This paper presents a generalized form of the method of full approximation. By using the concept of asymptotic linearization and making the coordinate transformations including the nonlinear functionals of dependent v...This paper presents a generalized form of the method of full approximation. By using the concept of asymptotic linearization and making the coordinate transformations including the nonlinear functionals of dependent variables, the original nonlinear problems are linearized and their higher-order solutions are given in terms of the first-term asymptotic solutions and corresponding transformations. The analysis of a model equation and some problems of weakly nonlinear oscillations and waves with the generalized method shows that it is effective and straightforward.展开更多
Using effective width of load and distribution coefficient of moment is a kind of simplified method in the design of continuous reinforced concrete slabs, which is widely used in engineering design. In this paper, thr...Using effective width of load and distribution coefficient of moment is a kind of simplified method in the design of continuous reinforced concrete slabs, which is widely used in engineering design. In this paper, through the analysis of load-bearing states of continuous slabs restricted by the main beams under concentrated loads, the effective width of load and distribution coefficients of moment of a continuous slab are obtained with the principle of equivalent loads. On the basis of the data of a 5-span continuous reinforced concrete slab, the formula of effective width is deduced and the distribution coefficients of moment for the mid-span and supports are given.展开更多
The spatial resolution of conventional distributed fiber optic sensors is 1 m at best, which is inadequate to locate the damage precisely. We adopt an improved sensing technique based on the Brillouin optical time-dom...The spatial resolution of conventional distributed fiber optic sensors is 1 m at best, which is inadequate to locate the damage precisely. We adopt an improved sensing technique based on the Brillouin optical time-domain analysis （BOTDA）. The stepped pump light is input to stimulate the phonon so that the spatial resolution can be increased to centimeter order and the strain accuracy of 25 micro-strains is obtained. The feasibility of this sensing technique is demonstrated through strain measurement of three concrete box-girders in bending. Experimental results show that the improved BOTDA measurement can provide a comprehensive description on the strain distribution of steel rebar or concrete. Compared with the conventional strain gauges, the improved BOTDA measurement is more stable. By virtue of higher spatial resolution and better measurement accuracy, it has become possible to perform crack detection and localization for concrete structures.展开更多
基金Project Supported by National Natural Science Foundation of ChinaMunicipal Natural Science Foundation of Shanghai
文摘This paper presents a generalized form of the method of full approximation. By using the concept of asymptotic linearization and making the coordinate transformations including the nonlinear functionals of dependent variables, the original nonlinear problems are linearized and their higher-order solutions are given in terms of the first-term asymptotic solutions and corresponding transformations. The analysis of a model equation and some problems of weakly nonlinear oscillations and waves with the generalized method shows that it is effective and straightforward.
文摘Using effective width of load and distribution coefficient of moment is a kind of simplified method in the design of continuous reinforced concrete slabs, which is widely used in engineering design. In this paper, through the analysis of load-bearing states of continuous slabs restricted by the main beams under concentrated loads, the effective width of load and distribution coefficients of moment of a continuous slab are obtained with the principle of equivalent loads. On the basis of the data of a 5-span continuous reinforced concrete slab, the formula of effective width is deduced and the distribution coefficients of moment for the mid-span and supports are given.
基金supported by the National Natural Science Foundation of China (Nos.50725828 and 50608017)the Sustentation Fund for Young Teachers of Southeast University
文摘The spatial resolution of conventional distributed fiber optic sensors is 1 m at best, which is inadequate to locate the damage precisely. We adopt an improved sensing technique based on the Brillouin optical time-domain analysis （BOTDA）. The stepped pump light is input to stimulate the phonon so that the spatial resolution can be increased to centimeter order and the strain accuracy of 25 micro-strains is obtained. The feasibility of this sensing technique is demonstrated through strain measurement of three concrete box-girders in bending. Experimental results show that the improved BOTDA measurement can provide a comprehensive description on the strain distribution of steel rebar or concrete. Compared with the conventional strain gauges, the improved BOTDA measurement is more stable. By virtue of higher spatial resolution and better measurement accuracy, it has become possible to perform crack detection and localization for concrete structures.
