卷积型加权残值法求解梁的动力学问题

 利用卷积型加权残值法推导出Gurtin变分原理, 并应用卷积型加 权残值法计算了简支梁的振动、冲击问题, 算例表明此方法是成功的.     

一种薄壳厚壳通用的轴对称曲壳单元

有限元法分析轴对称壳体时，常需区分薄壳和厚壳并选用不同的单元，给计算带来不便．为此，通过对现有的轴对称壳体单元的研究，基于加权残值法，将广义协调条件引入剪应变场，构造了一种挠度和转角各自独立的新型轴对称曲壳单元．算例结果表明，新单元具有很高的精度，既可用于厚壳，也可用于薄壳．该单元可用于轴对称壳体结构的计算分析．     

紧支试函数加权残值法

将紧支函数引入加权残值法中，提出了紧支试函数加权残值法，其数值格式具有和有限元相似的窄带系数矩阵，提高了加权残值法的计算效率．在紧支试函数加权残值的基础上，导出了紧支试函数直接配点法、紧支试函数Hermite配点法和紧支试函数最小二乘配点法的具体格式，并且对几个典型算例进行了分析．与配点法相比，这些方法精度高，稳定性好，而与Galerkin法相比，这些方法效率高．     

有效集法在数学规划加权残值法中的应用

本文研究有效集法在数学规划加权残值法求解微分方程问题中的应用。从理论上和实际应用方面 阐明，对于数学规划加权残值法和线性规划问题，有效集法比常用的单纯形法更简便、易程序化、计算速度更快，因此更适用于数学规划加权残值法求解微分方程问题。     

升阶试函数族在矩形板大挠度问题中的应用

为解决加权残值法求近似解的计算精度问题，将摄动法与加权残值法相结合，首先以板中心挠度为摄动参数进行摄动，将矩形板大挠度非线性偏微分方程组分解为线性偏微分方程组，然后用最小二乘法求解．求解中构造并应用了可以由控制参数，调节的升阶试函数族，计算结果与实验结果基本一致，与以前的研究比较，计算精度明显提高．该方法对于寻求最佳试函数和最佳近似值是一种有效的方法．     

四边固定矩形板大挠度问题的摄动最小二乘解

本文将摄动法与加权残值法相结合,提出了求解大挠度问题的摄动加权法,编制了PWS计算程序,计算了四边固定矩形板在均布载荷下的大挠度问题。算例的结果与实验一致。     

卷积型最小二乘法求解梁的动力学问题

提出了卷积型最小二乘法,并用其计算了不同初始条件和不同边界条件下梁的动力学问题,算例表明,方法概念简单,计算方便,精度高,计算工作量少,卷积型最小二乘法是计算结构动力学问题的一种简单、高效的方法,试函数可以不满足边界条件.     

用加权残值法分析阻尼介质对薄板塑性动力响应的影响

本文应用加权残值法分析阻尼介质对薄板塑性动力响应的影响。文中先以简支圆板在阻尼介质中的运动为例,给出用加权残值法分析塑性动力响应问题的方法及步骤。即先对结构的基本方程进行拉普拉斯变换,然后再利用加权残值法进行求解,计算结果与文(2)中结果一致。文中又以本文方法分析了阻尼介质对简支方板塑性动力响应的影响,并对计算结果进行了讨论。     

数学规划加权残值法在非线性微分方程中的应用

本文研究数学规划加权残值法在非线性微分方程求解中的应用,利用数学规划加权残值法和ＬＰ模理论,把非线性微分方程边值问题转化为一个可微分的无约束非线性优化问题,从而运用成熟稳定的寻优方法求得问题的解。文中数字计算例子表明本文方法可以快速有效地求解非线性微分方程。     

第三届全国加权残值法学术会议在四川召开

中国力学学会计算力学委员会主办的第三届全国加权残值法学术会议于1989年11月21日至25日在四川省峨眉山市西南交通大学科技交流中心举行。会议由中国力学学会计算力学委员会委托西南交通大学岩土工程研究所承办。会前由西南交通大学出版社出版了第三届加权残值法会议论文集,国内外公开发行,共收入论文94篇,其中41篇论文在大会上宣读。 自1986年第二次会议以来,我国加权残值法在理论上和应用上都有了新的发展。在94     

The R-function method used to solve nonlinear bending problems for orthotropic shallow shells on an elastic foundation

The paper proposes a method to solve geometrically nonlinear bending problems for thin orthotropic shallow shells and plates interacting with a Winkler–Pasternak foundation under transverse loading. This method is based on Ritz’s variational method and the R-function method. The developed algorithm and software are used to solve a number of test problems and to study complex-shaped shells. The effect of the shape of shells, the boundary conditions, the stiffness of the foundation, and the load distribution on the behavior of isotropic and orthotropic shells undergoing geometrically nonlinear bending is studied     

基于混合变量条形传递函数方法的圆柱壳屈曲分析

提出了一种分析交各向异性圆柱壳和阶梯圆柱壳稳定性问题的混合变量条形传递函数方法。首先基于Fluegge薄壳理论，通过定义广义位移变量和对应的广义力变量，建立了圆柱壳混合变量能量泛函；然后通过引入条形单元，定义混合状态变量和采用传递函数方法对超级壳单元求解，得到具有多种边界条件圆柱壳屈曲问题的半解析解；最后通过位移连续和力平衡条件，可以得到阶梯圆柱壳屈曲问题的解。理论解推导过程表明此方法在引入边界条件和进行阶梯圆柱壳求解时非常方便。算例分析的结果验证了本方法的正确性。     

U型波纹管大挠度变形的积分方程描述及其迭代算法

采用格林函数法,导出了U型波纹管圆环壳部分和截头扁锥壳部分的非线性的积分方程,其中的四个未知参数由圆环壳和截头扁锥壳的连接条件确定,联合应用梯度法和积分方程迭代法建立了U型波纹管大挠度分析的迭代算法,开发了相应的程序系统,数值结果表明,本文方法具有较高的精度,压缩角对峰值应力和刚度影响十分显著,应用作为波纹管设计的重要参数。     

Numerical and Analytical Approaches to the Stability Analysis of Imperfect Shells

Two new approaches are proposed for the numerical and analytical stability analyses of imperfect shells. One approach is based on the generalized mesh method, whereas the other employs a modified reduced-stiffness method. Both approaches apply to shells with initial geometrical imperfections. Numerical results are compared with experimental data for shells with a single dent. Analytical results are also presented and compared     

Investigation of high elastoplastic straining of shells of revolution under complex tensile and torque loading

A method of the numerical solution of nonlinear unsteady problems of axisymmetric elastoplastic straining of shells of revolution with allowance for torque loading at high strains is proposed. The method is based on the geometrically nonlinear theory of the Timoshenko shells and the plasticity theory with due allowance for combined isotropic and kinematic hardening. The problem is solved with the use of the variational difference method. Results of numerical and experimental investigations of elastoplastic straining of cylindrical shells under proportional and sequential kinematic tensile and torque loading are reported.     

Stress function method in shakedown analysis of axisymmetric shells

A self-equilibrated stress obtained from the stress functions of thin shells is used for the static shakedown theorem as a residual stress. In combination with the finite element method, a linear programming formulation of the shakedown analysis of axisymmetric shells is derived. The physical meaning of the stress function method is clear and its computing amount is small. Some examples of the plates and shells show that the method is reasonable and efficient.The project was supported by the National Natural Science Foundation of China     

Neumann's method for boundary problems of thin elastic shells

The possibility of using Neumann's method to solve the boundary problems for thin elastic shells is studied. The variational statement of the static problems for the shells allows for a problem examination within the distribution space. The convergence of Neumann's method is proven for the shells with holes when the boundary of the domain is not completely fixed. The numerical implementation of Neumann's method normally requires significant time before any reliable results can be achieved. This paper suggests a way to improve the convergence of the process, and allows for parallel computing and evaluation during the calculations.     

Stress-fit applications to experimental shell analyses

The stress-fit method is a procedure for determining complete stress distribution in shells from experimental data. Displacement, slope and shearing-force distributions may also be calculated. The method is applicable to all shell configurations for which closed-form solutions have been formulated and may be applied to certain asymmetrically loaded shells as well as those loaded axisymmetrically. Application to cylindrical and spherical shells is discussed in detail, and the procedure is shown to be verfied experimentally.     

无网格局部Petrov-Galerkin法求解板壳弹塑性大变形

无网格局部Petrov-Galerkin法构造的高阶光滑的形函数非常适合建立板壳结构场函数的逼近函数,是一种比较理想的研究板壳问题的方法。基于Mindlin板壳理论,采用更新拉格朗日原理和大变形条件下场量的无网格表达形式,实现了率型无网格局部Petrov-Galerkin方法对板壳弹塑性大变形的求解,算例分析表明了方法的有效性和较高的分析精度。     

F E M analysis of delamination buckling in composite plates and shells

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