Papers by Author: Li Zhang

Abstract: The Usu Bridge is single cable plane single tower cable-stayed bridge, the finite element program is used in this paper, the tensile、compression damage model of Concrete Materials is adopted, the damage of concrete structures of Usu main bridge under the combination of four kinds of static load is calculated, we get the damage distribution of the main tower and the main beam、the location of maximum damage and the effect of loading conditions, from which we find that the change of temperature has a greater impact on their damage and the role of the extreme wind has a greater impact on the main tower, thus we propose reasonable proposals on the construction and maintenance of the bridge.

Abstract: An interface crack problem in two nonhomogeneous plates under thermal loading is investigated. The interaction energy integral method (IEIM) is developed for obtaining the mixed-mode thermal stress intensity factors (TSIFs) of interface crack. The domain-independence of the present IEIM is verified. Numerical examples are presented and the results show good agreement with the analytic ones. Numerical results show that the method is very effective for the thermal interface crack of nonhomogeneous plate.

Abstract: A law on the cumulative damage is presented basing on total strain energy induced as damage parameter to calculate the cumulative damage when the specimens of concrete subjected to fatigue loading.Then the maximum of critical cumulative damage and location of production are determined basing on the equation of cumulative fatigue damage combined with experimental result through using the finite element analysis and the critical plane method in fatigue analysis.The relation equation between the standardized critical total strain energy density and stress level is obtained by considering the impact of loading level.The fatigue life of specimens can be predicted by combining the equation of cumulative fatigue damage with the relation equation of damage and stress level and the prediction results coincide with experimental results very well.

Abstract: A moving crack in a laminated structure with free boundary subjected to anti-plane shear loading is investigated in this paper. Using the bonding conditions of the interface between different media, all the quantities in our question have been represented with a single unknown function, and the problem is transformed into a dual integrated equation with the method of Fourier transform. The equation is solved using Schmidt method. Finally the numerical results show the relationships among the dynamic stress intensity factor and crack velocity, the height of different laminated material, shear moduli of different laminated material.

Abstract: In this paper, the behavior of a finite crack in an infinite plate of functionally graded materials (FGM) with free boundary subjected to SH-waves is considered. To make the analysis tractable, it is assumed that the material properties vary exponentially with the thickness direction and the problem is transformed into a dual integrated equation with the method of integral transform. The dynamic stress intensity factor is obtained using Schmidt method. The numerical examples are presented to demonstrate this numerical technique for SH-waves propagating in FGM plate. Finally the number of the waves, the gradient parameter of FGM and the angle of the incidence upon the dynamic stress intensity factor are also given.

Abstract: A fatigue crack growth model under constant amplitude loading based on the total plastic energy dissipation per cycle ahead of the crack was proposed. With the energy balance concept, the crack growth rate was correlated with the total plastic dissipation per cycle, and the total plastic dissipation per cycle was obtained through 2-D elastic–plastic finite element analysis of a stationary crack under constant amplitude. The predictions of the model were in good with the experimental results.