Dynamic Response Analysis For Showcase Of Cultural Relics Under Different Boundary Conditions

In order to strengthen the protection work of cultural relics, improve the domestic laws and regulations related to the protection of cultural relics and guide the work of cultural relics protection, protection of cultural relics was included in the national "twelfth five-year" plan and budget plan. The work sponsored by the state administration of cultural heritage, led by the Shanghai museum, the seismic code of cultural relics in the collection of museum is doing orderly. This article intends to regard the process of seismic waves spreading to the showcase from the floor as the research object, by ANSYS analysis of the model of five independent center showcases with sine excitation and seismic action. Give the acceleration dynamic magnification factors of showcase surface in different boundary conditions. Meanwhile, analyzing the influence of damping, friction coefficient, excitation amplitude and excitation frequency on the amplification coefficient. The main research content and conclusions include:Respectively using ANSYS to establish finite element model of fixed and floating condition, analysis the model with sine excitation and seismic action, and compared with the shaking table test and verify the correctness of the analysis method.Input sine excitation of fixed amplitude and different frequency (1-50Hz) for the showcase model, give the sine excitation frequency range to use guide the analysis of showcases. And give the acceleration dynamic magnification coefficient of limit Dg and DF of two kinds of boundary conditions in this frequency for booth surface. Summarize the rules that the dynamic magnification coefficient of booth surface changing with excitation frequency on two kinds of boundary conditions in this frequency.Input three seismic waves for the model, under the condition of constant height, with the change of the width, summarized the changing rule of the dynamic amplification coefficient, and under the action of earthquake, given the dynamic magnification coefficient of limit DG and DF on two kinds of conditions, further verify the rationality of the sine excitation frequency of given. This paper also analyzes the influence of damping, friction coefficient, excitation amplitude and excitation frequency on the amplification coefficient.Through the above analysis, the range of sine excitation frequency which is used to guide the analysis for showcases on the condition of fixed and floating can be within9Hz, In this frequency, the limit of acceleration dynamic magnification coefficient of booth surface on two kinds of boundary conditions DG is1.90and DF is2.60. And the dynamic magnification coefficient of booth surface increased with the increase of excitation frequency. For the law to the influence of excitation amplitude, with the increase of excitation amplitude dynamic magnification coefficient reduced. When the seismic wave function impact, amplitude have no obvious impact on the dynamic magnification coefficient. On the condition of single frequency excitation, the influence of amplitude in high frequency is obvious. Floating condition, when the horizontal friction is greater than the horizontal inertia force, the change of the friction coefficient and excitation amplitude have no effects on the dynamic magnification coefficient, and on this condition the dynamic response of fixed showcases is lower than floating situation. Whether fixed or floating, the acceleration dynamic magnification factor decreases with the increase of damping ratio.