Optimization Design and Mechanical Properties of the Disc in Disc-Buckled Steel Tube Scaffolding

As a key component of load transfer in the joint components of the disc-buckled steel tube scaffold， the disc plays a decisive role in the overall stability. However， when multiple bending crossbars are connected simultaneously， stress concentration occurs in the disc， leading to a reduction in the joint stiffness value.To improve the stiffness value and flexural capacity of the disc， this paper explored material distribution in the disc that can maintain the stiffness value through topology optimization， followed by an optimized design of the disc. A trilinear model and a cubic B-spline mathematical fitting method were applied for numerical fitting， the feasibility of the optimization scheme was verified， and the bending moment values for the scaffold joints entering the elastic-plastic stage under different numbers of crossbar connections were proposed. The results showed that the moment of inertia of the contact section between the disc and the lock had a significant influence on the joint stiffness value. The optimized design of Disc 1 increased the stiffness value by 2%-3%， 19%-23%， and 13%-19% in the three stages of the trilinear model， respectively， and raised the bending moment value by 7.5%. The optimized design of Disc 2 increased the stiffness value by 4%-6%， 29%-37%， and 20%-26% in the three stages of the trilinear model， respectively， with a notable enhancement in the ultimate bearing capacity. As the number of crossbars increased， the bending moment at which the joints entered the elastic-plastic stage decreased. Specifically， the values were 0.6 kN·m， 0.5 kN·m， and 0.4 kN·m for the joints connected with one， two （right-angled）， and four crossbars， respectively. Therefore， it is recommended to avoid joints with multiple connected crossbars in scaffold construction.