动态缆铠装层断丝效应研究

Research on Fracture Effect of Dynamic Cable Armour

铠装钢丝作为动态缆中提供结构保护的单元,易遭受局部载荷,产生局部破坏。对此,探究铠装层局部断裂对动态缆的影响,以评估动态缆在局部铠装钢丝断裂之后的可靠性。确定铠装钢丝断口在缆轴向的影响范围,以评估动态缆本体受影响的范围;确定铠装钢丝断口在缆周向的应力集中效应,以评估断丝周围铠装钢丝由于断丝的应力集中效应,进一步发生断裂的可能性。采用一种截面型式的动态缆,设置不同断丝数的铠装层断口,对断口在轴向的影响范围和周向的应力集中情况进行分析,以便通过试验探究断丝的影响效应。同时,结合钢绞线断丝影响的探究结果,对动态缆铠装层存在一根断丝时的恢复长度进行理论分析,得到断丝恢复长度为1.07倍节距长度。试验结果表明,在轴向上,钢丝断口的恢复长度在1~2个节距范围内;在周向上,每断1根钢丝,在周围钢丝上的应力放大系数不超过1.14。

Being the units that provide structural protection in dynamic cable,armour wires are easy to suffer local loads and thus be locally broken.In this regard,to assess the reliability of dynamic cable with local broken armour wires,the influence of broken wires need to be determined.To be more detailed,axial influence range of broken wires’fracture points is determined to evaluate the influence range of dynamic cable armour itself,while hoop stress concentration effect of broken wires’fracture points is determined to assess the possibility of further failure.To research the influence of broken wires,a cross-section type dynamic cable type is adopted and fractures with different numbers of broken wires are set up to analyze the axial influence range of fracture points and hoop stress concentration effect.Meanwhile,combined with some conclusions of steel wire rope local fracture influence,theoretical analysis of recovery length of dynamic cable armour with 1 broken wire is carried out,and the result is 1.07 times the length of pitch length.The experiment results show that the recovery length is between 1 pitch and 2 pitches of armour wire and the stress amplification coefficient of adjacent wires does not exceed 1.14 per broken wire in circumferential direction.