外伸端板连接端板加劲肋设计及有限元研究

目的 为解决工程中使用的端板加劲肋设计不合理的问题．方法 从两方面推导和归纳了端板外伸加劲肋的强度设计公式：避免梁翼缘、加劲肋和端板之间应力传递不均；保证梁翼缘内外侧螺栓拉力的均衡．并考虑了三角形加劲肋较矩形板的折减．应用有限元软件ANSYS研究了节点弯矩转角曲线、螺栓拉力变化及梁翼缘内外侧螺栓拉力分配系数．结果 研究表明：工程中常用的端板加劲肋强度和刚度均较低，会过早屈服和屈曲；应用笔者设计的端板加劲肋能够有效提高节点抗弯力臂，延缓梁受压翼缘屈曲，将梁内塑性铰转移到加劲肋尾部．结论 ANSYS计算结果表明。端板加劲肋设计公式设计出的加劲肋较工程中常用的加劲肋能起到更好地加劲作用；并且该设计公式简单实用．

Design Approach of Stiffeners in Extended End Plate Connections and Finite Element Analysis

End plate stiffener failures occur in a number of tests in recent years,which shows an inadequacy of the knowledge about the role of stiffeners in this type of connections.No relevant rule is given in design codes for steel structures.A strength requirement for the stiffeners from two aspects is proposed to avoid the abrupt stress transmission from the beam flanges to stiffeners and from the stiffeners to the end plate and to assure uniformity of forces in bolts inside and outside of the flanges.The effectiveness of a triangular stiffener relative to a long rectangular plate in transmitting stresses is taken into account.A balance between the force transmitted by the stiffener and that by the beam flange is considered.FE analysis using contact element in ANSYS is carried out to compare the behavior of connections without stiffeners and those with stiffeners of different configurations and thicknesses.It is found that:(1)the common stiffeners often yield or/and buckle prematurely;(2)stiffeners designed in this study can reduce the end plate deformation,increase arm length of the connection against the bending moment,assure uniformity in bolt forces,and postpone the buckling of the compressed flange efficiently.