为了更现实有效地解决求解结构地震反应的当前位移输入模型中容易但不容忽视的问题,进一步提出了一种新的解决方法--附加无质量刚性元法,旨在能够推广并应用于工程实际。首先,回顾当前求解结构地震反应的位移输入模型,描述了模型中存在的问题;然后,提出了无质量刚性元法,并对该方法进行物理角度解释、理论分析和数值验证,进一步应用于一桥梁工程。分析表明:无质量刚性元法不仅物理概念清晰、合理易行,而且与以往文献中的附加无质量束缚元(Appended Massless Constraint Element,AMCE)法相比,避免了"束缚"条件,无需对现有的有限元程序内核改进或者嵌入新的外挂程序即可实现,因此更具有现实性和推广意义。
A new method is presented and proposed to settle the problem, easy but not to be neglected, existing in the current displacement input model for the seismic-responses analysis of multi-degree-of-freedom multi-supported structures subjected to spatially ground motion. The method is called appended massless rigid element method. Firstly, the current displacement input model is reviewed, and the unnegligible problem inherent in it is described in detail. To solve the problem, the spring impedance method is presented. Then, the rationality and accuracy of the proposed method are further verified. Moreover, the method is applied to bridge engineering. Theoretical analysis and numerical results demonstrate that the proposed method is not only has the characteristics of explicit physical meaning, simplicity and feasibility, but also compared with the AMCE method in the previous literature. It avoids constraint condition and does not require additional improvement or subprogram for existing general finite element program. So, appended massless rigid element method is more realistic and is worthy to be generalized.