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为研究敦煌莫高窟彩塑在罕遇地震下的安全性,根据其内部构造特点,建立从内到外分别由木骨架层、芦苇捆扎层、粗泥层和细泥层组成的精细化有限元模型,通过扫频试验与模态分析结果对比,验证了所建有限元模型能够反应实际彩塑的动力特性。在此基础上计算罕遇地震作用下的响应,通过对模型的应力、位移和加速度结果的分析,评价彩塑的抗震性能。结果表明:罕遇地震下,站姿模型最大应力仍在允许范围内,但已接近破坏值,最容易出现破坏的地方主要为模型腿部以下区域、脖子周围以及上半身与手臂相连接部分;坐姿模型最大应力则发生在后背下部与底座连接的地方,其值超出了粗泥层和细泥层的抗拉强度,出现拉伸破坏。二者最大响应点均位于模型顶部,坐姿的响应小于站姿。可以认为在罕遇地震作用下彩塑存在损坏风险。
In order to study the safety of Mogao Grottoes in Dunhuang Mound under rare earthquakes, according to its internal structural features, a detailed finite element (FEM) structure consisting of wood skeleton layer, reed strapping layer, coarse mud layer and fine mud layer By comparing the results of the frequency sweep test and the modal analysis, it is verified that the finite element model can reflect the dynamic characteristics of the actual plastic-plastic. Based on this, the response of rare earthquakes is calculated. The stress and displacement of the model and the analysis of the acceleration results are used to evaluate the seismic performance of the plastic. The results show that under the rare earthquakes, the maximum stress of standing model is still within the allowable range. However, it is close to the damage value and the most prone to damage is the area below the leg, around the neck and between the upper body and the arm. The maximum stress of the model occurs at the place where the lower part of the back is connected to the base, whose value exceeds the tensile strength of the coarse mud and fine mud and tensile failure occurs. Both the maximum response points are located at the top of the model, the response of sitting position is less than the standing position. It can be considered that there is a risk of damage to the plastic in the rare earthquakes.