High-resolution monitoring of aerospace structure using the bifurcation of a bistable nonlinear circuit with tunable potential-well depth

Abstract Monitoring structural parameter and strain of a flight vehicle is important for safety inspection. To detect the nuanced variation of the structural parameter and strain, this study proposes a novel bistable nonlinear circuit with tunable potential-well depth (TPWD), and integrates it with electromechanical transducer (e.g. piezoelectric transducer and strain gauge) to form a high-resolution structural sensor. The TPWD bistable circuit's bifurcation feature can significantly magnify the response's difference before and after the variation of the structural parameter and strain. It is beneficial to detection of the tiny structural variation. The theory of the TPWD bistable circuit and its application in high-resolution structural monitoring are presented. Then, experimental studies of the TPWD bistable circuit and its performance coupled with a structure are performed, which quantitatively and qualitatively verifies the theoretical predictions and the circuit's feasibility for structural detection. It is seen that the circuit's potential-well depth can be tuned to manipulate the bifurcation point, which can be adapted to different excitation levels. Finally, this paper performs investigations of the TPWD bistable circuit for detecting the variation of a wing structure's parameter and strain, respectively. Results show that by means of the TPWD bistable circuit's bifurcation, nuanced variations of both the structural parameter and strain can be evidently detected, leading to high-resolution structural monitoring.