锁铆连接柱面组合网壳的承载力试验研究

Experimental Study on Bearing Capacity of Locking Riveting Connection Cylindrical Composite Reticulated Shell

铝合金具有密度小、耐蚀性好、易加工、比强度高、成型方便等优点,铝合金的密度约为普通钢材密度的1/3,而强度与常规的钢材刚度相当,因此铝合金结构可以获得更大的跨度,受到越来越多建筑师和结构工程师的关注与青睐。为了充分发挥铝合金蜂窝板轻质高强的优势,克服铝合金网壳弹性模量较低的缺点,提出了一种新型的铝合金蜂窝板柱面组合网壳结构。该结构由铝合金蜂窝板和铝合金网壳通过锁铆连接而成,以达到铝合金蜂窝板和铝合金网壳协同工作的目的。为此设计并制备了尺寸为4400 mm×1530 mm×1100 mm的柱面网壳结构,并对其进行了承载力试验,探究了柱面组合网壳的受力特点及破坏机理。在考虑双重非线性以及失稳影响的基础上,对柱面组合网壳进行非线性有限元分析,将分析结果与承载力试验结果对比,验证了有限元分析方法的可靠性。结果表明:组合网壳板-杆之间破坏时连接件主要形式为跨中短跨处抽芯铆钉被剪断,边跨由于铝合金翘曲导致抽芯铆钉拉断,锁铆连接件周围有板件错动趋势,但并未破坏;铝合金杆件最终破坏形式包括铝合金杆件在跨中受力最大处发生沿开孔薄弱处断裂,边跨受压屈曲,铝合金蜂窝板在杆件变形较大处也发生了脱胶现象;在加载点位移为30 mm之前,试件处于弹性阶段,之后进入弹塑性阶段、柱面网壳的非线性行为主要由铝合金杆件与蜂窝板之间的锁铆连接性能决定。柱面组合网壳试件的承载力为6951 N,随着位移的增加,荷载持续降低。考虑双重非线性的有限元分析模型可以有效地模拟组合网壳在弹塑性阶段的受力性能,而考虑失稳后能较好地模拟组合柱面网壳失稳后的变形及受力性能。所提出的有限元分析方法能较精确地模拟柱面网壳的荷载-位移曲线,计算效率高、收敛性好,极限承载力误差在2%左右。锁铆连接集开孔、成型于一体,只需定位便能利用锁铆连接工具将锁铆成型,加工效率最高,成型质量有保证,稳定性优于传统机械的连接,未来可形成“流水线”生产,提高建筑工业化程度。

Aluminum alloy has many advantages such as low density,good corrosion resistance,easy processing,high specific strength,and convenient forming.The density of aluminum alloy is about one-third of that of ordinary steel,and its strength is equivalent to the stiffness of conventional steel.Therefore,aluminum alloy structures can obtain larger spans,which is attracting more and more attention and favor from architects and structural engineers.In order to give full play to the advantages of lightweight and high strength of aluminum alloy honeycomb plates and overcome the shortcomings of low elastic modulus of aluminum alloy reticulated shells,this paper proposed a new type of aluminum alloy honeycomb plate cylindrical composite reticulated shell structure.The composite reticulated shell structure is composed of aluminum alloy honeycomb plate and aluminum alloy reticulated shell connected by locking riveting,in order to achieve the purpose that aluminum alloy honeycomb plate and aluminum alloy reticulated shell work together.In this paper,a cylindrical reticulated shell structure with a size of 4 400 mm×1 530 mm×1 100 mm was designed and prepared,and the bearing capacity test was carried out to study the stress characteristics and failure mechanism of the cylindrical composite reticulated shell.On the basis of considering the influence of double nonlinearity and instability,the nonlinear finite element analysis of cylindrical composite reticulated shell was carried out.The reliability of the finite element analysis method was verified by comparing the results of finite element analysis with the bearing capacity test.The results show that the main failure modes of the connector are that the core-pulling rivet at the short span was cut off when the composite reticulated shell plate-bar was destroyed;the side span was pulled off by the core pulling rivet due to aluminum alloy warping;there is a trend of plate dislocation around the locking rivet connector,but it is not damaged.The failure modes of the aluminum alloy member include the fracture of the aluminum alloy member along the weak part of the opening at the maximum stress in the span and side span compression buckling.Aluminum alloy honeycomb plate also occurred degumming phenomenon in the larger bar deformation.Before the displacement of the loading point is 30 mm,the specimen is in the elastic stage and then enters the elastic-plastic stage.The nonlinear behavior of the cylindrical reticulated shell is mainly determined by the locking riveting performance between the aluminum alloy rod and the honeycomb panel.The bearing capacity of the cylindrical composite reticulated shell specimen is 6 951 N,and the load continues to decrease with the increase of displacement.The finite element analysis model considering double nonlinearity can effectively simulate the mechanical performance of the composite reticulated shell in the elastoplastic stage,and the deformation and mechanical performance of the composite cylindrical reticulated shell after instability can be well simulated after considering instability.The finite element simulation method proposed in this paper can accurately simulate the load-displacement curve of cylindrical reticulated shells.The calculation efficiency is high,the convergence is good,and the error of ultimate bearing capacity is about 2%.The locking riveting connection integrates opening and forming.Only positioning can use the locking riveting connection tool to form the locking riveting.The processing efficiency is the highest,the forming quality is guaranteed,and the stability is better than the traditional mechanical connections.In the future,"assembly line" production can be formed to improve the degree of building industrialization.