首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 68 毫秒
1.
本文采用弹性圆锥扁壳中心无量纲振幅和壳体母线的倾角为参数,将挠度、应力函数的导数以及自由振动频率展开为双参量的幂级数形式,用直接摄动法获得各级递推线性偏微分方程,应用变分法求得各级递推方程的近似解答,从而给出弹性圆锥扁壳非线性自由振动频率的基本公式。  相似文献   

2.
本文采用弹性圆锥扁壳中心无量纲振幅和壳体母线的倾角为参数,将挠度、应力函数的导数以及自由振动频率展开为双参量的幂级数形式.用直接摄动法获得各级递推线性偏微分方程.应用变分法求得各级递推方程的近似解答.从而给出弹性圆锥扁壳非线性自由振动频率的基本公式。  相似文献   

3.
基于各向同性及各向异性圆板的大挠度理论,研究了具有光滑中心的波纹圆板的非线性自由振动。以波纹板的中心最大振幅为摄动参数,采用摄动变分法,得出了波纹板的二次近似非线性固有频率。  相似文献   

4.
两类弱非线性振动微分方程的插值摄动解法   总被引:3,自引:0,他引:3  
本文分别用插值摄动法的两种不同方法(第一,第二解法)求解了两类弱非线性振动问题,用第二解法得到的Duffing方程的解,精度很高,当小参数不是很小时,甚至比L-P法的结构更加精确,用第一解法求解有阻尼的自由振动问题时,由于可以公式化,故求解过程十分简便,本文选取的初始零级近似解,具有新的特色。  相似文献   

5.
用插值摄动法求得了一类保守系统奇次弱非线性振动问题的一级近似解,精度好,甚至比多尺度法还更好,计算过程简单。  相似文献   

6.
波纹壳是传感器弹性元件的一类重要形式,也是精密仪器仪表弹性元件中的一类重要形式.由于波纹壳形状复杂、参数众多、厚度薄,对其进行非线性分析非常重要同时也是十分困难的.本文考虑一种在传感器弹性元件中有重要应用价值的正弦波纹浅球壳体,将这种壳体视为结构上的圆柱正交异性扁球壳,根据Andryewa的思想,分别得到了正弦波纹壳径向、环向在拉伸、弯曲下的等价的四个各向异性参数;建立了正弦波纹扁球壳的非线性强迫振动微分方程;得到了正弦波纹扁球壳非线性强迫振动的共振周期解及幅频特性曲线.  相似文献   

7.
本文从小应变,中小转动问题的弹性薄壳一般方程出发,导出用复未知函数表示的非线性的环壳轴对称变形的基本方程,并用摄动方法分別求解了整环壳和开口环壳问题.所得到的结果与其他作者用数值方法得到的结果吻合很好。  相似文献   

8.
一类弱非线性振动问题的插值摄动解法   总被引:8,自引:0,他引:8  
用插值摄动法[1]求解一类有阻尼的弱非线性振动问题。算例表明,当小参数很小时,本文结果和多尺度法的一级近似结果十分接近。当小参数不是很小时(即接近于强非线性振动时),本文结果,仍然相当准确,并优于多尺度法的一级近似结果。  相似文献   

9.
复合载荷作用下具有光滑中心波纹膜片的非线性分析   总被引:2,自引:0,他引:2  
采用轴对称旋转壳体的简化Reissner方程,研究了在复合载荷作用下具有光滑中心波纹膜片的非线性弯曲问题。应用积分方程方法,可以获得膜片的特征关系(载荷-中心挠度关系)。文末给出了实例计算的数值结果。  相似文献   

10.
同伦摄动理论及其应用   总被引:1,自引:1,他引:0  
本文应用同伦技术和摄动技术,提出了一种新的摄动理论。这方法有别于传统的摄动理论,它不依赖于小参数,而是应用同伦技术,构造一个含嵌入参数p∈(0,1)的方程,然后把嵌入参数作为“小参数”,因此这种新方法可以克服传统摄动理论的不足,而又可以充分应用各种摄动方法。其结果显示这种方法简单而有效,并且其一阶近似往往具有很高的精度。  相似文献   

11.
采用轴对称旋转壳体的简化Reissner方程,研究了在均布载荷作用下具有光滑中心波纹膜片的非线性弯曲问题。应用格林函数方法,波纹膜片的非线性边值问题化为了非线性积分方程的求解。为了求解积分方程并防止发散,一个插值参数被引入到迭代格式中。计算表明,当载荷很小时,任何插值参数值均能保证迭代的收敛性,取插值参数值接近或等于1获得较快的收敛速度,而当载荷较大时,插值参数值不能取得过大。绘出了波纹膜片的特征曲线,得到的特征曲线可供设计参考。可以断言,当载荷不大时,特征曲线是近似线性的,随着载荷的增大,特征曲线开始向上弯曲,明显偏离线性。本文中提出的解决方法适应于任意轴向截面的波纹壳体。  相似文献   

12.
We establish the local symmetry group of the dynamically and kinematically exact theory of elastic shells. The group consists of an ordered triple of tensors which make the shell strain energy density invariant under change of the reference placement. Definitions of the fluid shell, the solid shell, and the membrane shell are introduced in terms of members of the symmetry group. Within solid shells we discuss in more detail the isotropic, hemitropic, and orthotropic shells and corresponding invariant properties of the strain energy density. For the physically linear shells, when the density becomes a quadratic function of the shell strain and bending tensors, reduced representations of the density are established for orthotropic, cubic-symmetric, and isotropic shells. The reduced representations contain much less independent material constants to be found from experiments.  相似文献   

13.
By using the fundamental equations of axisymmetric shallow shells of revolution, the nonlinear bending of a shallow corrugated shell with taper under arbitrary load has been investigated. The nonlinear boundary value problem of the corrugated shell was reduced to the nonlinear integral equations by using the method of Green's function. To solve the integral equations, expansion method was used to obtain Green's function. Then the integral equations were reduced to the form with degenerate core by expanding Green's function as series of characteristic function. Therefore, the integral equations become nonlinear algebraic equations. Newton' s iterative method was utilized to solve the nonlinear algebraic equations. To guarantee the convergence of the iterative method, deflection at center was taken as control parameter. Corresponding loads were obtained by increasing deflection one by one. As a numerical example,elastic characteristic of shallow corrugated shells with spherical taper was studied.Calculation results show that characteristic of corrugated shells changes remarkably. The snapping instability which is analogous to shallow spherical shells occurs with increasing load if the taper is relatively large. The solution is close to the experimental results.  相似文献   

14.
Natural Vibrations Of Corrugated Cylindrical Shells   总被引:1,自引:0,他引:1  
A method for determining the natural frequencies and modes of corrugated noncircular cylindrical shells is presented. The influence of the length and amplitude of corrugations on the fundamental frequency of unloaded and axially compressed shells is examined. The difference between the dependences of frequencies and critical loads on shell geometry is shown. The possibility of optimizing shells in frequencies and critical loads is established__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 5, pp. 58–67, May 2005  相似文献   

15.
本文从Krmn非线性基本微分方程出发,提出了将修正迭代法和伽辽金法联合运用,分析了弹性地基上圆底扁球壳在均布荷载作用下周边固定边界条件的非线性动力响应问题,给出了中心振幅与时间t之间关系的二次近似解析表达式;同时还讨论了Winkler地基参数K对中心最大振幅的影响。此外将本文的部分结果和已有文献结果作了比较,二者吻合较好。  相似文献   

16.
An efficient nontraditional scheme of the substructuring method is expounded. It is based on the curvilinear mesh method (CMM) used for analysis of complex shell structures. In forming the stiffness matrix, this approach excludes fully the shell displacement approximation errors. A numerical algorithm that preserves the efficiency of the CMM for shells of arbitrary form is developed. The stress–strain problem for a boxed beam with diaphragms and a cylindrical roof shell is solved numerically. The results are compared with those obtained by other numerical methods  相似文献   

17.
An approach is proposed to solve static problems for corrugated nonthin cylindrical shells applying spline-approximation in the longitudinal direction and a stable numerical method in the circumferential direction. Solutions are presented in the form of plots and tables for isotropic and transversely isotropic shells of constant and variable thickness__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 1, pp. 18–24, January 2005.  相似文献   

18.
本文用初参数积分方程方法,对悬链线波纹壳在均布压力作用下的应力和位移进行了分析,并给出了一个算例。  相似文献   

19.
Consideration is given to three versions of nonlinear strain–displacement relations in the case of small strains and moderately small angles of rotation: (i) relations that neglect rotations about the normal in conformity with the hypotheses of the Donnel–Mushtary–Vlasov theory; (ii) relations, derived from the elasticity equations using Novozhilov's tensor, that exactly allow for rotations; and (iii) relations, proposed by Sanders, that allow for rotations but neglect shear strains. These versions are compared by comparing the solutions of the stability problem for a corrugated cylindrical shell. It is established that the critical loads are close when rotations are allowed for exactly and when Sanders' technique is used  相似文献   

20.
The stress problem for corrugated hollow transversely isotropic cylinders is solved in three-dimensional formulation for certain end conditions. Discrete Fourier series are used to make the problem one-dimensional, which is then solved by the stable discrete-orthogonalization method. Examples of analysis are given__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 3, pp. 62–69, March 2005.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号