共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
在等温小变形弹塑性内时本构方程偏量形式的基础上,导出了适用于大位移、小应变分析的弹塑性内时本构方程。并导出了带有初始几何缺陷的非线性弹塑性问题的有限元方程。文中给出的算例表明本方法是可行有效的。 相似文献
3.
Journal of Elasticity - Deployable structures can realize the transformation from a folded configuration to a deployed configuration to satisfy the requirements of applications. They have been... 相似文献
4.
L. B. Lerman 《International Applied Mechanics》2000,36(9):1212-1217
The characteristics of the stress–strain state of thin-walled structural elements are determined in the case where dynamic boundary loads or displacements described by pulse functions are specified. A general scheme for realization of the method of natural-mode expansion is stated as applied to differential equations with unknown functions of one spatial coordinate and time. Theoretical relations for rods, plates, and shells are given. The potential of the approach developed is illustrated by solving specific problems 相似文献
5.
A multifrontal method is proposed for solving large-scale finite-element problems with a symmetric stiffness matrix. This approach is based on node ordering rather than element ordering as in the traditional frontal or multifrontal methods. This allows us to employ the efficient well-known ordering techniques such as the minimum-degree algorithm or the nested dissection method. A thin-walled cylindrical shell with massive ribs is considered as an example. The efficiency of the method proposed is illustrated against the classical skyline and aggregation multilevel conjugate-gradient iterative solvers 相似文献
6.
Some Issues of Continuum Mechanics and Mathematical Problems in the Theory of Thin-Walled Structures
Consideration is given to some issues of continuum mechanics and mechanical problems arising in the theory of thin plates and shells. The main research areas are analyzed. The results obtained in the linear and nonlinear theories of plates and shells are reviewed and some open issues and unsolved problems of those theories are formulated. 相似文献
7.
Abstract The imperfections in the form of initial displacement in structural columns are important factors to be reckoned with. To investigate the effect of imperfections and to obtain the results of general valadity, imperfections in columns should be considered as random in nature. In this paper, the effect of imperfection on column behavior and load carrying capacity is examined. The imperfections are modeled by a stochastically stationary random process with a known autocorrelation function. The results for the expected reduction in column capacity and the bending moments due to imperfection are obtained. The problem of lateral bracings, provided in columns to prevent buckling in their weaker planes and thereby increase their load carrying capacities, is also examined probabilistically: the effect of random initial displacements on the strength and stiffness requirements of a bracing is investigated. 相似文献
8.
9.
10.
ABSTRACT Optimal design problems for flexural systems with a nonlinear constitutive law are considered, in the presence of constraints on displacements. A general nonlinear holonomic moment-curvature relationship is assumed and a direct variational method is applied in order to obtain optimality criteria. Accordingly, a general method of solution is proposed and some examples are solved. 相似文献
11.
为高效模拟空间效应显著的结构在关键局部的损伤,本文研究建立了以损伤分析为目标的空间网格多尺度模拟方法.首先基于变形协调法和内力平衡法,研究了空间网格多尺度建模中的跨尺度界面连接方法,对比分析了两种界面连接合理性.以三跨连续刚构混凝土箱梁在地震载荷下的损伤为分析案例,验证了空间网格多尺度模型在结构损伤分析中的可行性及其在计算效率上的优越性.分析结果表明:空间网格多尺度模型可以精确模拟结构的静力效应和动力特性;空间网格多尺度模型既考虑了结构空间效应,又可以高效分析箱梁结构局部易损部位的损伤演化过程,从而为空间效应显著的结构损伤分析提供了更为实用精细的计算模拟方法. 相似文献
12.
空间柔性结构受太阳热流冲击而诱发的振动是导致航天器失效的典型模式之一,准确预测结构热致振动的响应及稳定性是卫星设计的基础.针对常见的中心舱体与附属薄壁杆件组成的空间结构,提出了考虑刚-柔耦合、耦合热弹性和耦合热-结构三重耦合效应的热致振动分析理论模型.其中,刚-柔耦合是指舱体姿态角、顶端集中质量转动与柔性附件运动的耦合;耦合热弹性是指应变率与温度场的耦合;耦合热-结构是指舱体转动及结构变形与薄壁杆件吸收太阳热流的耦合.基于热弹性理论和Lagrange方程,推导了传热和运动的耦合方程;采用La-place变换方法并使用Routh-Hurwitz稳定判据推导了稳定性边界方程.结果表明,该模型能够更为准确的给出热致振动响应及稳定性预测. 相似文献
13.
14.
15.
S. Kaliszky 《基于设计的结构力学与机械力学》2013,41(2):195-210
ABSTRACT The elements of a structure whose forces and/or displacements are limited by prescribed conditions are called “conditional joints.” This paper deals with mechanical and mathematical models of conditional joints and shows that their behavior can be characterized by relationships similar to the constitutive equations of ideal plastic and ideal locking materials. It is shown that the analysis of limit states and state changes of structures with conditional joints may also be carried out by means of theorems which are known in the theory of structures of ideal plastic and ideal locking materials. 相似文献
16.
17.
18.
本文扼要分析了以有限元方法为基础的结构分析软件及其辅助系统─—智能化前端系统和模型化系统;然后结合黑板结构和真值维护系统,建立了一个综合模型化、数值求解和对数值结果的解释评价于一体的、基于知识的新型结构分析系统的概念模型;最后,基于有限元软件环境──SEFEM,针对一类简单的结构系统,用语言实现了一个上述模型的简化系统──KBsAP。 相似文献
19.