The Theoretical Analysis And Program Development Of The Frictional Slip Cable Element

The cable structure has the advantages of light mass,high efficiency,large span,and economy.It plays a vital role in the light and high-efficiency structures such as chord-supported domes,the tension string truss,and the tensioning system.Regardless of whether the structure is in the process of tension forming or using,,due to the unbalanced force,the sliding cable will slide at some nodes.At present,the influence of friction is mostly neglected when considering cable slip.Moreover,most commercial finite element software such as ANSYS,ABAQUS and SAP2000 are not good at simulating the friction slip process of the cable.In order to make the sliding cable element accurately reflect the deformation and the internal force of the cable body after the cable is combined with the whole structure,this article has done the following work:Based on the principle of virtual work,the internal force vector and stiffness matrix of a three-node sliding cable element are derived.Based on the Coulomb friction theory,it is judged whether the cable body slides and the internal force relation between tight edge and loose edge.Take the strain on the tight edge and loose edge to establish a three-node sliding cable element,a node with the same state of the three-node sliding cable element with tribological considerations is captured with a rigid arm,and compile a set of set process diagrams.and the element is integrated into a three-node continuous fold-ing clue element that considering friction in the set of intermediate nodes.Using FORTRAN language to compile the finite element calculation program of the three-node sliding cable element that considering friction.And then the element is written to the ANSYS element library through the UPFS finite-element programmed development function.The feasibility of this method is verified by the examples.Comparing the calculation results with other literatures shows that the method has high calculation accuracy and wide application range.At the same time,complicated iterative procedures are not needed to solve the friction slip problem,and the calculation speed is fast.Moreover,the sliding cable element considering friction,which is written in this paper,can be connected and cooperated with other beam element in the finite element software.