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蜂窝梁是腹板开孔钢梁的一种,由于其结构合理、经济美观,已被广泛应用于工业与民用建筑、桥梁及轮船等多个领域。本文借助有限元分析软件ANSYS对六边形孔蜂窝梁腹板的屈曲性能进行了分析,求出了单孔、双孔以及多孔腹板在纯弯和纯剪作用下的屈曲模态和屈曲系数,拟合了相应的计算公式,并最终确定了腹板的高厚比限值,可供有关设计参考。 相似文献
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蜂窝板夹芯面内弹性模量的理论分析 总被引:1,自引:0,他引:1
蜂窝芯材的弹性模量的确定是夹层结构设计的基础,文章通过3D有限元方法与以往以Eule,梁理论为基础的金属蜂窝夹芯板的等效弹性模量的计算理论进行比较分析,结果表明在t/l相对较小的情况下,用W—K公式较为合适。并结合算例证实了夹芯等效弹模对整板面外刚度的贡献是较小的。 相似文献
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以混凝土为基体材料,将短切形状记忆合金(SMA)纤维和钢纤维分别掺入到混凝土中制备得SMA纤维智能混凝土材料和钢纤维智能混凝土材料。通过对不同的纤维的种类和掺量下的混凝土材料压缩、弯曲和劈裂试验,对SMA纤维智能混凝土材料的力学性能进行了实验室分析。结果表明,与纯混凝土材料相比,SMA纤维与钢纤维智能混凝土材料的抗压、抗弯和抗剪切性能明显提高;当SMA纤维体积掺量为1%时,其相应的力学性能较纯混凝土材料高30%~50%;当混杂体积掺量为2%时,其力学性能较1%时高20%~40%,而当SMA纤维体积含量为3%时,其力学性能相较前两者均降低;SMA智能混凝土材料的力学性能低于相同掺量的钢纤维混凝土材料。 相似文献
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利用形状记忆合金(Shape memor yalloy,简称SMA)的形状记忆效应,配制智能混凝土连续梁。运用试验方法研究SMA智能混凝土梁自修复特性的规律及其影响因素,并分析SMA对连续梁的过大变形及裂缝的修复机理。研究结果表明:预先配置的SMA能够显著提高混凝土梁的刚度;通电激励加热的方法,SMA钢筋能够提供显著的恢复力,有效减小梁的挠度和裂缝宽度;增加合金的总截面面积,即提高SMA丝的配筋率,可提高合金对混凝土梁的驱动效果;在混凝土梁中配置受拉钢筋,虽然可以提高梁的承载能力,但钢筋的塑性变形对SMA梁的变形恢复又起到阻碍作用,会影响梁的修复效果。 相似文献
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本文对一国产NiTi合金棒进行了单轴拉伸试验,并对试验结果进行了统计与分析.总结了影响NiTi合金力学性能的几种主要因素(荷载循环次数、加载频率和应变幅值)及其变化特点。 相似文献
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介绍了形状记忆合金的基本概念及特性,对形状记忆合金在建筑领域的实际应用现状进行了介绍,提出了形状记忆合金应用方面需要解决的问题,对形状记忆合金未来在建筑领域的应用进行了展望。 相似文献
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针对形状记忆合金具有形状记忆效应、超弹性效应和高阻尼特性,利用其超弹性制成的形状记忆合金阻尼器性能优良的耗能减振装置,可以有效地控制结构的动力响应.本文采用ANSYS通用有限元软件,分别建立无阻尼器混凝土框架结构和在相应框架结构各层角点处加形状记忆合金阻尼器两种不同的模型,进行模态分析,再数值模拟加载地震波载荷作用下结构的瞬态动力响应.模态分析结果表明,形状记忆合金阻尼器作为一种记忆和超弹性材料对混凝土框架结构具有良好的减振效果,与理论结果一致.在加阻尼器的单元上,固有频率增大,刚度增大,整体框架结构刚度矩阵减小,同时,通过调整阻尼器的位置,可以明显改变刚度大小,说明阻尼器具有明显的耗能减振效应.瞬态分析计算结果表明,加形状记忆合金阻尼器模型各层位移时程曲线都有不同程度的减小,振幅也有不同程度的衰减;其中位移最大值比无阻尼器模型减小了42%,振幅衰减了31%.但跟其他粘弹性阻尼器比较,形状记忆合金阻尼器作为一种优质高价材料,在混凝土框架结构中的减振效果无明显优势.通过对计算结果的分析,预计该阻尼器适用于大变形钢结构体系. 相似文献
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讨论了形状记忆合金的力学性能,综述了这种全新功能材料的行为特点、本构关系及其在工程中的应用,并简要介绍了它在应用中存在的问题和改进方法. 相似文献
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José Sepúlveda Ricardo Herrera Mauricio Sarrazin 《Journal of Constructional Steel Research》2008,64(4):429-435
This study presents the details of an experimental investigation on a prototype partially restrained connection using copper-based shape memory alloy (SMA) bars. The proposed configuration consists of an end-plate connection between a rectangular hollow structural steel beam and a wide flange steel column, where four CuAlBe () bars, in austenitic phase, are used to prestress the end-plate to the column flange. A physical model of the connection was tested by applying a controlled cyclic displacement history at the tip of the beam with two different characteristic frequencies of 0.25 and 1 Hz. Potentiometers and load cells were used to measure strains and stresses in the bars and the displacement and load applied at the beam tip. Similar bars, with the same thermal treatment, had been previously tested in cyclic tension at several nominal strains and frequencies, showing superelastic behavior for deformations up to 2.3% strain. In static tensile tests, the fracture strain was approximately 8%, with a transgranular fracture mechanism. The equivalent damping ratio for the single bar test increases for larger strains, being 6% for a 2.3% strain. The beam-column connection also exhibited superelastic behavior, a moderate level of energy dissipation, and no strength degradation after being subjected to several cycles up to 3% drift. Finally, a set of numerical simulations are conducted to compare the performance of a rigid steel frame and a partially restrained frame with SMA connections using a three-story benchmark structure. 相似文献
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形状记忆合金橡胶是一种具有复杂多孔结构的隔振和减振阻尼材料,根据其微观结构进行层状分解,结合试块压缩刚度非线性特征得到其力学本构模型。通过引入微曲梁接触对单元,建立模型物理量与材料细观及工艺参数之间的关系,得到形状记忆合金橡胶基本单元的接触刚度;由试件非线性刚度分析得到加载、卸载过程中材料内部微曲梁接触点数量的变化,进而建立形状记忆合金橡胶层状压缩本构模型。结果表明:该模型可以考虑形状记忆合金橡胶的材料参数、加工工艺参数以及加、卸载过程中静摩擦力和滑动摩擦力的影响,更接近形状记忆合金橡胶内部微弹簧线匝的受力状态;参数分析结果表明,形状记忆合金橡胶的弹性模量随着名义密度、形状记忆合金丝直径和摩擦系数的增大而提高。 相似文献
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This paper focuses on introducing and investigating the performance of a new passive seismic control device for cable-stayed bridges made with shape memory alloys (SMAs). The superelasticity and damping capability of SMAs is sought in this study to develop a supplementary recentering and energy dissipation device for cable-stayed bridges. Three-dimensional long-span bridge model, including the effect of soil-structure interaction is developed and utilized in the study. SMA dampers are implemented at the bridge’s deck-pier and deck-tower connections. The bridge is subjected to three orthogonal components from two historic ground motion records. The effectiveness of the SMA dampers in controlling the deck displacement and limiting the shear and bending moment demands on the bridge towers is assessed. Furthermore, a study is conducted to determine the sensitivity of the bridge response to the hysteretic properties of the SMA dampers. The analytical results show that SMA dampers can successfully control the seismic behavior of the bridge. However, the effectiveness of the new dampers is significantly influenced by the relative stiffness between the dampers used at the deck-tower and deck-pier connections. The results also show that the variation in the SMAs’ strain hardening during phase transformation has a small effect on the bridge response compared to the variation in the unloading stress during reverse phase transformation. 相似文献
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B. Asgarian S. Moradi 《Journal of Constructional Steel Research》2011,67(1):65-74
In this paper, the seismic performance of steel frames equipped with superelastic SMA braces was investigated. To do so, buildings with various stories and different bracing configurations including diagonal, split X, chevron (V and inverted V) bracings were considered. Nonlinear time history analyses of steel braced frames equipped with SMA subjected to three ground motion records have been performed using OpenSees software. To evaluate the possibility of adopting this innovative bracing system and its efficiency, the dynamic responses of frames with SMA braces were compared to the ones with buckling restrained braces. After comparing the results, one can conclude that using an SMA element is an effective way to improve the dynamic response of structures subjected to earthquake excitations. Implementing the SMA braces can lead to a reduction in residual roof displacement and peak inter-story drift compare to the buckling restrained braced frames. 相似文献
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钢结构在长期服役过程中,受荷载和环境作用,可能发生结构损伤及性能退化。形状记忆合金(shape memory alloy,SMA)因其特殊的形状记忆效应,可以为钢结构施加预应力,提升结构疲劳性能。以形状记忆合金补强的含损伤钢板为分析对象,采用线弹性断裂力学对补强后产生的钢板疲劳性能进行理论分析。与已有研究中的试验结果相比,钢板的疲劳寿命与试验结果最大相差不超过10%。同时,采用理论模型展开参数分析,研究初始损伤程度和SMA受温度作用产生的恢复应力对补强体系的影响。结果表明:对于不同的初始损伤程度,SMA均能够发挥很好的补强作用;经SMA补强后,钢板的疲劳寿命最大可提高362%;当SMA产生的恢复应力大于200 MPa时,可降低加载时钢板实际承担的应力幅,延缓裂纹扩展。 相似文献