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力学学报 2002
ELASTIC DEFORMATION EFFECTS ON DYNAMIC RESPONSE OF A ELASTIC-PLASTIC CIRCULAR PLATE UNDER IMPULSIVE LOAD
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Abstract:
By employing the finite difference method to numerically solve the governing differential equation in its discrete form, the dynamic response is studied for an elastic, perfectly-plastic (e-p-p) clamped circular plate subjected to impulsive loading. The elastic effects on the deformation mechanism of the plate are discussed through carefully analyzing the instantaneous distribution of the radial bending moment during early time response.It can be seen from the present analysis that the deformation mechanisms of an impulsively loaded elastic-plastic plate consist of eight phases, i.e. "Single plastic hinge-ring" mode; "Double plastic hinge-ring" mode; "Five plastic hinge-ring" mode; "Four plastic hinge-ring" mode; "Three plastic hinge-ring" mode; "Double plastic hinge-ring" mode; "Double stationary plastic hinge-ring mode; "Elastic vibration" mode. Through a comparison with the three phase's deformation mode obtained by using rigid, perfectly-plastic (r-p-p) approach, the "stationary plastic hinge-ring" mode at the clamped boundary is verified by e-p-p analysis. The second phase and the third phase in r-p-p analysis can also be observed in the present e-p-p analysis while the first phase is not found. Since the duration of response of the second and third phase in the r-p-p analysis and the corresponding phase in e-p-p analysis is relatively long, the primary feature of the deformation mechanisms are accordant for both of the analysis methods.The elastic effects not only result in the "travelling plastic hinge-ring" moving back and forth but also make its number increase to 3. In addition, also as the elastic influence, the sign of the "stationary plastic hinge-ring" at the center of the plate changes alternately from negative to positive. Therefore, the elastic effects on the deformation history of the impacted plate are significant.