FRC/钢燕尾槽单向连接结构强度特性及损伤机理

The design and mechanical characteristic research of swallow-tailed slot joint of FRC/steel

针对纤维增强复合材料(FRC)与钢结构的紧密坚固连接要求,提出并设计了FRC/钢结构燕尾槽单向嵌入式胶接连接结构形式.初步设计的连接结构试件单向面内抗剪极限强度试验测试结果显示:由于层间剪力引起的自由端效应影响,FRC/钢燕尾槽连接结构的初始损伤将最先出现在自由端部,导致连接结构紧密性连接要求不能得到满足,而槽体连接区内纤维的层间分层和拐角区树脂基体的挤压损伤以及上下层间界面剥离构成了燕尾槽单向连接结构抗剪承载时的典型损伤及破坏模式.为此,提出了自由端部增强改进结构形式.采用有限元数值方法(Abaqus/Standard)对改进前、后两种连接结构界面应力分布特性进行分析,改进结构试验研究结果表明:改进后单向燕尾槽连接结构层间界面应力分布更趋合理,自由端部分层初始损伤得到有效抑制,燕尾槽单向连接结构能在有效保证水密性要求的前提下,使抗剪极限强度提高约61%.

The swallow-tailed slot joint has been put forward and the primary configuration has been designed to meet the demands of water-tight and strong connection between steel and FRC.The tensile strength tests for primary configuration have been carried out,and the results show that,the initial damage of peel breakage appeares at the free end,owing to the convergence of peel stress.Subsequently,the delaminate between upper layers and the slot layers,the extrusion damage of resin matrix,and the shear failure between the interfaces dominate the failure processes of swallow-tailed slot connection.Then,the reinforced configuration of swallow-tailed slot joint has been brought forward,the peel stress and shear stress distribution characteristic among the interfaces have been discussed by experiments and simulations（Abaqus）.The experimental results show that the reinforced joint can resist the initial damage at the free end and the strength of connection is increased by 61%.