高强钢板组合螺栓抗拉性能有限元分析

Finite element analysis on tensile performance of high-strength steel plate composite bolt

摘要:

高强钢板钻孔攻丝后替代螺母,与高强螺杆组合成一种新的单边螺栓连接副,可用于钢管柱框架节点.为研究钢板组合螺栓抗拉承载力和破坏机理,在本组试验研究的基础上对4类钢板组合螺栓共64个试件进行单调拉伸数值模拟,以板厚和螺杆直径为研究变量,包括Q345B、45号钢、Q460C和Q690D四种钢材和10.9级M16、M20、M24、M27和M30五种规格高强螺栓.结果表明:Q345B、Q460C和Q690D均可作为45号钢的替代材料；钢板组合螺栓在锚固可靠的条件下,可按螺杆螺纹极限抗拉荷载的70%作为其抗拉设计值；钢板较薄时,发生钢板螺纹滑牙破坏,螺栓拔出,螺杆最大应力位于锚固区,钢板向外凸起,凸起量大于支点间距的1/200；钢板较厚时,发生螺杆拉断破坏,螺杆最大应力位于构造区,两种破坏模式中钢板的最大应力均位于钢板螺纹第一扣处.为保证钢板组合螺栓不发生钢板螺纹滑牙破坏,建议Q345B钢板厚度不宜低于1.15d；Q460C钢板厚度不宜低于1.10d；Q690D钢板厚度不宜低于0.95d,根据弹性力学和螺纹传力机理推导高强钢板组合螺栓抗拉承载力公式,公式计算结果与有限元结果吻合良好,研究成果可为钢板组合螺栓的设计提供参考.

Abstract:

Drilled and tapped high-strength steel plates are possible replacements of nuts and can be combined with high-strength bolts to form new assemblies that are used as blind bolts for steel tube column frame joints. In order to study the tensile capacity and failure mechanism of steel plate composite bolts, on the basis of our experimental research results, 64 specimens were tested under monotonic tensile load by ABAQUS software. The thicknesses of four types of steel plates (i.e., Q345B, 45#, Q460C, and Q690D) and the diameters of five specifications of high-strength bolts (i.e., M16, M20, M24, M27, and M30) in grade 10.9 were investigated. Results show that the Q345B, Q460C, and Q690D steel plates can replace the 45# steel plate. The tensile value of the steel plate composite bolts can be designed as 70% of the ultimate tensile load of the screw thread under reliable anchored. For thin steel plates, the bolt was pulled out, the steel plate thread experienced shear failure, the out-of-plane deformation of the steel plate was larger than 1/200 of the support distance, and the screw maximum stress located in the anchoring area. For thick steel plates, the bolt experienced tensile fracture, and the screw maximum stress located in the structural area. The positions of the maximum stress of the steel plates in the two failure modes were both at the first thread. In order to avoid the steel plate thread failure in the steel plate composite bolt, it is suggested that the thicknesses of Q345B, Q460C, and Q690D steel plates should be no less than 1.15d, 1.10d, and 0.95d, respectively. Based on the elastic mechanics and thread-related research, the formula for tensile capacity of high-strength steel plate composite bolts was derived. The calculated results were in good agreement with the finite element results. The research results can provide a reference for the design of high-strength steel plate composite bolts.