设备地震响应的频谱分析法

目前设备抗地震分析一般有两种基本方法 :时程分析法和地震频谱法。文中以实例说明了如何运用有限元数值分析方法来实现频谱分析的步骤：首先进行模态分析，求得结构在地震频谱频率范围内的各阶固有频率；然后进行频谱分析，先求得对应于各阶固有频率的地震响应模态解 ,再进行模态解合并以得到结构对地震的总响应；再在后处理中进行工况组合得到包括地震载荷在内的各种工况的应力解、位移解。文中还参照ASME规范第Ш篇NF分篇的原则确定了不同工况组合下的应力极限。

Spectrum analysis method for seismic response of equipment

In this paper two methods for seismic response of equipment are compared, and the principal theory of the spectrum analysis method, which is widely used in engineering, is introduced. An example is given to illustrate the engineering application of the method. In spectrum analysis, first the mode result of each natural frequency can be calculated, and then, by mode combination, the system responses to the seismic can be obtained. And by the load-case analysis, the stress and deformation of the system for various load-cases including seismic loadings can be estimated. It is also discussed that how to define the stress limit to every assembling load-case according to ASME Code Section III, Subsection NF.