MDOFS累积塑性变形能的理论研究与敏感性分析

Theoretical study and sensitivity analysis on the cumulative-plastic deformation energy in MDOFS

为了研究多自由度体系(MDOFS)累积塑性变形能的分布规律,基于能量平衡原理和多模态等效单自由度体系(ESDOFS)的概念,推导了MDOFS累积塑性变形能需求量及其沿结构各层的分配系数。在此基础上,综合考虑地震作用下结构局部破坏或损伤情况,进行了16种工况下的敏感性分析,得出结构各层参数对累积塑性变形能分布的敏感性影响规律。结果表明:累积塑性变形能分配系数主要由质量(mi)、屈服剪力系数(αi)、刚度(ki)和累积延性系数(ηi)四个因素决定;顶层参数变化对累积塑性变形能分布无明显影响;逐层递减和中间层薄弱情况下,各层分配的累积塑性变形能与αi和ηi呈正相关,与ki呈反相关;中间薄弱层释放的累积塑性变形能按其相邻两层原累积塑性变形能大小之比进行重新分配。

To explore the distribution of the cumulative-plastic deformation energy in multi degrees of freedom system （MDOFS）,the demand for the cumulative-plastic deformation energy as well as the distribution coefficient along the layers were derived.Furthermore,a sensitivity analysis was carried out under 16 working conditions,taking all the possibilities of local failure or damage into account.And then the sensitivity influencing was discussed.The results show that the distribution coefficient of the cumulative-plastic deformation energy is mainly determined by the gravity（mi ）,the yield shear coefficient（αi ）,the stiffness（ki ）and the cumulative-plastic deformation ratio（ηi ）.The top floor parameters have no significant effect on the distribution of the cumulative-plastic deformation energy.In the case of energy decreasing layer by layer or the weak middle floor,the cumulative-plastic deformation energy distribution is positively correlated withαi and ηi ,and negatively correlated with ki ,respectively.The cumulative-plastic deformation energy released from the weak middle floor will be redistributed to the neighboring layers according to the portions of the initial cumulative-plastic deformation energy obtained by these layers.