共查询到18条相似文献，搜索用时 187 毫秒
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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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为解决冷弯薄壁型钢易失稳和产生局部屈曲等问题,本文提出冷弯薄壁方钢管轻质混凝土柱(LCFCSTC),以试验验证为基础,利用ABAQUS有限元软件对LCFCSTC进行非线性有限元分析,对比分析空钢管柱与LCFCSTC的承载能力;同时,研究长细比、钢管厚度和轻质混凝土强度对LCFCSTC性能的影响,分析典型试件的荷载位移与荷载侧向挠度关系曲线、破坏模式和应力分布等。研究结果表明：在冷弯薄壁方钢管内填充轻质混凝土能有效抑制空钢管产生局部屈曲并提高柱子承载力;LCFCSTC均发生整体失稳破坏,承载力随着轻质混凝土强度等级和钢管厚度增大而增加,随着长细比增加,构件的承载力逐渐减小。基于AISC-LRFD规程和Perry-Robertson公式推导出LCFCSTC承载力计算公式,该公式能够很好地计算LCFCSTC的稳定承载力。 相似文献
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近年来冷弯薄壁型钢作为一种高效、经济型材受到国内外工程界的普遍关注,冷弯薄壁型钢在建筑业中的应用也日趋广泛。本文简要介绍冷弯薄壁型钢结构的特点、类型,并列举了冷弯薄壁型钢结构在实际工程中的应用。 相似文献
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为了研究装配式建筑箱板式钢结构抗震性能,选择试验对象及其材料参数,设计与制作装配式建筑箱板式钢结构试件,确定试验地震波,设置试验方案、步骤和加载制度,分析试件滞回、位移时程、骨架抗震性能。试验测试结果显示：在高轴压比下,试件出现了刚度退化、承载力降低、水平极限承载力下降、延展性变差等现象。由此表明,高轴压比下,试件受到地震波作用时,会产生低周反复加载过程,使试件处于三向受压失衡状态,破坏试件结构。因此,需要增加试件箍筋的布置密度,改变钢结构的初始刚度,约束试件核心混凝土,提高钢结构水平承载力,使试件处于三向受压平衡状态,增强装配式建筑箱板式钢结构抗震性能。 相似文献
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《黑龙江科技信息》2018,(31)
为研究PVC管及螺旋箍筋-PVC管组合核芯约束钢筋混凝土方形短柱的轴心受压承载性能,设计了7个PVC管、12个螺旋箍筋-PVC管组合核芯约束钢筋混凝土方形短柱以及1个普通钢筋混凝土方形短柱进行轴心受压试验。试验过程观察了试件的受力过程及破坏形态,获取其极限承载力的力学指标,分析了核芯区面积、箍筋直径和箍筋间距对试件轴压性能的影响规律。研究表明:RC-PVC柱核芯区面积的增加,使试件极限承载力呈上升趋势,随着箍筋间距的减小,极限承载力逐渐提高,但核芯区面积过小或方箍间距过大都会使试件极限承载力低于普通钢筋混凝土方形短柱。RC-SS-PVC柱核芯区面积的增加,有效提高了试件的极限承载力,但在螺距较大的情况下,提高幅度有限;当螺旋箍筋间距小于80mm时,试件极限承载力随螺旋箍筋直径的增加而减小,当螺旋箍筋间距大于80mm时,试件极限承载力随螺旋箍筋直径的增加而增大。 相似文献
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雨蓬、阳台和挑檐等悬挑构件的受力特点随着结构类别、支承条件、布置、构造等的不同而不同,总的情况是:承载能力方面有受弯、受剪和受扭计算;有时还需要验算梁支座下面的砌体局部受压承载力。 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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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
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局部荷载作用下工字形梁腹板的弹性屈曲分析 总被引：1，自引：0，他引：1
钢结构工程中经常遇到一定宽度的均布荷载通过翼缘传递到腹板上的情况，这种荷载称为局部荷载。本文对工字形梁腹板在局部荷载作用下的弹性屈曲进行了有限元分析，得到了不同宽度的荷载作用下工字形梁腹板的弹性屈曲系数，着重考虑了翼缘的转动约束对腹板屈曲的影响。通过数据拟合得到了物理意义明确、精度很高的计算公式。 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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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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纵向框架支撑有两个主要作用:抵抗水平力和保证框架纵向刚度。从整体稳定性角度,考虑交叉支撑和柱顶横系杆的相互影响:通过研究理想体系得到支撑的刚度要求;考虑实际框架中构件初始缺陷,得到水平和竖向荷载共同作用下支撑体系的强度要求。可以发现支撑为保持框架稳定性的承载力要求和抵抗水平力的承载力要求不能直接叠加,水平力降低了框架的抗侧刚度,增大了对支撑的承载力要求。拟合得到水平和竖向力共同作用下支撑承载力要求的计算公式。 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