The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Eul...The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Euler-Bernoulli model with inextensible deformation. A nonlinear distributed parameter model of cantilevered piezoelectric energy harvesters is proposed using the generalized Hamilton＇s principle. The proposed model includes geometric and inertia nonlinearity, but neglects the material nonlinearity. Using the Galerkin decomposition method and harmonic balance method, analytical expressions of the frequency-response curves are presented when the first bending mode of the beam plays a dominant role. Using these expressions, we investigate the effects of the damping, load resistance, electromechanical coupling, and excitation amplitude on the frequency-response curves. We also study the difference between the nonlinear lumped-parameter and distributed- parameter model for predicting the performance of the energy harvesting system. Only in the case of parametric excitation, we demonstrate that the energy harvesting system has an initiation excitation threshold below which no energy can be harvested. We also illustrate that the damping and load resistance affect the initiation excitation threshold.展开更多
Based on the Biot’s wave equation and theory of thermodynamic, Darcy law of fluid and the modified Fourier law of heat conduction, a nonlinear fully coupled thermo-hydro-elastodynamic response model (THMD) for satura...Based on the Biot’s wave equation and theory of thermodynamic, Darcy law of fluid and the modified Fourier law of heat conduction, a nonlinear fully coupled thermo-hydro-elastodynamic response model (THMD) for saturated porous medium is derived. The compressibility of the medium, the influence of fluid flux on the heat flux, and the influence of change of temperature on the fluid flux are considered in this model. With some simplification, the coupled nonlinear thermo-hydro-elastodynamic response model can be reduced to the thermo-elastodynamic (TMD) model based on the traditional Fourier law and, further more, to the Biot’s wave equation without considering the heat phase. At last, the problem of one dimensional cylindrical cavity subjected to a time-dependent thermal/mechanical shock is analyzed by using the Laplace technique, the numerical results are used to discuss the influence of Biot’s modulus M and coefficient of thermoos-mosis on displacement and to compare with the results of thermo-elastodynamic response to ascertain the validity of this model.展开更多
基金supported by the National Natural Science Foundation of China (Grant 11172087)
文摘The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Euler-Bernoulli model with inextensible deformation. A nonlinear distributed parameter model of cantilevered piezoelectric energy harvesters is proposed using the generalized Hamilton＇s principle. The proposed model includes geometric and inertia nonlinearity, but neglects the material nonlinearity. Using the Galerkin decomposition method and harmonic balance method, analytical expressions of the frequency-response curves are presented when the first bending mode of the beam plays a dominant role. Using these expressions, we investigate the effects of the damping, load resistance, electromechanical coupling, and excitation amplitude on the frequency-response curves. We also study the difference between the nonlinear lumped-parameter and distributed- parameter model for predicting the performance of the energy harvesting system. Only in the case of parametric excitation, we demonstrate that the energy harvesting system has an initiation excitation threshold below which no energy can be harvested. We also illustrate that the damping and load resistance affect the initiation excitation threshold.
基金Supported by the National Natural Science Foundation of China (Grant No. 50679074) ZJ(NB)NSF (Grant Nos. Y107637, 2007A6100626)
文摘Based on the Biot’s wave equation and theory of thermodynamic, Darcy law of fluid and the modified Fourier law of heat conduction, a nonlinear fully coupled thermo-hydro-elastodynamic response model (THMD) for saturated porous medium is derived. The compressibility of the medium, the influence of fluid flux on the heat flux, and the influence of change of temperature on the fluid flux are considered in this model. With some simplification, the coupled nonlinear thermo-hydro-elastodynamic response model can be reduced to the thermo-elastodynamic (TMD) model based on the traditional Fourier law and, further more, to the Biot’s wave equation without considering the heat phase. At last, the problem of one dimensional cylindrical cavity subjected to a time-dependent thermal/mechanical shock is analyzed by using the Laplace technique, the numerical results are used to discuss the influence of Biot’s modulus M and coefficient of thermoos-mosis on displacement and to compare with the results of thermo-elastodynamic response to ascertain the validity of this model.
