Prestressed Cable-Spring Joints as a Lightweight Reinforcement Strategy for Tubular Body Structures in Conventional and Autonomous Buses

Bus body structures are commonly reinforced by increasing the dimensions or number of steel members, resulting in higher vehicle mass and material consumption. This study proposes a lightweight reinforcement concept based on prestressed Cable Spring (CS) joints for tubular bus body structures. An analytical model describing the stiffness contribution of tension-only prestressed cables was developed and implemented in Ansys Mechanical. The concept was evaluated using finite-element models of the low-entry city bus body “4289” under two representative loading conditions: diagonal racking and inertial loading prescribed by UNECE Regulation No. 100 (R100). Under diagonal racking, the proposed CS system reduced the maximum von Mises stress by 2.7%, the average stress by 16.2%, and the maximum total deformation by 28.4%. Under the R100 transverse 5 g loading condition, the combined catenary-curved and CS configuration decreased the maximum equivalent stress, average stress, and maximum deformation by 41.2%, 24.7%, and 75.1%, respectively, relative to the conventional rectangular body frame. The results demonstrate that prestressed CS joints constitute an effective lightweight reinforcement strategy for improving the structural efficiency of tubular body structures of conventional and autonomous buses, with these benefits being primarily associated with reduced structural material use.