Research on Deformation Control Technology in the Fabrication of Suspended Monorail Track Beams

As a load-bearing component， the lower flange plate and web plate serve as supporting structures for the vehicle’s running wheels and guide wheels. Since the track beam is a slender hollow channel structure with low rigidity and high requirements for production accuracy， deformation control is critical to the successful fabrication of track beams. Based on the first phase of the Optics Valley Tourism Line project， a systematic study was conducted on the factors affecting deformation during the suspended monorail track beam production process. In addition to determining appropriate welding parameters through welding test evaluations， welding methods that generate high heat input should be avoided during the welding design phase to minimize welding deformation. For key units where deformation must be strictly controlled， three production schemes were applied to the lower cover plate： separate cutting of the left and right panels， full-size cutting of the lower cover plate， and overall cutting with reserved cutting points. The deformation， assembly workload， and correction work of each process were measured to determine the optimal production process for the lower cover plate unit. Two welding schemes， namely tire frame welding and full-position welding within the tire frame， were developed and tested during the assembly and welding of track beam segments. The outer contour， box opening dimensions， linear accuracy， and rework workload were measured after removal from the tire frame to determine the optimal assembly and welding scheme. Additionally， based on research and analysis of thermal correction techniques applied to trial-produced components， the appropriate correction methods and positions for the track beam structure were identified. Practice has shown that welding materials， parameters， and methods determined through welding process experiments can reduce welding deformation. For the lower cover plate unit， the "overall cutting with reserved cutting points" scheme demonstrated effective control over both cutting and welding deformation. The full-position welding scheme also proved effective in reducing welding deformation and minimizing correction work after removal from the tire frame. Based on correction studies of trial components， applicable thermal correction procedures and three specific thermal correction positions for the track beam structure were proposed.