Amplification mechanism of double rhombic struts in adaptive beam string structures

The inadequate control accuracy and sensitivity of active struts in adaptive beam string structures (ABSS) significantly limit their adaptability to various external loads. In response to this challenge, a novel adaptive beam string structure with double rhombic struts (DRABSS) was proposed. The upper and lower rhombic active struts were designed to improve control accuracy and sensitivity, respectively. A geometric displacement and force model of the double rhombic strut was established to analyze the influence of the initial angle on its control function. A design formula for the double rhombic strut was derived and verified for accuracy. Furthermore, considering the structural response as the optimization objective, research on a specific model of DRABSS under active control was conducted using genetic algorithms (GA). The results indicate that optimizing the structural displacement is more effective in achieving the desired control values than optimizing stress. When displacement is selected as the control objective, the control effectiveness of displacement under full-span load is optimal. When stress is considered the control objective, the control effectiveness of stress under symmetric loads is better than that under asymmetric loads. Multi-objective optimization control is an effective method for reducing the risk of optimization results falling into local optima compared to single-objective optimization control, and the higher control requirements for both displacement and stress can be achieved simultaneously.