A numerical method to solve structural dynamic response caused by cable failure

Abstract

PurposeInstantaneous unloading with equal force is usually used to simulate the sudden failure of cables. This simulation method with equivalent force requires obtaining the magnitude and direction of the force for the failed cable in the normal state. It is difficult, however, to determine the magnitude or direction of the equivalent force when the shape of the cable is complex (space curve). This model of equivalent force may be difficult to establish. Thus, a numerical simulation method, the instantaneous temperature rise method, was proposed to address the dynamic response caused by failures of the cables with complex structural form.Design/methodology/approachThis method can instantly reduce the cable force to zero through the instantaneous temperature rise process of the cable. Combined with theoretical formula and finite element model, the numerical calculation principle and two key parameters (temperature rise value and temperature rise time) of this method were detailed. The validity of this approach was verified by comparing it with equivalent force models. Two cable-net case with saddle curved surfaces were presented. Their static failure behaviors were compared with the dynamic failure behaviors calculated by this method.FindingsThis simulation method can effectively address the structural dynamic response caused by cable failure and may be applied to all cable structures.Originality/valueAn instantaneous temperature rise method (ITRM) is proposed and verified. Its calculation theory is detailed. Two key parameters, temperature rise value and temperature rise time, of this method are discussed and the corresponding reference values are recommended.

Aeolian Vibration Dynamic Analysis of Large-Span, Relaxed Antenna Cable Net Based on Finite Particle Method

“…When a 'locking effect' occurs, cos φ = 1 and P w = πF y f A 0 . Both F y and A 0 are functions of the space coordinate x along the wire, P w = πF y (x) f y(x), then we derive the formula of alternating upward force F y in Equation (10).…”

“…sin ωt (10) According to the expression of wind energy power proposed by Diana and Falco [12], the above, Equation (10), is substituted into Equation ( 8) to obtain the aeolian excitation force in Equation (11).…”

“…On the other hand, although the finite element method has been widely used in general cable structure engineering to establish structural models and estimate the dynamic characteristics of large-span cable structures, due to the low pre-tensioning level of large-span antenna networks, the cable structure may experience relaxation in a specific section under a wind load. In this case, the stiffness matrix of the corresponding relaxed part of the cable elements in the FEM calculation is singular and cannot be solved [9,10]. In addition, when analyzing problems involving large rotations, large deformations, or mechanism movements and non-continuum deformations, the implicit finite element method will encounter fundamental difficulties due to theoretical limitations [11].…”