Papers by Keyword: Anti-Resonance

Abstract: The operation principle of anti-resonance vibration machine was analyzed. The dynamic model of anti-resonance vibration machine with nonlinear spring was established. A new method for solving nonlinear equation based on general finite element method was put forward, the solution was compared with numerical solution, the validity of the solving method was validated. Then the affection of nonlinear and dynamics parameters to the amplitude stabilization was analyzed. the conclusion can be drown as: when the anti-resonance frequency ratio is 1~2,increase the nonlinear of spring can improve the amplitude stabilization, when the anti-resonance ratio is bigger than 3,there is less affection to the amplitude stabilization by nonlinear of spring. The amplitude stabilization can be improved by increasing anti-resonance frequency ratio.

Abstract: Cracks bring a serious threat to safety of structures. Most of the failures and fractures of engineering structures are due to initial cracks or fatigue cracks of materials. So it is very important to analyze the vibration characteristics and to identify the damage of cracked structures. A method for multi-crack identification based on wave propagation is proposed in this paper, which makes use of the driving-point mechanical impedance characteristics of the cracked beams stimulated by harmonic force. The proposed identification method is used to characterize the local discontinuity due to cracks, and a simplified rotational spring model is introduced to model cracks. Subsequently, the proposed method is verified by a numerical example of a simply supported steel beam with three cracks. The effect of crack depth on driving-point impedance is investigated. Combined with the first anti-resonances information, the proposed method can identify the presence of cracks, localize the multiple cracks, and qualitatively identify the extent of the crack damages.