基于FK-FE混合方法的位错点源作用下全过程结构地震反应模拟

END-TO-END STRUCTURAL SEISMIC RESPONSE SIMULATION UNDER ACTION OF SEISMIC DISLOCATION UPON FK-FE HYBRID METHOD

基于区域缩减思想,集整基于精确动力刚度矩阵的频率波数域(FK)半解析方法和有限元(FE)数值方法各自优势(FK精确高效模拟一维波速结构地震波传播;FEM具有丰富单元和本构类型,可精细模拟工程结构地震反应),提出了一种从震源到工程结构全过程地震反应模拟的FK-FE混合方法。并将FK代码作为插件二次开发到大型商业有限元软件ABAQUS中,实现了ABAQUS平台下从震源到工程结构的全过程宽频地震反应物理模拟。验证了FK-FE混合方法正确性,进而将其应用于位错点源作用下美国SAC机构设计的9层Benchmark抗弯钢框架结构全过程0 Hz~15 Hz宽频地震反应模拟,重点探讨了地壳层波速结构和近地表场地条件对框架结构地震反应的影响。研究表明:地壳层速度结构和场地类别对该结构的地震反应均有显著影响,地壳层速度结构3(较硬)相比速度结构1(较软),结构最大位移和层间位移角分别减小了22.7%和62.0%;Ⅱ类场地相较于Ⅳ类场地,结构最大位移和层间位移角分别减小了22.3%和44.7%。

Upon the domain reduction idea,the FK-FE hybrid method is proposed to simulate the end-to-end structural seismic analysis by combing the merits of the semi-analytical frequency-wavenumber(FK)method and the finite element(FE)method.The FK approach,constructed by the exact dynamic stiffness matrix,can accurately and effectively simulate wave propagation in an 1D velocity structure.The finite element method can finely simulate seismic response of engineering structures due to its rich elements and constitutive.ABAQUS,a large-scale commercial finite element software,is secondarily developed by adding the FK code as a plug-in to reach the physical-based simulation of the end-to-end broadband seismic response.The FK-FE hybrid method is well verified and then applied to simulate the 0 Hz~15 Hz broadband seismic response of the 9-story Benchmark moment-resisting steel frame,designed by the American SAC,under the action of seismic dislocation.The influence of crustal velocity structure and site classes on the structural seismic response is discussed.The results show that the crustal velocity structure and the site classes significantly impact the structural displacement and the inter-story drift angle under the seismic dislocation.Compared with the case of soft crust(velocity structure 1),both the maximum structural displacement and the maximum inter-story drift angle are reduced by 22.7%and 62.0%in the hard crust(velocity structure 3),respectively.While for the case of site classes,those in site classⅡare reduced by 22.3%and 44.7%,respectively,compared with the class Ⅳ.