缆索热铸锚具的精细化建模和有限元分析

High Precision Modeling and Finite Element Analysis for Hot-Cast Anchor Sockets for Cable Structures

编写了适于参数化分析的热铸锚具的数值仿真命令流,锚具的精细有限元数值模型中分别采用三维两节点梁单元Beam188来模拟钢丝,三维八节点实体单元Solid185来模拟锚杯和铸体;通过设置多点约束中的刚臂单元MPC184来模拟钢索的截面影响,通过刚臂与实体单元节点之间的点点接触单元Conta178模拟钢丝与热铸锚铸体之间的接触和摩擦;通过面面接触单元Conta173来模拟锚杯内侧面与铸体浇注面之间的连接.在此基础上研究了钢丝束直径和股数对锚具受力的影响,并进行了比较分析;对锚具进行了设计荷载和破断荷载下的静力分析,给出了锚具的应力和变形分布.最后,考虑到施工工艺误差和安装偏差等因素,锚具节点在实际受力时经常承受局部弯矩,研究了在轴向力和侧向水平力共同作用下的热铸锚具的应力变化.本文研究结果表明:热铸锚具内部应力分布不均匀,应力集中主要出现在锚杯与铸体连接处和锚杯杯口位置,其他部位的应力相对较小;在侧向荷载作用下,应力分布发生了较显著变化,最大应力点的位置也发生了侧向偏移.

In this paper the authors present the program which is useful to parametric modeling and analysis of the hot-cast anchor sockets. In ANSYS the 3D two-node beam element Beam188 was used to simulate the steel wire strand of cable, and 3-D 8-node structural solid element Solid185 to simulate the anchor cup and casting solid. Considering the section area influence of steel wire strand, rigid beam of multipoint constraint element MPC184 were used. The 3-D node-to-node contact element Conta178 between the rigid beam node and the solid element＇s node to simulate the contact relationship between the steel wire strand and hot-cast anchor casting solid, and 3-D 4-node surface-to-surface contact element Conta173 were used to simulate the connection between inner surface of anchor cup and casting surface. Combining all the above elements the complexed high-precision finite element simulation model for hot-cast anchor socket were presented. On the base of the model presented in this paper the stress distribution by changing the wire strand number and section area in anchor cable were studied and compared. And then the static stress analysis and displacement distribution analysis were done separately in the design load condition and the limit load condition. At last considering the possibility of construction and building error and accordingly introducing the local moment in anchor socket, the stress distribution and difference for hot-cast anchor sockets with the proportional transverse force according to the axial force were also studied. The results in this paper show that the stress distribution and hot stress position of the hot-cast anchor sockets for cable is obviously inhomogeneous; the hot-stress points often occur in the connecting position between the anchor socket cup and the casting material, and also occur in the mouth position of the anchor socket cup; and the stress in other parts is relatively small. Under transverse load, the stress distribution has changed obviously, and the location of the hot stress point position is obviously and partially changed.