The problem of modeling for the linear structure with nonlinear boundary conditions in a more efficient manner is considered by proposing a novel condensation modeling method. The key idea of the proposed method is to reduce the overall number of degrees-of-freedom (DOFs) for the nonlinear jointed structure being analyzed, which can be implemented in the following two steps. Firstly, linear DOFs of the structure are truncated via finite element model reduction by using the free-interface mode synthesis method, as numerical integration of governing equations of structures with large numbers of DOFs is always time-consuming. Secondly, nonlinear DOFs at the boundary interface are reduced via coordinate condensation, so as to further minimize the model size of the structure being analyzed and make the subsequent analysis computationally efficient and memory economical. The performance of the proposed condensation modeling method is validated via case studies focused on an experimental structure with adjustable boundary conditions. Comparative results demonstrate that the computational efficiency can be extremely improved while the accuracy is simultaneously guaranteed by using the proposed method to model the linear structure with nonlinear boundary conditions.

通过提出一种新颖的缩合建模方法，可以考虑以更有效的方式对具有非线性边界条件的线性结构进行建模的问题。提出的方法的关键思想是减少所分析的非线性连接结构的自由度（DOF）总数，可以在以下两个步骤中实现该自由度。首先，通过使用自由界面模式综合方法，通过有限元模型简化，将结构的线性自由度截断，因为具有大量自由度的结构的控制方程的数值积分总是很耗时的。其次，边界坐标处的非线性自由度通过坐标凝聚而减少，以便进一步最小化所分析结构的模型大小，并使后续分析在计算上高效且节省内存。通过案例研究验证了所提出的冷凝建模方法的性能，该案例研究的重点是具有可调边界条件的实验结构。比较结果表明，通过使用所提出的方法对具有非线性边界条件的线性结构进行建模，可以极大地提高计算效率，同时保证精度。