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为探究着角和攻角对薄芳纶层合板抗平头弹侵彻性能的影响,建立了三维有限元仿真模型,对4 mm厚芳纶层合板在着角单独作用下以及着/攻角联合作用下的弹道行为进行了计算.通过弹丸的剩余速度、靶板的极限弹道速度及穿孔能量阈值反映了芳纶层合板的抗侵彻性能,分析了其在不同工况下的变形与破坏机理.结果表明:薄芳纶层合板的弹道极限速度随初始着角的增加先减小后增大;随着入射速度的增大和初始着角的减小,着角改变量和攻角改变量均有减小的趋势;对于固定的着角,负攻角不利于子弹侵彻,正攻角有利于侵彻. 相似文献
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弹性厚矩形板受迫振动的功的互等定理法 总被引:1,自引:0,他引:1
本文将功的互等定理法(RTM)推广应用于求解基于Reissner理论的厚矩形板受迫振动问题·本文导出了厚矩形板动力基本解;给出了三边固定一边自由厚矩形板在均布简谐干挠力作用下稳态响应的精确解析解·这是计算厚矩形板受振动稳态响应的一个简便通用的方法· 相似文献
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求解厚矩形板弯曲问题的功的互等定理法 总被引:22,自引:0,他引:22
在本文中,功的互等定理法(RTM)被推广于求解基于Reissner理论的厚矩形板弯曲问题。首先,本文绘出了厚矩形板弯曲的基本解;其次,给出了三边固定一边自由在均布载荷作用下厚矩形板弯曲的精确解析解;最后,我们分析了本文解的数值结果。 相似文献
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本文以中心挠度为摄动参数,将矩形板大挠度问题的非线性偏微分方程缉转化为几个线性的偏微分方程组,然后分别用样条有限点法和样条有限元法求解,得到了在多种边界条件下具有任意长宽比的,受均布荷载的矩形板的解答,给出了板中面的位移、挠度的解析表达式;并编制了相关的计算机程序.计算的结果与现有的其他理论的结果作了比较,表明本文的结果是良好的. 相似文献
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本文提出一种一般解析方法——空间变量变换法,用以求解任意边界条件下圆柱厚壳自由振动问题.运用本文方法对悬臂圆柱厚壳的自振特性作了计算,计算结果与薄壳理论相应结果及试验值作了比较.理论分析和计算结果表明,本文方法具有很好的收敛性和精确性,可以推广用于分析梁、板、壳的自由振动. 相似文献
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Elasticity Solutions for Cylindrical Bending of Functionally Graded Piezoelectric Material Plates北大核心CSCD 下载免费PDF全文
功能梯度压电材料(FGPM)同时兼具功能梯度材料和压电材料特性,可为多功能或智能化轻质结构设计提供支撑,在诸多领域有着广泛的应用前景.将Mian和Spencer功能梯度板理论由功能梯度弹性材料推广到功能梯度压电材料,解析研究了FGPM板的柱面弯曲问题,其中,材料弹性常数、压电和介电参数沿板厚方向可以任意连续变化.最终,给出了FGPM板受横向均布荷载作用下柱面弯曲问题的弹性力学解.通过算例分析,重点讨论了压电效应对FGPM板静力响应的影响. 相似文献
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在裂纹尖端的应力分量都只是θ的函数的条件下,利用平衡方程和静水应力相关屈服条件,本文导出了静止平面应力裂纹尖端的静水应力相关理想塑性应力场的一般解析表达式.将这些一般解析表达式用于具体裂纹,我们就得到Ⅰ型和Ⅱ型裂纹尖端的静水应力相关理想塑性应力场的解析表达式. 相似文献
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M. A. Elganainy 《Applied Mathematical Modelling》1986,10(6):394-400
This paper presents a solution, using a conformal mapping technique, for the problem of seepage beneath two structures with intermediate filter built on two pervious strata. The lower stratum has a higher permeability than the upper one. Formulae are derived for calculating the dimensionless heads acting on both the upstream and downstream structures. Also, equations are derived for determining the values of the exit gradients along both the intermediate filter and the downstream bed, and the seepage discharges. For given boundary conditions, the seepage characteristics are calculated using the derived formulae; a sample from the results of such calculations is presented. 相似文献
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V.G. Yakhno H. Çerdik Yaslan 《Journal of Computational and Applied Mathematics》2011,235(16):4802-4815
The dynamic system of anisotropic elasticity from three second order partial differential equations is written in the form of the time-dependent first order symmetric hyperbolic system with respect to displacement velocity and stress components. A new method of deriving the time-dependent fundamental solution of the obtained system is suggested in this paper. This method consists of the following. The Fourier transform image of the fundamental solution with respect to a space variable is presented as a power series expansion relative to the Fourier parameters. Then explicit formulae for the coefficients of these power series are derived successively. Using these formulae the computer calculation of fundamental solution components (displacement velocity and stress components arising from pulse point forces) has been made for general anisotropic media (orthorhombic and monoclinic) and the simulation of elastic waves has been obtained. These computational examples confirm the robustness of the suggested method. 相似文献
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楔型向错偶极子和裂纹的干涉效应 总被引:2,自引:0,他引:2
研究了晶体材料中一个楔型向错偶极子与裂纹的弹性干涉效应.运用复变函数方法获得了复势函数和应力场的封闭形式解答,导出了裂纹尖端应力强度因子和作用在向错偶极子中心点像力的解析表达式.获得了向错偶极子的位置、方向和偶臂长度对裂纹尖端应力强度因子的影响规律,并讨论了裂纹附近向错偶极子的平衡位置.结果表明向错偶极子靠近裂纹尖端时,对应力强度因子有明显的屏蔽或反屏蔽作用. 相似文献
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A dynamic contact problem which reduces to a singular integral equation with two fixed singularities
V.G. Popov 《Journal of Applied Mathematics and Mechanics》2012,76(3):348-357
The problem of the harmonic sheat oscillations of an elastic strip, coupled to an elastic half-space is considered. Using the method of integral transformations, the problem is reduced to a singular integral equation in the contact stresses in the region where the strip and the half-space are coupled when there are two fixed singularities at points bounding the integration intervals. One of the main results of this paper is the method of solving this equation numerically, taking into account the true singularity of the solution and based on the use of special quadrature formulae for singular integrals. The approximate solution obtained provides the possibility of numerically investigating the effect of the oscillation frequency and the ratio of the elastic constants of the strip and the half-space on the stress distribution in the contact area. 相似文献
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《Journal of Applied Mathematics and Mechanics》2002,66(4):637-643
The problem of the unilateral contact without friction for a punch, the face of which is characterized by a rapid change in the neighbourhood of the a priori unknown boundary of the contact area, is investigated. Asymptotic formulae are obtained for the function which describes the variation of the contact area and the contact-pressure density in the boundary-layer region. The problem of the behaviour of the contact pressures in the neighbourhood of a smoothed stress concentrator is considered. 相似文献
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N.S. Khabeyev V.Sh. ShagapovYu.A. Yumagulova 《Journal of Applied Mathematics and Mechanics》2013,77(1):33-38
The reduction in the vapour pressure in a closed volume as a consequence of condensation at the interface with a cold liquid is investigation. Approximate formulae are obtained that describe the pressure drop when a vapour is in contact with cold water in the form of a liquid layer on a horizontal surface and also in the form of drops. 相似文献
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The axisymmetric torsional fretting contact between a rigid conducting spherical punch and a functionally graded piezoelectric material (FGPM) coating is studied in this paper. The exponential model is used to simulate the inhomogeneous electro-mechanical properties of the FGPMs coating. The conducting spherical punch with a constant surface electric potential is considered in the contact. A normal force and a cyclic torque are applied to the two contact bodies. The applied torque produces an outer annular slip area and an inner stick area. The torsion angle is produced within the inner stick area as a rigid body. With the aid of the Hankel integral transform technique, we can reduce the contact problem to the singular integral equations of the Cauchy type. Then the unknown electro-mechanical fields and stick/slip area can be obtained numerically. The effect of the gradient index on the surface electro-mechanical fields is discussed at loading and unloading phases. The Mises stress and principal stress at the contact surface are also discussed to predict the possible location of fretting damage and failure. 相似文献
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Analytical methods for solving problems of the interaction of punches with two-layer bases are described using in the example of the axisymmetric contact problem of the theory of elasticity of the interaction of an absolutely rigid sphere (a punch) with the inner surface of a two-layer spherical base. It is assumed that the outer surface of the spherical base is fixed, that the layers have different elastic constants and are rigidly joined to one anther, and that there are no friction forces in the contact area. Several properties of the integral equation of this problem are investigated, and schemes for solving them using the asymptotic method and the direct collocation method are devised. The asymptotic method can be used to investigate the problem for relatively small layer thicknesses, and the proposed algorithm for solving the problem by the collocation method is applicable for practically any values of the initial parameters. A calculation of the contact stress distribution, the parameters of the contact area, and the relation between the displacement of the punch and the force acting on it is given. The results obtained by these methods are compared, and a comparison with results obtained using Hertz, method is made for the case in which the relative thickness of the layers is large. 相似文献
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Yue-Ting Zhou Kang Yong Lee Yong Hoon Jang 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2013,64(3):831-861
The frictional contact problem of anisotropic materials under a moving rigid stamp is solved exactly. Inside the contact region, the Coulomb friction law is applied. Both Galilean transformation and Fourier transform are employed to get the appropriate fundamental solutions, which can lead to real solutions of physical quantities no matter whether the eigenvalues are real or complex. The complicated mixed boundary value problem is converted to singular integral equations of the second kind, which are solved analytically in terms of elementary functions for either a triangular or a parabolic stamp. Explicit formulae of surface stresses are obtained. Numerical analyses are performed in detail to reveal the surface damage mechanism. It is also found that in the frictionally moving contact problem, the friction coefficient has a more important role than the moving velocity. 相似文献