuntman, Ayten
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2000년도 ITC-CSCC -1
    • /
    • pp.391-394
    • /
    • 2000
  • In this paper four lossy and one lossless inductance simulator topologies employing a single DO-OTA are presented. For the topologies proposed the inductance $L_{eq}$ and the series resistance $R_{eq}$ are independently adjustable. The topologies employ a single capacitor and are canonic in the number of capacitors. The resistors in the topologies can easily be implemented also with DO-OTAs. In this case the topologies proposed change to DO-OTA-C inductor simulators which is important from the integration point of view. Simulation results are included to verify theory.

  • PDF

복합시스템 환경에서의 능력진화프로세스 적용 (Applications of Capability Evolution Process in the SoS Environment)

  • 송상기;권용수
    • 한국군사과학기술학회지
    • /
    • 제13권1호
    • /
    • pp.57-66
    • /
    • 2010
  • This work describes an applications of CEP(Capability Evolution Process) in the SoS(Systems of Systems) environment. SoS is a set of systems that results when independent systems are integrated into a larger systems that delivers unique capability. CEP is focused on system performance and integration, interoperability requirement between systems within a force package. This work analyzes CEP and applies to OO joint marinetime operation. From these results, the possiblity of the CEP application in the SoS environment is presented.