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阻尼是结构动力分析的重要参数,对动力响应计算的结果有明显影响。目前,结构动力响应分析中的阻尼模型大都采用的是传统的Rayleigh阻尼模型,这种模型是为计算解耦而构造出的,其物理意义不是很明确。该文根据复阻尼系统理论,利用Newmark-β积分法,编制了Rayleigh阻尼和复阻尼模型的三维有限元程序。以三维钢框架结构为研究对象,计算了两种阻尼模型的结构地震时程响应和复阻尼模型的损耗因子,并讨论了不同加速度峰值和时间积分步长对复阻尼结构响应和损耗因子的影响。研究表明:在加速度峰值为2m/s2的El-Centro波作用下,两种阻尼模型的响应相差50%―100%,后者的结构动力响应远大于前者,损耗因子随应力或位移的增大而增大;复阻尼模型结构动力响应和损耗因子的稳定性和精度,与时间积分步长密切相关,不合适的时间积分步长将导致结果发散。
Damping is an important parameter of structural dynamic analysis, which has obvious influence on the result of dynamic response calculation. At present, most of the damping models in the structural dynamic response analysis use the traditional Rayleigh damping model, which is constructed for the decoupling calculation. Its physical meaning is not very clear. According to the theory of complex damping system, a three-dimensional finite element program of Rayleigh damping and complex damping model is developed by Newmark-β integration method. Taking the 3D steel frame structure as the research object, the structural seismic time-history response and the complex damping loss factor of two damping models are calculated. The effects of different acceleration peaks and time integral steps on the response and dissipation factor of the complex damping structure are discussed. . The results show that under the action of El-Centro wave with peak acceleration of 2m / s2, the response of the two damping models varies by 50% -100%, the dynamic response of the latter is far greater than the former, and the loss factor increases with the stress or displacement The stability and accuracy of the dynamic response and loss factor of the complex damping model are closely related to the time integral step, and the unsuitable time integration step will cause the result to diverge.