Lightweight design of turnover frame of bridge detection vehicle using topology and thickness optimization

Turnover frame is one of the core connection parts of the bridge detection vehicle. Its performances, including stiffness, manufacturability and durability, are essential for the bridge detection vehicle. Lightweight of turnover frame can decrease the total vehicle weight, which is well conformed to the Chinese national standard GB 1589-2016 (Limits of dimensions, axle load and masses for motor vehicles, trailers and combination vehicles). In this paper, the methods of topology and thickness optimization are utilized to design a new turnover frame. Firstly, the finite element (FE) models of original turnover frame and up mechanism are created, and then the von Mises stress and deformation are obtained. The FE results are validated by the stress experiment of the turnover frame, the maximum error is 7.8% relative to experiment results. Secondly, a novel layout of turnover frame is obtained using solid isotropic microstructure with penalization (SIMP) method under multi-conditions. The thickness optimization is carried out based on topology optimization results. The manufacturability and functionality are considered for optimized results. Finally, stress and durability experiment validations of optimal design are carried out. The stress results are consistent with the simulation, and the structure is in excellent conditions after 600,000cycles of repeated loads under harsh working conditions in proving ground. By comparing the FE results between the original and optimal turnover frame, it shows that the optimal scheme has 21.5% reduction in total mass while maintaining better stiffness and durability.