基于DICM的钢管混凝土框架梁柱连接的转角测量与分析研究

EXPERIMENTAL STUDY ON MEASUREMENT OF INTERSECTION ANGLES OF FRAME CONNECTIONS BETWEEN COLUMN AND BEAM OF CONCRETE-FILLED STEEL TUBE USING DICM

由于钢管混凝土框架梁柱连接形式的多样性和受力形式的复杂性,目前还未能建立实用、有效的连接区工作性能的评判标准。连接的转角是其研究的重要指标,因此连接转角测试方法的实用性和有效性对连接工作性能研究的深入开展有非常重要的影响。数字图像相关方法(DICM)具有非接触、无附加质量、精度高和全场测量的优点,但局限于有限变形和小转角测试。基于以上两点,结合钢管混凝土框架钢加强环式梁柱连接的模型实验,利用改进的数字图像相关方法,对该连接的弯矩-转角关系进行了测试。根据梁柱及其连接的变形特点,采用基于全局坐标的形函数,测得了管壁处、加强环边及一倍梁高处截面的弯矩-转角关系,该方法适用于精确测试发生较大刚体转动及形变的试件。通过该模型实验,验证了该方法用于测试钢加强环式连接转角的可行性,并为进一步分析钢加强环式连接的工作性能提供了实验依据。

The primary objective of this study is to demonstrate the feasibility of measuring intersection angle of the steel stiffening ring connection using the digital image correlation method （DICM）. Due to the availability of a number of methods to connect the concrete-filled steel tube column with beam and their complex load/force transferring mechanisms, effective methods to measure the intersection angles of the connections have not been developed. DICM offers the advantages of a non-contact, high-precision, whole field system and does not add weight but is limited by its measuring range excluding large rotation and deformation. According to the features of the beam, column and their connection, shape functions in global co-ordinates are generated and used. From the modal experiment of the steel stiffening ring connection for concrete-filled steel tube column and beam frames, an improved DICM is used to investigate the relation between bending moment and intersection angle of the connections. The final results include the relationship between the bending moment and the rotational angle for different sections of the tube as connected to the column. Those include the joint points between the column and the stiffening ring, the stiffening ring and section of the beam and the section away from the stiffening ring on the beam （the distance equals to the height of the beam）. By virtue of the analysis of the modal experiment, DICM is proved to solve the problem and find the exact intersection angle in the connections.