This paper presents the use of infinite element boundary conditions for physical and engineering problems in a three-dimensional unbounded domain, subjected to seismic loading, with a view to compare results with the traditional viscous boundary. Boundary conditions are discussed in general with an emphasis on understanding the pros and cons of each method used. Also, a comparison is drawn between the different types of boundary conditions used for the optimal solution of physical problems especially the models under seismic loading. Infinite elements can be implemented easily with lesser computational time. It provides “quite” boundaries to the models and can be used effectively for the accurate numerical solutions of physical issues. This paper presents the complete details of node setting and numerical computation for the infinite element boundaries and compares results of a three-dimensional free field soil model and a soil–tunnel model under seismic loading using infinite boundary, and a similar model using a spring/dashpot system. The results verified the use infinite element boundary to evaluate the seismic behaviour of the model and suggest that in the time domain, this method can be combined easily with the finite element and other methods such as boundary element method directly.

中文翻译：

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地震作用下动力学模型的无限元边界条件

本文介绍了无限元边界条件在地震荷载作用下三维无边界域中物理和工程问题的应用，目的是将结果与传统粘性边界进行比较。通常讨论边界条件，重点是理解每种方法的优缺点。此外，还对用于最佳解决物理问题（尤其是地震荷载下的模型）的各种边界条件进行了比较。可以用更少的计算时间轻松实现无限元素。它为模型提供了“相当大的”边界，可以有效地用于物理问题的精确数值解。本文介绍了无限单元边界的节点设置和数值计算的完整详细信息，并比较了无限载荷下三维自由场土壤模型和土-隧道模型在无限载荷下的结果，以及使用弹簧/阻尼系统。结果验证了使用无限元边界评估模型的抗震性能，并表明在时域中，该方法可以轻松地与有限元以及边界元法等其他方法轻松组合。