双层六边-三边形榫卯互承木结构受力性能研究

Study on mechanical properties of double-layer hex-tri timber reciprocal frame of mortise-tenon connections

互承结构构件和节点形式简单统一,通过组装小尺寸构件即可实现大跨度结构。而木材易于加工,适用于互承结构。为此,提出一种格构式木构件,通过简单的榫卯连接,可组装为双层六边-三边形榫卯互承木结构。分别搭建了单、双层六边-三边形互承木结构试验模型,相比于单层榫卯互承木结构,双层榫卯互承木结构的强度、刚度有显著提升。采用通用有限元软件ABAQUS建立了双层六边-三边形榫卯互承木结构数值模型,并通过足尺试验验证了有限元模型的正确性;在竖向荷载作用下,格构式木构件中的最大弯曲应力出现在卯眼处弦杆与腹杆的连接位置,腹杆的设置很大程度上减小了卯眼与榫头位置的应力集中现象。根据六边-三边形互承网格的几何拓展规律,考察了单、双层六边-三边形榫卯互承木结构的拓展性,提出的双层六边-三边形榫卯互承木结构可通过二次拓展达到最大跨度,可应用于较大跨度的屋盖结构。

The form of members and connections of reciprocal frame is simple and unified,and large-span structure can be realized by assembling small-sized members.Timber is suited for reciprocal frame,because it is easy to be machined.A kind of lattice-type timber member of reciprocal frame was proposed,and it can be assembled into double-layer hex-tri reciprocal frames of mortise-tenon connections.The test models of single-layer and double-layer hex-tri timber reciprocal frame of mortise-tenon connections were built respectively,and the strength and stiffness of double-layer hex-tri timber reciprocal frame are significantly improved.The finite element model of double-layer hex-tri timber reciprocal frame of mortise-tenon connections was established by ABAQUS,and the correctness of the finite element model was verified by full-scale test.Under vertical load,the maximum bending stress in the lattice-type members appears at the connection position of chord and web members in the mortise hole.The stress concentration phenomenon at the mortise-tenon connections has been greatly reduced by setting web member.According to the geometric expansion law of hex-tri gridding of reciprocal frame,the extension of single-layer and double-layer hex-tri timber reciprocal frame of mortise-tenon was studied.The proposed double-layer hex-tri reciprocal frame of mortise-tenon connections can reach the maximum span by twice extension,and can be used for large-span roof structure.