The authors have developed a two-dimensional model for the extension and flexure response of electroelastic plates under biasing fields in a curvilinear coordinate system. Applications of the model in analyzing buckli...The authors have developed a two-dimensional model for the extension and flexure response of electroelastic plates under biasing fields in a curvilinear coordinate system. Applications of the model in analyzing buckling of two circular piezoelectric plates, one single-layered and the other double-layered, are included. The analysis indicates that the piezoelectric coupling has a strengthening effect against buckling.展开更多
An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper. Unlike the natural frequency, the anti-resonant frequency is a local parameter r...An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper. Unlike the natural frequency, the anti-resonant frequency is a local parameter rather than a global parameter of structures, thus the proposed technique can be used to locate the structural defects. An impedance analysis of a cracked beam stimulated by a harmonic force based on the Timoshenko beam formulation is investigated. In order to characterize the local discontinuity due to cracks, a rotational spring model based on fracture mechanics is proposed to model the crack. Subsequently, the proposed method is verified by a numerical example of a simply-supported beam with a crack. The effect of the crack size on the anti-resonant frequency is investigated. The position of the crack of the simply-supported beam is also determined by the anti-resonance technique. The proposed technique is further applied to the ＂contaminated＂ anti-resonant frequency to detect crack damage, which is obtained by adding 1-3% noise to the calculated data. It is found that the proposed technique is effective and free from the environment noise. Finally, an experimental study is performed, which further verifies the validity of the proposed crack identification technique.展开更多
基金the National Natural Science Foundation of China(No.10172036)the Office of US Naval Research(Contract No.ONR N00014-96-1-0884)
文摘The authors have developed a two-dimensional model for the extension and flexure response of electroelastic plates under biasing fields in a curvilinear coordinate system. Applications of the model in analyzing buckling of two circular piezoelectric plates, one single-layered and the other double-layered, are included. The analysis indicates that the piezoelectric coupling has a strengthening effect against buckling.
基金Project supported by the National Natural Science Foundation of China(No.50608036)Program for New Century Excellent Talents in Universities.
文摘An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper. Unlike the natural frequency, the anti-resonant frequency is a local parameter rather than a global parameter of structures, thus the proposed technique can be used to locate the structural defects. An impedance analysis of a cracked beam stimulated by a harmonic force based on the Timoshenko beam formulation is investigated. In order to characterize the local discontinuity due to cracks, a rotational spring model based on fracture mechanics is proposed to model the crack. Subsequently, the proposed method is verified by a numerical example of a simply-supported beam with a crack. The effect of the crack size on the anti-resonant frequency is investigated. The position of the crack of the simply-supported beam is also determined by the anti-resonance technique. The proposed technique is further applied to the ＂contaminated＂ anti-resonant frequency to detect crack damage, which is obtained by adding 1-3% noise to the calculated data. It is found that the proposed technique is effective and free from the environment noise. Finally, an experimental study is performed, which further verifies the validity of the proposed crack identification technique.
