悬索桥缆鞍系统侧向挤压作用的接触元法与计算公式

CONTACT ELEMENT METHOD AND FORMULAS FOR CALCULATIONS OF LATERAL SQUEEZING INTERACTION BETWEEN MAIN CABLE AND SADDLE IN SUSPENSION BRIDGES

  • 摘要: 在悬索桥塔顶鞍槽内,主缆钢丝与鞍槽侧壁及钢丝间均存在相互作用力,包括挤压力与摩擦力,其准确、高效的计算对主缆抗滑设计至关重要。本文提出一种接触元分析方法,为悬索桥缆鞍系统的建模与求解提供新的方法。以离散刚体理论为基础,引入有限元方法中节点与单元的概念,构思钢丝与钢丝间、钢丝与鞍槽间的接触元,该接触元为直线型单元,具有1个压力自由度。通过几何“线”模拟接触元并在钢丝圆心汇交为节点,可方便地建立整个缆鞍系统模型,支持大量不同摩擦系数的定义,生成系统方程组进行直接求解。基于ANSYS-MATLAB联合编程对方法进行实现,通过试验数据验证对方法的正确性进行了验证,并探讨了方法中钢丝扭转平衡问题及方法在随机分析方面的应用。最后,推导了钢丝对鞍槽侧压力及其合力的计算公式。研究成果为计算悬索桥缆鞍系统的抗滑分析提供参考。

     

    Abstract: In the saddle at the top of a suspension bridge tower, steel wires and the saddle interact with each other to generate a pressure and a friction force, the efficient and accurate prediction of which is very important to the sliding resistance design of the main cable. This study proposed a new contact element method for the simulation and calculation of the interaction between the cable and the saddle. This method is based on the discrete rigid body theory, the nodal and element conceptions in the finite element method are introduced to construct the contact elements between steel wires and the contact elements between the steel wire and the saddle. The contact element can be expressed as a straight-line element with one compressive force degree of freedom. Thus, the cable-saddle system can be modeled using geometric lines connecting the centers of steel wires, supporting the definition of many different friction coefficients and generating an equation system to be solved directly. The ANSYS-MATLAB joint code is adopted to implement the algorithm. Experimental data validates the developed codes. Subsequently, the torsional unbalanced issue in the method and the stochastic analysis of the proposed contact element method are discussed. Finally, hand-calculation formulas for the side compressive force and its resultant of cable-saddle systems are derived. The present study provides an essential reference for the calculations of sliding resistance of cable-saddle systems in suspension bridges.

     

/

返回文章
返回