共查询到18条相似文献,搜索用时 46 毫秒
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在现有结构力学教材中,桁架内力的计算方法大体上可以分为:结点法、截面法及根据几何分析采取的某种方法,但是根据几何分析而采取某种方法的讨论较少. 本文作者根据多年教学经验,提出了桁架可根据几何构造特点而采取适当的方法——简支梁法及三铰刚架法,另外对结点法也进行了进一步的讨论. 相似文献
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求超静定结构精确影响线方程的简捷方法 总被引:1,自引:0,他引:1
本文提供了一种确定超静定结构精确影响线方程的方法,而且用的数学手段非常简单,无论是在结构力学教学中还是在有关的工程实际中都是一种值得提倡的方法. 相似文献
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具有随机拉索刚度的预应力钢桁架随机内力摄动分析 总被引:2,自引:1,他引:2
本文在建立拉索式预应力钢桁架基本计算理论的基础上,考虑到拉索刚度的随机性,推导了拉索式平面预应力钢桁架随机内力摄动分析的一般公式及敏度分析式,并给出了算例。为进一步进行预应力钢桁架可靠性分析奠定了基础。 相似文献
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IntroductionWhenastaticallyindeterminatetrusshasalowerloadcapacityowingtothetremendousdifferenceofinternalforcesofbars,itdoesn’tlayingoodworkingstate.Toincreasethecapacity ,cross_sectionalareasofelementsareoptimizedbytheprogrammingmethodandthecriterion… 相似文献
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随机拉索刚度预应力空间钢桁架随机内力摄动分析 总被引:4,自引:2,他引:4
基于已建立的拉索式平面预应力钢桁架基本理论 ,考虑到拉索刚度的随机性 ,得到了拉索式空间预应力钢桁架随机内力摄动分析的一般公式及敏度分析式 ,给出了空间预应力钢桁架随机内力统计特性计算表达式。为进一步进行空间预应力钢桁架可靠性分析奠定了一定的理论基础。最后针对工程中常见的三角形立体钢桁架 ,给出了算例 相似文献
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Behrooz Farshi Ali Alinia-ziazi 《International Journal of Solids and Structures》2010,47(18-19):2508-2524
This paper describes a new approach to optimum weight design of truss structures. The force method is incorporated in an optimization algorithm based on the method of center points. Design variables are the member cross-sectional areas and the redundant forces evaluated for each independent loading condition acting on the structure. The optimization method utilizes the largest hyperspheres inscribed within the feasible space. The method of hyperspheres has been enhanced here to handle the compatibility equality constraints as well. By including the analysis step in the optimization cycle there is no longer the need to perform separate structural analyses thus saving computation time. The viability and efficiency of the proposed method are demonstrated for truss structures subject to multiple loading conditions and constraints on member stresses, nodal displacement and minimum gage. Numerical results are compared with those reported in the literature. 相似文献
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The aim of this paper is to give the title theory of shearable plates a precise and exact position with respect to three-dimensional linear elasticity. We assume that the Reissner-Mindlin representation of the displacement field hold in a 3-D body in the shape of a plate, and discuss how a constitutive response consistent with such a representation should be chosen. We find that the Reissner-Mindlin plate theory results from mere integration over the thickness of the equilibrium equations of a cylindrical body made of a linearly elastic material which is both transversely inextensible and transversely isotropic.
Sommario Scopo di questo articolo è fornire una deduzione esatta, nell'ambito dell'elasticità lineare tridimensionale, della teoria delle piastre deformabili a taglio menzionata nel titolo. Ammesso che la rappresentazione di Reissner-Mindlin per il campo di spostamento valga in una regione tridimensionale a forma di piastra, si discute come scegliere la risposta costitutiva in maniera coerente con quella rappresentazione. Si trova che la teoria delle piastre di Reissner-Mindlin si ottiene per semplice integrazione sullo spessore delle equazioni di equilibrio di un corpo cilindrico che sia costituito di un materiale linearmente elastico tanto trasversalmente inestensibile che trasversalmente isotropo.相似文献
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The nominal force method for truss geometry and topology optimization incorporating stability considerations 总被引:1,自引:0,他引:1
This paper presents a computationally efficient method for truss layout optimization with stability constraints. Previously proposed approaches that ensure stability of optimal frameworks are first reviewed, showing that existing studies are generally restricted to topology optimization. The present contribution aims to generalize the approach to simultaneous geometry and topology optimization. A lower-bound plastic design formulation under multiple loading will serve as basis for this purpose. The numerical difficulties associated with geometrical variations are identified and the parametrization is adapted accordingly. To avoid nodal instability, the nominal force method is adopted, which introduces artificial loading cases to simulate the effect of geometric imperfections. Hence, the truss systems with unstable nodes are eliminated from the set of optimal solutions. At the same time, the local stability of structural members is ensured via a consistent local buckling criterion. This novel formulation leads to optimal configurations that can be practically used for the preliminary design of structural frameworks. Four applications illustrate the impact of stability constraints on the solution. The importance of geometry optimization is also pointed out by comparing with results that would be unattainable by topology optimization only. 相似文献
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The breakdown of a liquid jet is commonly considered as an effect of the surface tension. However, essential aspects of the boundary wave amplification and the final disintegration of velocity modulated jets can be explained by non-linear travelling time effects, which are of purely kinematic nature. The experiments are carried out on jets with radii between 1.2 to 2.5 mm and Weber numbers between 17 to 200. The experimental results are compared with a theoretical solution which neglects the surface tension. 相似文献