【作者】 刘英亮；

【导师】 邢佶慧；

【作者基本信息】 北京交通大学 ， 结构工程， 2011， 硕士

【摘要】 基于多自由度体系的能量平衡方程,对ANSYS软件进行二次开发,编制相应的前、后处理程序,采用非线性时程分析方法,通过数值积分提取网壳结构地震过程中结构各项能量响应及地震动总输入能的时间历程,观察其罕遇地震作用下的响应及破坏规律,研究网壳结构的破坏状态与耗能之间的关系,分析地震动持时对地震动总输入能大小及各项能量响应的影响,获取地震能量输入与结构能量耗散间的相互关系,为寻求基于能量的结构抗震设计方法和完善结构位移—能量双重动力破坏准则提供了依据。将响应面法引入到网壳结构可靠度计算中,通过MATLAB编程实现可靠度和验算点的计算,基于位移—能量双参数准则,可准确预测网壳结构动力破坏荷载,避免全过程曲线方法多次时程分析计算的缺点,提高计算效率。研究表明,地震动持时不同,各能量的转化及比例关系不同,单层球面网壳结构进入塑性后,动能与弹性变形能对总耗能的影响很小,非弹性滞回耗能所占比例逐渐增大。处于动力极限状态时,网壳结构的耗能供给能力达到极限,其非弹性滞回耗能剧增,各项能量之和超过总输入能。采用响应面法进行预测,结构基本变量的方差变化时,对预测结果影响不大,但方差越大,可靠度越低,对于单层鞍形网壳结构建议取破坏指标D大于0.7时的采样中心。更多还原

【Abstract】 In this paper, the energy formulation of multiple freedom system is utilized. Based on energy concept, pre-program and post-program of FEM software ANSYS are edited to extract each kind of energy dissipation and total inputting energy during the dynamic non-linear time-history calculation of the shells subjected to severe earthquakes. As a result, the dynamic response regularities and damage characteristic of such structures are obtained. The relationship between the dynamic failure and the dissipation of the inputting earthquake energy of the shells is proposed. Furthermore, the effect of earthquake duration is also investigated. The paper provides some basis for the developing of anti-seismic structure design method and Double-Failure Criteria based on the first surpass of maximum displacement and plastic accumulative damage. In order to solve the reliability of the shells, the Response Surface Methodology is introduced on this paper. The solving of the reliability and the checking point is based on the Double-Failure Criteria by MATLAB programming. The prediction of the shells’dymatic failure load is accurate, avoids solving so many times by the time-history calculation, and improves the solving efficiency. The research result shows that when the duration time of earthquakes is changed, the transformation and the proportion relation of every kind of energies will be changed. and the damping energy accounts for a large part in the elastic stage, while the proportion of the kinetic energy and the strain energy is relatively small. In the plastic stage, the proportion of the nonlinear hysteretic exhausted energy gradually increases, conversely the part of damping decreases. When the structures are on the dymatic limit state, the proportion of the nonlinear hysteretic exhausted energy will leap and the summation of every kind of energies will become larger than total inputting energy. Based on the Response Surface Methodology, the change on the variance of the basic random has little effect on the predicted results. The reliability becomes small when the variance becomes large.The suggestion is that D must larger than 0.7 in sampling points for single-layer saddle-shaped reticular shells.更多还原