共查询到20条相似文献，搜索用时 171 毫秒
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本文运用ANSYS有限元分析软件对一平面钢框架进行火灾模拟计算,建立了平面钢框架的三维有限元模型,分别求出了一层左端单元和二层左端单元受火条件下钢框架的梁、柱翼缘和腹板随时间变化的温度分布情况。 相似文献
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根据Eringen的非局部弹性理论和克希霍夫薄板理论成功推导出双层粘弹性FGM板在简支状态下考虑表面效应时的双轴屈曲的一般控制方程。利用Navier的方法求得了板系统屈曲荷载的分析解,继而讨论了结构阻尼、介质阻尼,介质的温克尔模量和剪切模量等因素对屈曲荷载的影响。从分析中发现系统的屈曲行为十分依赖非局部作用和表面效应,系统的屈曲特性还跟板厚、介质的剪切模量和温克尔模量有一定的依赖关系。 相似文献
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传统组合梁在采用连续梁体系时中间支座附近承受负弯矩会使上层砼板过早开裂,工字钢下翼缘因此承受较大压力易引起局部失稳.弥补此缺陷的措施是在负弯矩区钢梁下翼缘增设砼板,通过剪力件与钢梁连接,其作用是使钢梁下翼缘"固结"于砼板内,增强钢梁的局部抗稳定能力,即双层砼板组合梁.本文将双层砼板组合梁节段假定为Goodman弹性夹层,利用Abaqus6.5建立双层砼板组合梁空间模型,采用滑移单元slide-plane模拟剪力连接件,重点研究下部剪力件的变化对上层砼板应力的影响.得出了下部剪力度的经济值约为1.0. 相似文献
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机翼梁加筋腹板主要承受剪力,屈曲是其重要的失效模式,临界屈曲载荷是其结构强度的重要表征。在飞机结构设计中合理增加筋条来减小腹板的尺寸,既可以提高腹板的临界屈曲载荷,也可以适当减轻结构重量。文章通过数值计算(有限元非线性分析)结果来说明合理设置加强筋止裂筋对提高梁腹板临界屈曲载荷的贡献。 相似文献
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详细介绍了某水电站岩锚梁载荷试验过程,通过对试验数据的整理分析表明,岩锚梁锚杆应力变化主要是由于围岩二次应力调整及围岩变形引起的,试验荷载本身引起的增量较小。在试验荷载作用下处于弹性范围内,岩锚梁满足设计要求。 相似文献
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本文假设组合箱梁的弯矩M全部由翼板来承担,剪力Q由波形刚腹板来承担,按照考虑剪切变形的Timoshenko梁弯曲理论,推导出考虑波形刚腹板剪切变形的弯曲刚度计算式,在此基础上,将弯矩M按三角级数展开并近似取第一项,利用三角函数导数性质,得到简单的考虑波形刚腹板剪切变形对抗弯刚度折减系数表达式。通过验证模型,验证了这种等效在集中荷载和均布荷载下具有良好的精度。 相似文献
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畸变屈曲作为控制冷弯薄壁卷边槽钢柱承载力的重要模式之一，正逐步受到国内外研究人员的重视。本文针对畸变屈曲的变形特征，通过12根试件在不同连杆布置方式下的轴心受压和偏心受压试验研究，验证在冷弯薄壁卷边槽钢的卷边处设置连杆用以提高其承载力这一方法的有效性．得出了最有效的连杆布置方式。同时，采用有限元软件ABAQUS对试件进行了模拟分析，探讨了初始缺陷、双向偏心等因素的影响。 相似文献
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阐述了压杆弹塑性失稳的ANSYS分析方法，根据弹塑性屈曲问题的切线模量理论，对材料弹塑性段的应力一应变曲线进行直线化处理，利用ANSYS的非线性屈曲分析方法，对活塞杆进行了屈曲分析，其分析结果与理论分析一致。 相似文献
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The calculation of critical buckling loads of planar curved bars, subjected to a general co-planar continuous external load (or a general co-planar terminal loading), leads to the solution of transcendental (nonlinear) equations. In this investigation a new method for the closed-form solution of such types of equations is presented. In particular, the transcendental equation u tan γ cot uγ = 1, corresponding to the buckling problem of a cantilever circular bar of high curvature loaded by two co-planar forces acting along its chord, is solved in a closed-form. Finally, several numerical results are presented, based on the Gauss integration rule. 相似文献
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Two algorithms based on an integral equation formulation of the buckling optimization problem are formulated and implemented. The objective of the optimization is to maximize the buckling load of an elastically restrained column by optimally designing the cross-sectional area subject to a minimum cross-section or maximum stress constraint. The first approach involves solving the resulting integral equations iteratively taking into account the boundary conditions, the optimality criterion and the imposed constraints. In the second approach an iterative finite difference approximation scheme is developed.The column is elastically restrained at both ends which produce the simple support and clamped end conditions for the limiting cases leading to the optimal design of columns under general boundary conditions. The above problems do not have analytical solutions due to the complexity of the boundary conditions, constraints and the optimality conditions necessitating the formulation of computational schemes for their solution. Several numerical results are given and compared with available results in the literature. Moreover the accuracy of the methods is studied by comparing the iterative solutions with finite element ones and with exact results when available. 相似文献
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We present the mathematical model and an artificial neural network method for calculating the buckling load of a beam column with different end conditions. A trial solution of the beam column equation is written as a sum of two parts, in which first part satisfies the boundary conditions and the second part represents the feed forward neural network containing adjustable parameters, weights and biases. We prepared the Error function by using the beam column equation and its boundary conditions, which is used in the back propagation method with deflection term to update the network parameters. It is found that the artificial neural network method is capable for calculating deflection of a beam column as a part of the training process. To ascertain the soundness, efficiency and accuracy of the proposed method the results are compared to the Euler critical load. 相似文献
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新材料和先进加工技术的进步使得钢材的屈服强度不断提高，为了取得更好的经济效益，冷弯钢材的厚度变得越来越薄。作为控制冷弯薄壁型钢承载能力的几种屈曲模式之一，畸变屈曲正逐步受到重视。本文总结了国内外对畸变屈曲研究的主要成果，并对几种常见荷载下的畸变屈曲计算进行了归纳。 相似文献
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高频焊接矩形管生产效率高,抗扭性能好,平面外刚度大,根据需要内部可充填混凝土以提高抵抗局部屈曲的能力,比焊接H型钢的轻钢厂房有更好的经济性。为提高梁柱连接节点的承载力、减小节点变形,需在节点区外包槽钢。本文分析了节点区不同厚度、不同形式外包槽钢和不同的柱内加劲肋设置等对节点强度和刚度的影响,得出了满足刚性连接要求的节点区外包槽钢厚度计算公式。研究了柱加劲肋、螺栓排列、螺栓数目、槽钢宽度和槽钢下伸长度等的影响。建议了箱形柱柱顶与梁上翼缘齐平,槽钢与梁端板等厚,槽钢向上伸出长度以满足安装一排高强螺栓的要求,并设置三角形加劲肋与柱顶盖板和槽钢焊接,箱形柱顶和槽钢内面满焊的节点形式。分析表明这种节点有很高的刚度和强度,能满足刚性连接的要求。 相似文献
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Christos V. Massalas George I. Tzivanidis John T. Katsikadelis 《Journal of The Franklin Institute》1978,306(6):449-455
In this paper, a solution is presented to the buckling problem of a continuous beam resting on a tensionless foundation model that was proposed by Winkler and by Reissner. 相似文献
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The usual use of fractals involves self-similar geometrical objects to fill a space, where the self-similar iterations may continue ad infinitum. This is the first paper to propose the use of self-similar mechanical objects that fill an alloted space, while achieving an invariance property as the self-similar iterations continue (e.g. invariant strength). Moreover, for compressive loads, this paper shows how to achieve minimal mass and invariant strength from self-similar structures. The topology optimization procedure uses self-similar iteration until minimal mass is achieved, and this problem is completely solved, with global optimal solutions given in closed form. The optimal topology remains independent of the magnitude of the load. Mass is minimized subject to yield and/or buckling constraints. Formulas are also given to optimize the complexity of the structure, and the optimal complexity turns out to be finite. That is, a continuum is never the optimal structural for a compressive load under any constraints on the physical dimension (diameter). After each additional self-similar iteration, the number of bars and strings increase, but, for a certain choice of unit topology shown, the total mass of bars and strings decreases. For certain structures, the string mass monotonically increases with iteration, while the bar mass monotonically reduces, leading to minimal total mass in a finite number of iterations, and hence a finite optimal complexity for the structure. The number of iterations required to achieve minimal mass is given explicitly in closed form by a formula relating the chosen unit geometry and the material properties. It runs out that the optimal structures produced by our theory fall in the category of structures we call tensegrity. Hence our self-similar algorithms can generate tensegrity fractals. 相似文献