For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power s...For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power spectrum density function （EPSD） of a random excitation was given by wavelet transform. Based on the EPSD, the nonstationary responses of a SDOF system subjected to evolutionary random excitations were studied. The application and validity of presented method were illustrated by numerical examples. In numerical examples, the recently developed stochastic models for El Centro （1934） and Mexico City （1985） earthquakes which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations were used as excitations. The nonstationary random mean-square responses of a SDOF system under these two excitations were evaluated and compared with simulated results.展开更多
In order to study the dynamic response of concrete-filled steel tube(CFST) columns against blast loads,a simplified model is established utilizing the equivalent single-degree-of-freedom(SDOF) method,which considers t...In order to study the dynamic response of concrete-filled steel tube(CFST) columns against blast loads,a simplified model is established utilizing the equivalent single-degree-of-freedom(SDOF) method,which considers the non-uniform distribution of blast loads on real column and the axial load-bending moment(P-M) interaction of CFST columns.Results of the SDOF analysis compare well with the experimental data reported in open literature and the values from finite element modeling(FEM) using the program LS-DYNA.Further comparisons between the results of SDOF and FEM analysis show that the proposed model is effective to predict the dynamic response of CFST columns with different blast conditions and column details.Also,it is found that the maximum responses of the columns are overestimated when ignoring the non-uniformity of blast loads,and that neglecting the effect of P-M interaction underestimates the maximum response of the columns with large axial load ratio against close range blast.The proposed SDOF model can be used in the design of the blast-loaded CFST columns.展开更多
Integrated development of industrial cooperation is the core content in the Bohai economic rim.Industrial structure convergence of Bohai economic rim mainly exist in macro three industries while it rarely exist in the...Integrated development of industrial cooperation is the core content in the Bohai economic rim.Industrial structure convergence of Bohai economic rim mainly exist in macro three industries while it rarely exist in the manufacturing industry and other internal meso level. Learning from changing tendency, industrial structure convergence in the five provinces and municipality in the Bohai Economic Rim tend to be increasingly intense. For integration of industry cooperation development in Bohai Economic Rim, it is faced with massive separation, industrial development convergence and is restricted by institutional and ideological barriers. As strategic choice based on interest tending, integration of industry cooperation development in Bohai Economic Rim should be further integrated on development concept of industrial transformation to promote institutional system of the integration of industrial development and optimize the industrial layout and division system of Bohai economic rim.展开更多
Rheological behavior of this article presents rapeseed oil. Dynamic viscosity of rapeseed oil was determined at temperatures between 40 ℃-90 ℃ and shear rates ranging from 3.3-120 s1. All types of oils studied Bingh...Rheological behavior of this article presents rapeseed oil. Dynamic viscosity of rapeseed oil was determined at temperatures between 40 ℃-90 ℃ and shear rates ranging from 3.3-120 s1. All types of oils studied Bingham fluid behavior in the temperature range from 313-363 K. Correlation coefficients have similar values to one for all oils studied.展开更多
文摘For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power spectrum density function （EPSD） of a random excitation was given by wavelet transform. Based on the EPSD, the nonstationary responses of a SDOF system subjected to evolutionary random excitations were studied. The application and validity of presented method were illustrated by numerical examples. In numerical examples, the recently developed stochastic models for El Centro （1934） and Mexico City （1985） earthquakes which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations were used as excitations. The nonstationary random mean-square responses of a SDOF system under these two excitations were evaluated and compared with simulated results.
基金Project(KJZH14220)supported by the Achievement Transfer Program of Institutions of Higher Education in Chongqing,China
文摘In order to study the dynamic response of concrete-filled steel tube(CFST) columns against blast loads,a simplified model is established utilizing the equivalent single-degree-of-freedom(SDOF) method,which considers the non-uniform distribution of blast loads on real column and the axial load-bending moment(P-M) interaction of CFST columns.Results of the SDOF analysis compare well with the experimental data reported in open literature and the values from finite element modeling(FEM) using the program LS-DYNA.Further comparisons between the results of SDOF and FEM analysis show that the proposed model is effective to predict the dynamic response of CFST columns with different blast conditions and column details.Also,it is found that the maximum responses of the columns are overestimated when ignoring the non-uniformity of blast loads,and that neglecting the effect of P-M interaction underestimates the maximum response of the columns with large axial load ratio against close range blast.The proposed SDOF model can be used in the design of the blast-loaded CFST columns.
文摘Integrated development of industrial cooperation is the core content in the Bohai economic rim.Industrial structure convergence of Bohai economic rim mainly exist in macro three industries while it rarely exist in the manufacturing industry and other internal meso level. Learning from changing tendency, industrial structure convergence in the five provinces and municipality in the Bohai Economic Rim tend to be increasingly intense. For integration of industry cooperation development in Bohai Economic Rim, it is faced with massive separation, industrial development convergence and is restricted by institutional and ideological barriers. As strategic choice based on interest tending, integration of industry cooperation development in Bohai Economic Rim should be further integrated on development concept of industrial transformation to promote institutional system of the integration of industrial development and optimize the industrial layout and division system of Bohai economic rim.
文摘Rheological behavior of this article presents rapeseed oil. Dynamic viscosity of rapeseed oil was determined at temperatures between 40 ℃-90 ℃ and shear rates ranging from 3.3-120 s1. All types of oils studied Bingham fluid behavior in the temperature range from 313-363 K. Correlation coefficients have similar values to one for all oils studied.
