基于连分式的基础高阶集中参数模型
High-order lumped-parameter models for foundation based on continued fraction
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摘要: 提出了两种基础振动分析的高阶集中参数模型。首先将近似基础频率响应的复频率有理函数展开为连分式;然后与模型动力刚度方程的连分式表达对比获得模型参数。相比于现有的高阶集中参数模型,两类模型容易扩展到高阶,其物理结构简洁并与所分析的问题无关。此外,由于模型的动力方程具有二阶时间导数项,因而应用本文模型的结构–基础–土系统可以采用显式时间积分求解。通过分析弹性地基表面半无限杆问题,并与Wu-Lee集中参数模型的结果进行比较,验证了本文模型的有效性。 更多还原Abstract: Two new types of high-order lumped-parameter models(LPMs) for foundation vibrations are proposed.The parameters of LPMs are obtained by comparing the continued-fraction dynamic-stiffness equations of new LPMs with the continued-fraction expansions of a rational function in complex frequency approximating foundation frequency response.Compared with the existing high-order LPMs,the proposed LPMs are easier to extend to high orders,and their physical configurations are condensed and independent of the problem analyzed.Moreover,due to the dynamic equations of LPMs with second-order derivative terms in time,the resulting structure-foundation-soil system can be solved by an explicit time-integration method.The effectiveness of the proposed LPMs is verified by analyzing the benchmark problem of semi-infinite rod on an elastic foundation and comparing with the results of Wu-Lee LPMs.