共查询到18条相似文献,搜索用时 129 毫秒
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对在热环境中功能梯度材料(FGM)输流管道流固耦合热横向振动问题,基于哈密顿原理和Euler-Bernoulli梁理论,建立了端部不可移简支FGM输流管道的力学模型和运动微分方程。引入量纲为一的量,把运动微分方程离散为以量纲归一化广义坐标表达的常微分方程组。应用哈密顿对偶体系理论,得到了哈密顿正则方程,通过分离变量法得到了哈密顿体系下系统的热本征值和本征解的表达式。算例表明,端部不可移简支FGM输流管道的量纲为一的复频率虚部随着梯度指标的增大而增大,随着量纲为一的温度轴力的增大而减小。 相似文献
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利用粘弹性微分型本构关系和薄板理论,对线性变厚度粘弹性矩形薄板建立了在切向均布随从力作用下的运动微分方程,采用微分求积法研究了在随从力作用下线性变厚度粘弹性矩形薄板的稳定性问题,具体对对边简支对边固支和三边简支一边固支条件下体变为弹性、畸变服从Kelvin-Voigt模型的变厚度粘弹性矩形板在随从力下的广义特征值问题进行了求解,分析了薄板的长宽比、厚度比及材料的无量纲延滞时间的变化对随从力作用下矩形薄板的失稳形式及相应的临界荷载的影响. 相似文献
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研究在外激励力与磁场作用下轴向运动铁磁梁的磁弹性非线性主共振问题.基于弹性理论和电磁理论,给出梁的动能和弹性势能表达式,根据哈密顿原理,推导出磁场中轴向运动铁磁梁的磁弹性双向耦合非线性振动方程.通过伽辽金积分法进行离散,得出两端简支边界条件下铁磁梁磁弹性非线性强迫振动方程.应用多尺度法对方程进行求解,得出幅频响应方程.最后通过算例,给出铁磁梁的幅频特性曲线、振幅-磁感应强度和振幅-外激励力曲线并进行分析.结果显示,在幅频响应曲线中铁磁梁的轴向运动速度、外激励力、轴向拉力越大,共振振幅越大;而磁感应强度越大,振幅越小. 相似文献
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基于直法线假设,采用可伸长梁的几何非线性理论,建立了功能梯度材料弹性组合曲梁受切线均布随从力作用下的静态大变形数学模型。该模型不仅计及了轴线伸长,同时也精确地考虑了梁的初始曲率对变形的影响以及轴向变形与弯曲变形之间的耦合效应。用打靶法数值求解了由金属和陶瓷两相材料所构成的一种FGM组合曲梁在沿轴线均布切向随动载荷作用下的非线性平面弯曲问题,给出了不同梯度指标下FGM弹性曲梁随载荷参数大范围变化的平衡路径,并与金属和陶瓷两种单相材料曲梁的相应特性进行了比较。 相似文献
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《应用力学学报》2019,(5)
研究了均布横向载荷作用下轴向运动SMA(形状记忆合金)层合梁的横向非线性振动。考虑轴向运动效应、轴力等因素的综合影响,利用力平衡条件、变形协调方程及SMA多项式函数的本构关系,建立了SMA层合梁在均布横向载荷作用下的动力学方程。针对两端简支边界条件,通过伽辽金积分得到了轴向运动SMA层合梁横向振动微分方程。应用平均法得到了横向载荷作用下系统主共振幅频响应方程,对理论结果进行了数值验证;分析了轴向运动速度、温度、激励参数对系统稳态响应的影响。结果表明:轴向速度、轴向载荷的变化只对系统共振频率产生影响;在外激励幅值较大时,温度增加和SMA层增厚对系统产生了相同的减振效果。 相似文献
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揭敏 《应用数学和力学(英文版)》1997,18(4):399-405
I.Introduction'Whenadeformableobjectmovinginamedium,thedirectionsofinteractiveforcessuchasfrictionalforceshouldvarywiththedeformationoftheobject.Thisisakindofnonconservativeforces.Forexample,thedirectionofgasfrictionalforceactingontherocketsandthefossiles… 相似文献
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B.S. Shvartsman 《International Journal of Non》2009,44(2):249-34
The static analysis of the flexible non-uniform cantilever beams under a tip-concentrated and intermediate follower forces is considered. The angles of inclination of the concentrated forces with respect to the deformed axis of the beam remain unchanged during deformation. The governing non-linear boundary-value problem is reduced to an initial-value problem by change of variables. The resulting problem can be solved without iterations. It is shown that there are no critical loads in the Euler sense (divergence) for any flexural-stiffness distribution and angles of inclination of the follower forces. In particular, if the follower forces are tangential, the rectilinear shape of the non-uniform cantilever beam is the only possible equilibrium configuration. In this paper some equilibrium configurations of the uniform cantilever under normal or tangential follower forces are presented using direct method. 相似文献
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Based on geometrically non-linear theory for extensible elastic beams, governing equations of statically post-buckling of a beam with one end hinged and the other fixed, subjected to a uniformly distributed, tangentially compressing follower forces are established. They consist of a boundary-value problem of ordinary differential equations with a strong non-linearity, in which seven unknown functions are contained and the arc length of the deformed axis is considered as one of the basic unknown functions. By using shooting method and in conjunction with analytical continuation, the non-linear governing equations are solved numerically and the equilibrium paths as well as the post-buckled configurations of the deformed beam are presented. A comparison between the results of conservative system and that of the non-conservative systems are given. The results show that the features of the equilibrium paths of the beams under follower loads are evidently different from that under conservative ones. 相似文献
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FLUTTER INSTABILITY OF SUPPORTED PIPES CONVEYING FLUID SUBJECTED TO DISTRIBUTED FOLLOWER FORCES 总被引:1,自引:0,他引:1
Lin Wang 《Acta Mechanica Solida Sinica》2012,25(1):46-52
In the past decades,it has been reported that divergence is the expected form of instability for fluid-conveying pipes with both ends supported.In this paper,the form of instability of supported pipes ... 相似文献
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《International Journal of Solids and Structures》2002,39(9):2387-2399
The non-conservative stability of non-uniform columns under the combined action of concentrated and variably distributed forces is solved analytically. Two types of follower force system are considered: (i) concentrated follower forces and variably distributed follower forces, (ii) concentrated follower forces and variably distributed conservative forces. The exact solutions for stability of four kinds of one-step non-uniform columns subjected to the two types of follower force system are derived for the first time. Then a new exact approach, which combines the exact solutions of one-step columns and the transfer matrix method, is presented for the non-conservative stability analysis of multi-step non-uniform columns. The advantage of the proposed method is that the resulting eigenvalue equation for a multi-step non-uniform column with any kinds of two end support configurations, an arbitrary number of spring supports and concentrated masses can be conveniently determined from a second order determinant. The decrease in the determinant order, as compared with previously developed procedures, leads to significant savings in the computational effort. A numerical example shows that the results obtained from the proposed method are in good agreement with those determined from the finite element method (FEM), but the proposed method takes less computational time than FEM. 相似文献
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Summary This paper treats the solution of separable non-selfadjoint initial-boundary-value problems using Green's function approach. Specifically, the dynamic response of an isotropic, homogeneous and linearly elastic clamped-free rod when perturbed by a time varying driving force and under constant uniformly distributed tangential follower forces is determined.
To the best knowledge of the first author this paper represents the last of numerous scientific contributions made by Professor Leipholz prior to his unexpected death on March 22, 1988 相似文献
Das dynamische Verhalten eines elastischen Stabes unter gleichmäßig verteilten, tangential mitgehenden Kräften
Übersicht In dieser Arbeit wird die separable Lösung nicht-selbstadjungierter Anfangs-Randwertprobleme mittels Anwendung der Greenschen Funktion behandelt. Insbesondere wird das dynamische Verhalten eines isotropen, homogenen und linear elastischen Stabes betrachtet, der unten eingespannt, oben frei ist und der einer zeitlich veränderlichen Erregerkraft sowie konstanten, tangential mitgehenden Kräften unterworfen worden ist.
To the best knowledge of the first author this paper represents the last of numerous scientific contributions made by Professor Leipholz prior to his unexpected death on March 22, 1988 相似文献
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Nguyen Van Khang Nguyen Phong Dien Nguyen Thi Van Huong 《Archive of Applied Mechanics (Ingenieur Archiv)》2009,79(10):939-953
The main objective of the paper is to investigate the dynamic response of the prestressed beams on rigid supports to moving
concentrated loads. The governing equation of the transverse vibration of a prestressed continuous beam under the ununiformly
distributed load is analytically formulated, taking into account the effect of the prestressing. The forced transverse vibration
of the beam under the action of a large number of moving bodies has been investigated by using the method of substructures.
In addition, the reaction forces at every rigid supports can be determined from the obtained differential equations. A comparison
between the numerical results for the prestressed and the non-prestressed beam is presented to show the influence of the prestressing
and the moving velocity of the bodies on the dynamic response of the beam. The calculating results are also examined and validated
by experimental measurements at a large ferroconcrete bridge in Vietnam. 相似文献