Research On Random Vibration Method For Seismic Analysis Of Nuclear Power Engineering Structures

It is a new research field in civil engineering to apply random vibration methods to seismic designs of nuclear power engineering structures.In general,seismic actions are considered as equivalent static loads or deterministic dynamic loads.However,the occurence place,time and process of earthquakes have strong randomness in fact.It is more realistic to consider seismic input to be a stochastic process.In the light of the importance of nuclear engineering,it is of great theoretical significance and engineering application value to study seismic responses of structures using random vibration methods.In this paper,based on a newly-developed efficient random vibration method in recent years,namely,time-domain explicit random simulation method,researches on random seismic analyses and dynamic reliability analyses are conducted systematically for nuclear power engineering structures.Based on time-domain explicit random simulation method,a calculation software is developed for seismic analyses of nuclear power engineering structures.This method is successfully applied to seismic analyses of nuclear power engineering structures.The main contents of this dissertation can be described as follows:(1)At first,literature review is carried out on the research of random vibration analysis methods,structural dynamic reliability analyses and seismic analyses of nuclear power engineering structures.Various methods of random vibration is introducted,and analysis methods of structural dynamic reliability are summarized.The recent developments in the area of seismic analyses of nuclear power engineering structures are reviewed,including seismic input and seismic analysis methods.(2)Time-domain explicit random simulation method is elaborated systematically for nonstationary random seismic response analyses and seismic reliability analyses.The derivation process is introduced for time-domain explicit expressions of structural dynamic responses.The primary procedures are studied emphatically,including estabilishment for coefficient vectors of time-domain explicit expressions,generation of samples of non-stationary ground motion acceleration process and random simulation of critical responses.Time-domain explicit random simulation method is used for seismic dynamic reliability analyses.Then,seismic dynamic reliability analysis is further researched considering the parameter randomness of material strength.(3)Resarch on seismic analyses of nuclear power engineering structures is conducted systematically using time-domain explicit random simulation method.According to the seismic safety evaluation report of the site for the considered nuclear engineering project,the equivalent power spectral density with the design acceleration response spectrum is derived.The finite element model of the nuclear power plant structure is established using the general-purpose finite element analysis software,and the time-domain explicit expressions of structural dynamic responses are obtained using the pulse response method.On this basis,random seismic analysis and dynamic reliability analysis are carried out using time-domain explicit random simulation method for the considered nuclear engineering project,and meaningful results are obtained,illustrating the feasibility of time-domain explicit random simulation method for seismic analyses of nuclear enginnering structures.(4)Based on time-domain explicit random simulation method,a calculation software is developed for seismic analyses of nuclear power engineering structures.The software development platform,the overall software architecture,the software modules and their functions and characteristics are introduced in detail.The developed software provides an effective computing platform for random seismic analyses of nuclear power engineering structures.