Importance Evaluation for Components in Spatial Cable-Truss Structures Based on Improved Strain Energy Method

Based on the reduction rate of the total strain energy of the structure after the members are removed and the standard deviation of the change rate of the member’s strain energy, this paper proposes an ISE (Improved Strain Energy）method to evaluate the importance of the members of the spatial cable-truss structure. The method begins by solving the internal force and displacement time-history response during member failure, calculating each member’s strain energy change rate, and obtaining the total strain energy reduction rate and the standard deviation. The analysis shows that in annular crossed cable-truss structures, the upper chord cable is the most critical, followed by the lower chord cable and strut, with failure causing only minor localized effects. In spoke-type structures, the ring cable is most critical when it contains a single cable, but its importance decreases as more cables are added, reducing the risk of collapse.