Parametric Instability of a Beam Under Electromagnetic Excitation

Dynamic instability of composite beams under parametric excitation

“…(6) are of symmetric form. Therefore, the combination resonance of difference type does not occur [19]. Besides, the critical damping coefficient of the system can be found by comparing the analytical results with the experimental ones.…”

“…In this paper, the parametric instability of graphite/epoxy composite beams under parametric excitation was investigated experimentally and analytically by extending the similar work done for metal beams [19]. In analysis, the system dynamic equation of composite beams was derived first; then the instability bandwidths were obtained.…”

“…After connecting the spring kðtÞ to the system, as shown in Fig. 1, the system dynamic equation can be obtained from the LagrangeÕs equation [19] € q n ðtÞ þ d n _ q n ðtÞ þ x 2 n q n ðtÞ þ kðtÞ…”

“…If the experiments are focused on the systems subjected to a periodically axial loading, the instability regions of these problems are easily affected by the geometric imperfection of the composite beam axis, the coupling effects between the excitation mechanism and the specimen, and the eccentricity of the axial load. In this work, an electromagnetic device [19] was used and treated as a non-contacting electromagnetic excitation force in the transverse direction. Hence, the disturbances induced from the geometric imperfection of the composite beam, the eccentricity of the axial force and the coupling effects between the excitation mechanism and the composite beam were effectively avoided.…”

Experimental study on dynamic buckling phenomena for supercavitating underwater vehicle

“…Regarding dynamic buckling (parametric resonance) theory, one can resort to references (Ahn and Ruzzene, 2006;Bolotin, 1964;Iwatsubo and Saigo, 1974;Park and Kim, 2002;Popov, 2003). However, regarding how to construct dynamic buckling test system, the issue is not sufficiently dealt with, although there are some references (Chen and Yeh, 2001;Deolasi and Datta, 1997;Langthjem and Sugiyama, 2000). In the line of thought, a dynamic buckling test system is developed and its validity and conceptual usefulness are investigated in this work.…”