A new structural damage identification method using limited test static displacement based on grey system theory is proposed in this paper. The grey relation coefficient of displacement curvature is defined and used t...A new structural damage identification method using limited test static displacement based on grey system theory is proposed in this paper. The grey relation coefficient of displacement curvature is defined and used to locate damage in the structure, and an iterative estimation scheme for solving nonlinear optimization programming problems based on the quadratic programming technique is used to identify the damage magnitude. A numerical example of a cantilever beam with single or multiple damages is used to examine the capability of the proposed grey-theory-based method to localize and identify damages. The factors of meas-urement noise and incomplete test data are also discussed. The numerical results showed that the damage in the structure can be localized correctly through using the grey-related coefficient of displacement curvature, and the damage magnitude can be iden-tified with a high degree of accuracy, regardless of the number of measured displacement nodes. This proposed method only requires limited static test data, which is easily available in practice, and has wide applications in structural damage detection.展开更多
Unlike the Brock,Dechert,and Scheinkman(BDS)test,the Surrogate Data method is not only able to provide a nonlinearity test for exchange rates,but also distinguish whether the nonlinear features come from the economic ...Unlike the Brock,Dechert,and Scheinkman(BDS)test,the Surrogate Data method is not only able to provide a nonlinearity test for exchange rates,but also distinguish whether the nonlinear features come from the economic system itself.Our analysis gives some evidence on the presence of nonlinear dependency of five emerging markets' exchange rates by using BDS test.Furthermore,we present evidence in existence of intrinsic and deterministic nonlinearity in the five exchange rates using the Surrogate Data method,comparing the original data and surrogate data and rejecting the null hypothesis in confidence coefficient 95%.The results provide the basis for the analyses of the chaotic properties of exchange rate time series and their future nonlinear forecasting.展开更多
基金the National Natural Science Foundation of China(11801540)the Natural Science Foundation of Anhui(BJ2040170017)+4 种基金the Fundamental Research Funds for the Central Universities(WK2040000016)the Science and Technology Program of Guangzhou(202002030129)the Science and Technology Planning Project of Guangdong Province(2017A010101030)the National Key Research and Development Program of China(2018YFC1315400)the Third Medical Technology Projects of Shantou City in 2018(ShanFuKe【2018】128-08).
基金Project supported by the Natural Science Foundation of China(No. 50378041) and the Specialized Research Fund for the Doc-toral Program of Higher Education (No. 20030487016), China
文摘A new structural damage identification method using limited test static displacement based on grey system theory is proposed in this paper. The grey relation coefficient of displacement curvature is defined and used to locate damage in the structure, and an iterative estimation scheme for solving nonlinear optimization programming problems based on the quadratic programming technique is used to identify the damage magnitude. A numerical example of a cantilever beam with single or multiple damages is used to examine the capability of the proposed grey-theory-based method to localize and identify damages. The factors of meas-urement noise and incomplete test data are also discussed. The numerical results showed that the damage in the structure can be localized correctly through using the grey-related coefficient of displacement curvature, and the damage magnitude can be iden-tified with a high degree of accuracy, regardless of the number of measured displacement nodes. This proposed method only requires limited static test data, which is easily available in practice, and has wide applications in structural damage detection.
文摘Unlike the Brock,Dechert,and Scheinkman(BDS)test,the Surrogate Data method is not only able to provide a nonlinearity test for exchange rates,but also distinguish whether the nonlinear features come from the economic system itself.Our analysis gives some evidence on the presence of nonlinear dependency of five emerging markets' exchange rates by using BDS test.Furthermore,we present evidence in existence of intrinsic and deterministic nonlinearity in the five exchange rates using the Surrogate Data method,comparing the original data and surrogate data and rejecting the null hypothesis in confidence coefficient 95%.The results provide the basis for the analyses of the chaotic properties of exchange rate time series and their future nonlinear forecasting.
