馆藏浮放陶瓷文物地震摇晃响应振动台试验

Response to oscillation of a free-standing museum cultural relic under earthquake conditions by shaking table tests

为保护可移动文物，采取试验方法研究了地震作用下馆减浮放文物的摇晃响应。以故宫某展柜为原型，制作了1：1比例的模型，并在展柜内放置了一陶瓷文物，进行了振动台试验。通过白噪声激励，获得了展柜的基频；通过输入不同类型、不同强度的地震波，研究了展柜和文物的地震响应；通过数值模拟，从理论上对模型地震响应进行了进一步论证。结果表明：对展柜而言，其基频在29～35Hz之间，与地震波卓越频率相差较大，因而在地震作用下摇晃不明显；对文物而言，在地震波强度较小时能保持稳定振动状态，而在地震波强度较大时，文物容易产生明显摇晃并导致倾覆。此外，数值模拟结果与振动台试验结果吻合，证明了试验方法的有效性。在实际工程中，对高宽比较大的文物，应采取适当的加固措施，以减轻其摇晃震害。

With the aim of protecting movable cultural relics, the response to oscillation of a free - standing muse- um cultural relic under earthquake conditions was studied mainly by shaking table tests. A 1 ： 1 scale model of a showcase in the Palace Museum was built. A free -standing ceramic cultural relic was put in the showcase. Using white noise excitation, frequency distributions of the showcase were obtained. Then the seismic responses of both showcase and relic were studied by inputting 3 different types of earthquake waves with different intensities. Using simulation methods, finite elemental models for the showcase and relic were built and modal as well as time history analyses were carried out to validate the efficacy of shaking table tests. The results show that prominent frequency ingredients of the showcase are between 29 to 35Hz,which were far from those of input earthquake waves; thus the showcase is not damaged seriously, For the relic itself, when input earthquake intensity is low, it is relatively stable, but when earthquake intensity increases, its response to oscillation becomes obvious, and it even overturns under strong earthquake conditions. Thus the simulation results are good in accordance with those of shaking table tests, which proved efficacy of the test method. In real cases, i. e. , for movable cultural relics with a large height - to - with ratio, measures have to be taken to reduce its amplitude of oscillation.