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楔形变截面压杆的弹塑性稳定 总被引:2,自引:0,他引:2
研究了楔形变截面压杆平面内弹塑性弯曲失稳。提出了以大头截面为计算截面的压杆稳定性计算公式 ,给出了配套的变截面压杆计算长度系数公式和表格。对变截面压杆与等效的等截面压杆的弹塑性工作性能进行了比较 ,发现后者总是在悬臂柱的固定端截面开始出现塑性 ,而变截面压杆的塑性区在离固定端一定高度的地方先出现 ,这一差别导致弹塑性失稳的变截面压杆比等效的等截面压杆的承载力要高 相似文献
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根据变截面压杆截面的变化规律,基于势能驻值原理,利用能量法推导出了变截面压杆稳定临界力的计算公式.该方法计算方便、精度高,适合于各种截面变化规律的压杆,易于被工程设计人员掌握. 相似文献
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建筑结构压杆稳定截面设计的直接荷载法 总被引:1,自引:0,他引:1
本文通过对建筑结构压杆稳定条件及“欧拉公式”的适用范围,对压杆稳定在荷载作用下的受力分析,提出压杆稳定截面设计的直接荷载法,并讨论了压杆稳定截面设计的基本思路及应用。 相似文献
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本文应用能量法、推导出了两端铰支变截面压杆临界截荷,放大系数f的计算公式,从而,可简便地利用等面匀质压杆的欧拉公式,乘以放大系数f求出两端铰支变截面压杆的临界载荷值。 相似文献
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为了研究轴心受压等肢角钢绕截面最小轴弯曲屈曲特性,建立了一种分析方法。基于压杆无应力态下弧长不变原理求得压杆弧长状态方程。在弹性受压阶段,基于压杆中点力矩平衡微分方程求得应力-挠度相关方程。在弹塑性受压阶段,基于角钢压杆中点截面应力分布列出力与力矩平衡方程,从而导出应力-挠度-截面弹性区高度的相关方程;基于压杆中点应变所产生的曲率与轴线函数微分所求得的曲率相等关系求得截面弹性区高度表达式。最后,通过上述基本方程的联立求解,求得角钢压杆在弹性及弹塑性受压阶段的本构关系方程。利用所提出的本构关系方程,研究等肢角钢轴心压杆的屈曲特性。研究结果表明:此方法合理准确,能够有效预测等肢角钢轴心压杆的屈曲特性。 相似文献
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在结构稳定性计算中,常常必须计算压杆的临界荷载,其中变截面压杆的临界荷载计算比较复杂。本文讨论用数学模拟方法计算变截面压杆的临界荷载,其计算结果表明,与精确值相比误差相对较小。 相似文献
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通过对等截面压杆临界荷载进行分析,提出了能量法和图乘法相结合的方法,对上端铰支、下端固端压杆的稳定性进行了分析,指出该方法误差很小,可以忽略不计,能够应用于其他各类压杆。 相似文献
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Considering the structural characteristics of transmission towers, four sections of cold-formed angles with different slenderness
ratios and constrained types were selected for the experimental and numerical study. Experiments and finite element analysis
for the ultimate loads of the compression cold-formed angles were carried out. The finite element model well predicts the
buckling behaviour of the cold-formed members. For the axial compression members, the load-strain curves as well as the ultimate
loads were analyzed, and the experimental ultimate loads were compared with those of calculated by the applicable standards.
It shows that the applicable standards aren’t adaptive to the strength design of the compression cold-formed members in transmission
towers. Through the analysis of the experimental and FEA results, the fitting curve of the stability coefficients for the
cold-formed members in transmission towers was determined. The ultimate loads calculated by the fitting curve are well agreed
with the experimental values, especially for the members with relatively low slenderness ratios. Some modification suggestions
were proposed for the calculation of the ultimate load for the axial compression cold-formed angle. Experimental analysis
on the cold-formed members of the other five constrained types was completed, and the modification formulas of the slenderness
ratios for members of different constrained types were obtained. 相似文献
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文中对所收集的GFRP轴心受压构件稳定性的研究进行综述,归纳出GFRP轴心受压构件的失稳模式.对GFRP轴心受压构件承载力的计算方法进行总结,结合已收集的相关实验数据分析得出这些计算方法的适用条件并对现有计算方法进行修正. 相似文献
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Gunnar Mller 《Bautechnik》2007,84(5):329-334
Determination of ultimate loads for compression members in timber constructions. The design of compression members in timber constructions has to consider the increasing stress due to the non‐linear behaviour of the members. The determination of the ultimate load of compression members requires the consideration of non‐linear geometric behaviour, if the bending moments increase more than 10% in relation to the linear theory. In the German timber design code, DIN 1052 [1], two methods of calculation are suggested. The second method uses geometric non – linear theory (theory second order) for calculation of the ultimate load. According to DIN 1052 the load carrying capacity can be determined without reducing stiffness parameters using the modification factor. The calculation methods for compression members according to DIN 1052 are compared and differences between them are discussed. A calculation with identical results for the ultimate loads using either the first or the second method is proposed. 相似文献
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碳纤维加固具有自重轻、抗拉强度高、易施工、耐久性好等优点,被广泛应用于加固钢筋混凝土结构,并开始推广应用于加固钢结构。采用碳纤维加固钢压杆,对其稳定承载力进行简化分析,并推导出加固后钢压杆临界荷载和稳定系数的计算公式。 相似文献
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本文对哈特福德城体育馆网架结构中的受压弦杆和腹杆作了分析,发现原设计者只计及了杆的弯曲屈曲,但是因支撑体系在杆的中点存在连接偏心,杆将发生弯扭屈曲,经计算15种压杆的弯扭屈曲荷载均远小于弯曲屈由荷载,致使屋盖结构塌落. 相似文献
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Member imperfections for verifications against lateral buckling of compression members. The main focus of the article is on investigations about the lateral buckling of compression members made of hot‐rolled I‐profiles. First of all the general load‐carrying behaviour is clarified. Afterwards necessary member imperfections are determined in case of pure normal force or combined bending stress. The results are compared to the values of the actual design codes. For members with pure compression force and buckling about the strong axis new member imperfections are specified. By these values up to 12% higher ultimate loads as up to now can be utilized. 相似文献
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提出适用于非线性材料的广义梁理论屈曲荷载计算方法,并对不锈钢薄壁受压构件屈曲荷载进行计算验证。通过定义材料非线性应力应变关系和瞬时弹性模量,对传统线弹性广义梁理论进行修正,建立非线性材料薄壁构件受压屈曲荷载计算方法,推导不锈钢薄板受压局部屈曲、冷弯薄壁不锈钢卷边槽形柱畸变屈曲及箱形不锈钢长柱弯曲屈曲荷载计算公式,并与既有试验数据对比。经验证,线弹性分析方法不适用于不锈钢材料;提出的修正GBT法具有较高精度,且本构关系采用变形法则结果偏于安全,可用于不锈钢等非线性金属材料薄壁构件受压屈曲荷载的确定,为研究和设计提供理论指导。 相似文献
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基于箱形截面具有双轴对称、抗弯扭刚度大的特点,提出将冷弯∑形截面两两翼缘相对,并将其卷边焊接形成一种新型冷弯箱形组合截面——DS。应用非线性有限元方法分析新型截面构件在轴压、弯矩及压弯荷载作用时的诸如屈曲模式、承载力、刚度、延性及相关曲线等方面力学性能。同时,还对相同参数的新型截面构件与C形截面构件的单位承载力耗钢量进行比较。分析表明:新型截面构件在承受轴压力时具有高承载力及较高的截面模量,截面加劲充分而使子板件局部屈曲不易出现等力学性能优势。特别适宜承受轴压荷载,同时也适宜承受弯矩和压弯荷载的作用。轴压构件的单位承载力耗钢量一般仅为相同参数C形构件的50%左右,经济效益明显。新型箱形组合构件适于深入试验研究并合理应用于实际工程。 相似文献