泥石流冲击作用下CFRP加强型柔性索网体系动力响应分析

Dynamic response analysis of CFRP strengthened debris flow flexible cable net system

为了使泥石流柔性防护索网体系具有更好的耐久性和抗冲击性,将轻质高强、耐腐蚀性较好的碳纤维复合材料(CFRP)与索网结合,提出一种加强型柔性索网体系.通过九组静力拉伸试验、并运用有限元软件ANSYS/LS-DYNA进行数值模拟,研究CFRP材料对筋材静力性能的影响,研究冲击荷载作用下单索、组合索以及索网在粘贴碳纤维布后的动力响应,探讨碳纤维布对柔性索网抗冲击性能的影响,并与无碳纤维布的情况进行对比分析.结果表明:在拉伸试验中,碳纤维布对于筋材的屈服强度有明显的提升作用,但对拉伸强度的提升不明显;在模拟的冲击过程中,粘贴碳纤维布的钢索整体刚度有一定的提升,同时在各级冲击荷载作用下的位移有所减小;碳纤维布在不发生失效的情况下能分担一部分钢索应力;冲击点附近以及钢索固定端处的碳纤维布容易发生失效破坏,致使钢索应力产生“突变”现象.

In order to improve the durability and impact resistance of debris flow flexible cable net system,a reinforced flexible cable net system combining lightweight,high strength and corrosion resistant carbon fiber reinforced polymer(CFRP)with cable net is proposed.Through nine groups of static tensile tests and numerical simulation with finite element software ANSYS/LS-DYNA,the influence of CFRP material on the static performance of reinforcements is analyzed.The dynamic responses of single cable,composite cable and cable net pasted with carbon fiber cloth under impact loading are also studied.The effect of carbon fiber cloth on impact resistance of the flexible cable net is discussed and compared with that of flexible cable without pasting carbon fiber cloth.Tested results show that in the tensile test,carbon fiber cloth can obviously improve the yield strength of reinforcement,but the improvement of tensile strength is not obvious.In the simulated impact process,the overall stiffness of the steel cable bonded with carbon fiber cloth may be improved to a certain extent,and the displacement is reduced under all levels of impact loads.Carbon fiber sheet can share part of stress of a steel cable without failure.The carbon fiber sheet near the impact point or at the fixed end of the cable is prone to failure,resulting in a“sudden change”in the stress of the cable.