基于调频率的时-频非平稳地震动生成

动力时程分析是研究地震作用下结构响应的有效途径，而输入的地震动时程对计算结果有重要影响。实际地震动是时-频非平稳的随机过程，而目前用于结构动力时程分析的人工波多为时域非平稳频域平稳的时间时程。本文采用增加频率调制过程的方法对生成人工波的传统三角级数模型进行了改进，可使生成的地震动时程不仅是强度非平稳的，而且频率成分也是随时间变化的。改进方法生成的时-频非平稳地震动时程更接近于真实的地震动记录，且能很好地拟合目标反应谱，对工程实践具有重要意义。

Ground motion generation of nonstationary both in amplitude and frequency content based on frequency adjustment

Dynamic time-history analysis method is an effective way to study the structural response under the action of the earthquake. The precision of the input ground motion time-history has a major impact on the calculation results. The actual ground motions are non- stationary both in amplitude and frequency con- tent, but currently the artificial wave used for dynamic time-history analysis is stationary ground motion in frequency content. In this paper, an improved earthquake model as the product of a constant intensity pro- cess having time-varying frequency content and a deterministic intensity function is proposed. The new mod- el is achieved by adding frequency adjustment to the traditional triangular series model. The fully nonstation- ary ground motion generated by the new model is not only closer to the real earthquake records but also can fit the target response spectrum better, so it will he of great significance for the engineering practice.