基于不等宽摩擦型叠梁模型的平行钢丝索层间滑移有限元分析  

Finite Element Analysis of Interlayer Slip in Parallel Wire Cables Based on Unequal Width Frictional Laminated Beam Model

作　　者：李志鹏 张卓杰 甄晓霞[1] 赵勇霖 LI Zhipeng;ZHANG Zhuojie;ZHEN Xiaoxia;ZHAO Yongin(School of Civil Engineering and Transportation,South China University of Technology,Guangzhou 510006,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)

机构地区：[1]华南理工大学土木与交通学院,广州510006 [2]石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室,石家庄050043

出　　处：《铁道标准设计》2024年第9期104-112,共9页Railway Standard Design

基　　金：国家自然科学基金项目(52178138,51908382);广东省自然科学基金项目(2021A1515012064)。

摘　　要：斜拉桥结构中,斜拉索锚固端往往存在强制转角,索内钢丝可能因此产生分层滑移,导致截面整体性被破坏、抗弯刚度退化。为探究平行钢丝索锚固端的分层滑移现象,基于不等宽摩擦型叠梁模型,通过引入非线性弹簧单元,提出一种模拟钢丝分层滑移的算法。依据该算法建立一个11层叠梁模型,对其在跨中集中力作用下的滑移扩展和变形规律进行进一步研究。结果表明:随着外荷载增加,叠梁接触层沿梁高方向从中性轴位置向两侧逐层产生滑移,沿梁长方向从固定端和跨中集中力作用点向两侧对称扩展;与此同时,该叠梁的全截面抗弯惯性矩呈指数衰减,最终约为初始状态的1/100,整体刚度也随滑移开展而加速衰减;受滑移效应影响,叠梁整体挠度呈非线性加速增长,但在低荷载水平时,叠梁锚固端附近位置接触层会全部滑移,从而导致该区域挠度按照线性规律增加,且增长幅度最大;此外,叠梁轴力会影响接触层的剪力传递效率,轴力越大,剪力传递效率越低,沿梁高方向产生滑移的接触层越少,沿梁长方向接触层滑移扩展速度越慢。In cable-stayed bridge structures,the anchorage ends of stay cables often experience forced rotation,which can cause interlayer slip among wires within the cables,leading to the destruction of the cross-sectional integrity and a reduction in bending stiffness.To study the interlayer slip phenomenon at the anchorage ends of parallel wire cables,an algorithm for simulating the slip effect of steel wires was proposed based on a frictional laminated beam model with unequal widths by introducing nonlinear spring elements.In this paper,an 11-layer laminated beam model was established to further study slip propagation and deformation patterns under concentrated load at mid-span.The results showed that as the external load increased,slip between the contact layers of the laminated beam occurred gradually from the neutral axis towards both sides in the vertical direction and symmetrically extended from the fixed end and mid-span load points towards both ends along the beam length.Meanwhile,the full-section bending moment of inertia of the laminated beam decayed exponentially,ultimately reaching approximately 1/100 of its initial state,and the overall stiffness decreased rapidly as slip progressed.Affected by the slip effect,the overall deflection of the laminated beam exhibited nonlinear accelerated growth.However,at low load levels,the contact layer near the anchorage end fully slipped,resulting in a linear increase in deflection in this region,with the largest growth amplitude.Additionally,the axial force influenced the shear transfer efficiency of the contact layers-the greater the axial force,the lower the shear transfer efficiency,the fewer contact layers slipped in the vertical direction,and the slower the slip propagation speed along the beam length.

关 键 词：斜拉桥 平行钢丝索 非线性弹簧单元 不等宽摩擦型叠梁 层间滑移效应 

分 类 号：U24[交通运输工程—道路与铁道工程] U448.27[建筑科学—桥梁与隧道工程]