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51.
V. N. Paimushin V. A. Ivanov S. A. Lukankin A. A. Bushkov A. E. Vyalkov 《Mechanics of Composite Materials》2005,41(1):23-32
Equations are set up for describing, in a correct statement and with an accuracy sufficient in actual practice, the shear buckling modes (BMs) of cylindrical sandwich shells with a transversely soft core of arbitrary thickness. Based on them, solutions are obtained to a number of problems on the buckling instability according to shear modes under some force and thermal loadings. It is found that the BMs occur in the shell along the circumferential and axial directions if, in the precritical state, a normal compressive stress arises in the transverse direction. It is shown that this condition is fulfilled in the following cases: in axial tension of the shell with unequal forces applied to the end faces of bearing layers (the parameter of critical load is maximum if the tensile forces are equal); under external (internal) pressure; on cooling the outer and heating the inner layers. The results obtained are presented in the form of simple analytical formulas for determining the corresponding critical parameters of the force and thermal actions.Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 1, pp. 37–48, January–February, 2005. 相似文献
52.
This paper is concerned with the limit relations from the Euler equations of one‐dimensional compressible fluid flow and the magnetohydrodynamics equations to the simplified transport equations, where the δ‐shock waves occur in their Riemann solutions of the latter two equations. The objective is to prove that the Riemann solutions of the perturbed equations coming from the one‐dimensional simplified Euler equations and the magnetohydrodynamics equations converge to the corresponding Riemann solutions of the simplified transport equations as the perturbation parameterx ε tends to zero. Furthermore, the result can also be generalized to more general situations. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
53.
In this paper,we study two-dimensional Riemann boundary value problems of Euler system for the isentropic and irrotational Chaplygin gas with initial data being two constant states given in two sectors respectively,where one sector is a quadrant and the other one has an acute vertex angle.We prove that the Riemann boundary value problem admits a global self-similar solution,if either the initial states are close,or the smaller sector is also near a quadrant.Our result can be applied to solving the problem of shock reflection by a ramp. 相似文献
54.
为减小油气输送难度和避免原油固化,石油、天然气通常在高温高压下输送.输送过程中的高温和高压导致海底管线中产生较大的附加应力,附加应力的不断累积造成管线发生整体屈曲.对于埋地的海底管线通常会产生竖向屈曲大变形而影响使用甚至破坏.因此,需对有可能产生整体屈曲的管线采取工程防护措施.结合我国海洋工程中管线常用的铺设及保护措施,对处于保护状态下管线由温度应力引起的整体屈曲特性进行理论分析和数值推导,对沟槽保护、沟槽掩埋保护以及压块保护措施的有效性进行了系统分析和对比. 相似文献
55.
In this paper, we consider the Cauchy problems for compressible Euler equations with damping. In terms of the Littlewood–Paley decomposition and Bony's para‐product formula, we prove the global existence, uniqueness and asymptotic behavior of the solution in the critical Besov space comparing with previous results. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
56.
F. Elias I. Drikis A. Cebers C. Flament J.-C. Bacri 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,3(2):203-209
Two-dimensional magnetic fluid foams are cellular structures whose framework is made of magnetic fluid. The features of these
equilibrated patterns are driven by a control parameter: the amplitude of the applied magnetic field. When the latter is rapidly
increased, an instability occurs: the walls between cells undulate. Such an instability has also been observed in other 2D
cellular structures, which exist for instance in Langmuir monolayers or in magnetic garnets thin films. In this paper we give
a theoretical analysis of this instability, the issues of which are shown to be well confirmed by experiments and numerical
simulations.
Received: 13 October 1997 / Received in final form: 28 January 1998 / Accepted: 9 March 1998 相似文献
57.
关于完全气体无粘可压流动的解析解 总被引:3,自引:1,他引:3
本文导出了一套不定常二、三维完全气体无粘可压流动的代数显式解析解,这些解除在理论上有重要意义外,还可以用来作为检验与发展各种数值解法的标准解.另外,文中还将提出和讨论二维可压等熵流的一个很有意思的疑难. 相似文献
58.
Ram Manohar & Rajen Kumar Sinha 《计算数学(英文版)》2022,40(2):147-176
This article studies a posteriori error analysis of fully discrete finite element approximations for semilinear parabolic optimal control problems. Based on elliptic reconstruction approach introduced earlier by Makridakis and Nochetto [25], a residual based a posteriori error estimators for the state, co-state and control variables are derived. The space discretization of the state and co-state variables is done by using the piecewise linear and continuous finite elements, whereas the piecewise constant functions are employed for the control variable. The temporal discretization is based on the backward Euler method. We derive a posteriori error estimates for the state, co-state and control variables in the $L^\infty(0,T;L^2(\Omega))$-norm. Finally, a numerical experiment is performed to illustrate the performance of the derived estimators. 相似文献
59.
Thermal Buckling Analysis of FGM Sandwich Circular Plates Under Transverse Nonuniform Temperature Field Actions北大核心CSCD 下载免费PDF全文
Based on the von Kármán geometric nonlinear plate theory, the displacement⁃type geometric nonlinear governing equations for FGM sandwich circular plates under transverse nonlinear temperature field actions were derived. With the immovable clamped boundary condition, the analytical formula for dimensional critical buckling temperature differences of the system was obtained from the solution of the linear eigenvalue problem. Moreover, the 2⁃point boundary value problem of ordinary differential equations was solved with the shooting method. The effects of geometric parameters, constituent material properties, gradient indexes, temperature field parameters and layer⁃thickness ratios on the critical buckling temperature differences, the thermal postbuckling equilibrium paths, and the buckling equilibrium configurations of FGM sandwich circular plates, were investigated. The results show that, with the increases of the thickness⁃radius ratio, the relative thickness of the FGM layer and the gradient index, the FGM sandwich circular plate's critical buckling temperature difference will increase monotonically. Given a fixed radius and a fixed total thickness, the postbuckling deformation of the FGM sandwich circular plate will decrease significantly with the relative thickness of the FGM layer. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved. 相似文献
60.
《Journal of Nonlinear Mathematical Physics》2013,20(3):299-309
The conserved quantities for the heated radial liquid jet and the heated radial free jet are established by using conservation laws. The flow in a heated radial jet is described by Prandtl's momentum boundary layer equation, the continuity equation and the energy equation. Viscous dissipation is neglected. The multiplier approach is used to derive the conservation laws for the system of three equations for the velocity components and the temperature and three conserved vectors are obtained. The conservation laws for the system of two partial differential equations for the stream function formulation are also computed by the multiplier approach and three conserved vectors are obtained. One of these is a non-local conserved vector for the system. The conserved quantities for the heated radial liquid jet and the heated radial free jet, emitted into a stationary fluid of uniform temperature θ∞, are derived by integrating the conservation laws across the jet. 相似文献