Rate-independent linear damping benefits low-frequency structures by mitigating excessive displacement without increasing the floor acceleration response under severe ground motions. The advantage of rate-independent linear damping in controlling low-frequency structures is attributed to its constant loss stiffness, which ensures high damping in low-frequency components while maintaining low high-frequency damping forces. In this study, a modal decomposition method was developed for a base-isolated structure containing rate-independent linear damping distributed non-proportionally to the stiffness. Because the response of a single-degree-of-freedom system containing rate-independent linear damping can be well-approximated by a linear viscous damping system having the same eigenvalues, the behavior of the rate-independent linear damping system can be evaluated via the response-spectrum approach. In the proposed modal analysis method, separated modal responses of a base-isolated structure were employed to demonstrate how rate-independent linear damping can achieve a displacement control effect similar to that of linear viscous damping with a low floor acceleration response. Compared with conventional frequency analyses, the proposed method was found to accurately predict the dynamic responses of a rate-independent linear damping system.

中文翻译：

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非比例分布速率无关线性阻尼多自由度结构的模态分解

与速率无关的线性阻尼通过减轻过度位移而无需增加剧烈地面运动下的地板加速度响应，从而有利于低频结构。速率无关线性阻尼在控制低频结构方面的优势归因于其恒定的损耗刚度，这确保了低频分量的高阻尼，同时保持较低的高频阻尼力。在本研究中，针对基础隔离结构开发了一种模态分解方法，该结构包含与刚度不成比例分布的速率无关线性阻尼。由于包含速率无关线性阻尼的单自由度系统的响应可以通过具有相同特征值的线性粘性阻尼系统很好地近似，因此速率无关线性阻尼系统的行为可以通过以下方式进行评估：响应谱方法。在所提出的模态分析方法中，采用基础隔震结构的分离模态响应来证明与速率无关的线性阻尼如何能够实现类似于具有低地板加速度响应的线性粘性阻尼的位移控制效果。与传统的频率分析相比，所提出的方法可以准确预测速率无关的线性阻尼系统的动态响应。