Fractional Tajimi-Kanai model for simulating earthquake ground motion
Fractional Tajimi-Kanai model for simulating earthquake ground motion
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DOI：
10.1007/s10518-014-9615-z
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发表时间：
2014-12-01
影响因子：
4.6
通讯作者：
Pirrotta, A.
中科院分区：
文献类型：
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作者：
Alotta, G.;Di Paola, M.;Pirrotta, A.
地面加速度通常被建模为滤波高斯过程。最常见的模型是Tajimi-Kanai（TK）滤波器，它是一个粘弹性Kelvin-Voigt单元（与阻尼器平行的弹簧），携带由白色噪音（基岩加速度）激励的质量。基于每一种真实的材料在蠕变试验中都表现出幂律趋势的观察，本文提出用所谓的弹簧单元代替KelvinVoigt单元中的纯粘性单元，弹簧单元是一种由分数算子控制的介于纯弹性（弹簧）和纯粘性（阻尼器）之间的中间行为单元。通过这种选择，达到了两个主要目标：（i）地面的粘弹性行为可以简单地通过在给定场地的地面样本上进行蠕变（或松弛）测试来表征;（ii）对于经典TK模型，在自由场的绝对加速度的过零点的数量对于真正的白色噪声加速度，对于所提出的模型仍然是有限的。
The ground acceleration is usually modeled as a filtered Gaussian process. The most common model is a Tajimi-Kanai (TK) filter that is a viscoelastic Kelvin-Voigt unit (a spring in parallel with a dashpot) carrying a mass excited by a white noise (acceleration at the bedrock). Based upon the observation that every real material exhibits a power law trend in the creep test, in this paper it is proposed the substitution of the purely viscous element in the Kelvin Voigt element with the so called springpot that is an element having an intermediate behavior between purely elastic (spring) and purely viscous (dashpot) behavior ruled by fractional operator. With this choice two main goals are reached: (i) The viscoelastic behavior of the ground may be simply characterized by performing the creep (or the relaxation) test on a specimen of the ground at the given site; (ii) The number of zero crossing of the absolute acceleration at the free field that for the classical TK model is for a true white noise acceleration, remains finite for the proposed model.