| A high-sensitive mass sensing mechanism is crucial for improving the performance of resonant mass sensors.As a sensitive core element of resonant mass sensors,coupled resonant beam structures are widely used for micro-mass sensing,environmental monitoring,detecting and early warning of trace substances such as toxic and harmful gas molecules.However,traditional resonant sensors are difficult to break through the bottleneck of high sensitivity and mass sensing due to the limitations of processing technology,structural dimensions and working environment.Therefore,proposing a new sensing mechanism has great engineering value and significance for improving the sensitivity performance of resonant mass sensors.Mode localization,as a change in modal characteristics caused by energy localization in weakly coupled systems under detuning perturbation,has received widespread attention and has been widely used in fields such as highly sensitive detection and energy harvesting in recent years.In this paper,the localization characteristics of weakly coupled resonant beam structures in linear,weakly nonlinear,and strongly nonlinear modes and their highly sensitive mass sensing mechanisms have been studied to improve quality detection performance.The specific research work carried out is as follows:The mass sensing mechanism of a coupled resonant beam based on mode localization has been studied.A general dynamic parameter model of coupled resonant beam structure has been established,and the output response characteristics of the coupled system under both single beam driving mode and in-phase overall driving mode have been respectively analyzed,and the in-phase overall driving scheme has been established;The parametric models of symmetric and asymmetric coupled resonant beams have been established.Based on the first order perturbation method,the expressions of eigenvalues and eigenvectors of the detuned system under the two coupling models have been solved.A comparative analysis between simulation and experimental methods has been conducted to verify the high localization characteristics and mass sensitivity of the proposed asymmetric gradient coupled resonant beam;Through theoretical analysis,the coupling structure of the system has been optimized and the optimal gradient angle has been established;The introduction of Duffing nonlinearity into the system by means of magnetic perturbation.The amplitude frequency response of the system under mass perturbation has been numerically analyzed.Experiments have demonstrated that the introduction of Duffing nonlinearity is beneficial to the realization of highly sensitive mass sensing in a coupled resonant beam.A highly sensitive linearized output method based on a coupled resonant beam has been studied.A highly sensitive linearization output method based on amplitude difference has been proposed to solve the problem of low output linearity caused by the introduction of Duffing nonlinearity.A dynamic parameter model of a five-degree-of-freedom coupled resonant beam has been established,and the theoretical expression between its amplitude difference and perturbation has been derived,the linearization characteristics of the output method has been revealed;The sensitivity characteristics of the amplitude difference output scheme and the amplitude output scheme have been analyzed and compared.The simulation analysis results show that the amplitude difference output scheme for weakly coupled resonant systems can maintain high linearity and sensitivity in nonlinear perturbed environments,and has a high suppression effect on non-ideal interference in the environment.The energy transfer characteristics of a nonlinear weakly coupled resonant system under mass perturbation detuning have been studied.By increasing the overall driving force amplitude of the coupled resonant beam system,the weak nonlinear vibration mode of the system was realized;A dynamic parameter model of a three-degree-of-freedom weakly coupled Duffing system has been established.The influence of mass perturbation on the amplitude frequency characteristics of the coupled system has been analyzed through theoretical and numerical methods,revealing the feasibility of the sensing mechanism;The localization characteristics of the coupled system in the both linear mode range and the weakly nonlinear mode range have been analyzed and compared by experiments,further verifying the high mass sensing sensitivity of the nonlinear coupled system;A mass sensing and warning mechanism has been constructed according to the law of the influence of mass perturbation on the amplitude jump point of the coupled system.The mass sensing mechanism of a coupled resonant beam based on nonlinear mode localization has been studied.A dynamic parameter model of a three-degree-of-freedom weakly coupled Duffing system has been established.The periodic solution of the system has been derived by using the harmonic balance method.The stability of the periodic solution has been analyzed by using the Floquet theory,and the multi-stability of the coupled system has been established;Combined with numerical analysis,the frequency-energy response curves of the coupled system have been constructed,and the localization characteristics and mass perturbation characteristics of different bifurcated modes have been analyzed;An experimental testing system was built to analyze the multi-stable physical phenomena of the coupled resonant beam system and verify the localization and isolation characteristics of the system’s bifurcated modes.The feasibility of nonlinear mode localization and highly sensitive mass sensing have been further verified through mass perturbation. |
