论文部分内容阅读
近场竖向地震波富含各频率成分且具用较大的传播速度可能对结构造成较强的竖向脉冲效应。应用波动力学来分析脉冲型纵波激励作用下多自由度体系的动态响应时,其计算过程过于复杂且不容易收敛,而振动力学又无法反映波传播的时滞性和反射叠加效应,不能很好地反映这种脉冲效应和描述该类激励对结构造成的应力损伤。该文结合振动力学和波动力学的各自特点,针对简化的结构层模型并考虑了阻尼效应,推导了纵波通过楼板集中质量的反射和透射系数。在此基础上,对阻尼比、轴向刚度比和质量比对反射系数和透射系数的影响进行了参数分析,并对这些系数在土体-结构相互作用中的应用进行了初步的研究。研究结果表明:在反射和透射系数中考虑阻尼的影响是十分必要的,反射和透射系数的幅频曲线体现出了显著的高频滤波效应,且受轴向刚度比和质量比的影响也较大。这些研究工作为之后应用此简化波动方法计算脉冲型地震动竖向分量作用下结构的动力响应奠定了基础。
Near-field vertical seismic waves are rich in various frequency components and the use of large propagation velocities may cause strong vertical impulsive effects on the structure. Using wave mechanics to analyze the dynamic response of multi-degree-of-freedom system under impulsive P-wave excitation, the calculation process is too complicated and not easy to converge, while the vibration mechanics can not reflect the wave-propagation time lag and reflection superposition effect, which is not good Reflect this impulsive effect and describe the structural damage caused by such stimuli. According to the characteristics of vibration mechanics and wave mechanics, this paper deduces the reflection and transmission coefficient of the longitudinal wave passing through the slab mass concentration in consideration of the simplified structural model and considering the damping effect. On this basis, the parameters of damping ratio, axial stiffness ratio and mass ratio on the reflection coefficient and transmission coefficient are analyzed, and the application of these coefficients in the soil-structure interaction is preliminarily studied. The results show that it is necessary to consider the influence of damping in the reflection and transmission coefficients. The amplitude-frequency curves of the reflection and transmission coefficients show significant high-frequency filtering effects, which are also affected by the axial stiffness ratio and the mass ratio Big. These researches laid the foundation for the application of the simplified wave method to calculate the dynamic response of the structure under the vertical component of impulsive ground motion.