This paper deals with the roller chain commonly used for transmission of mechanical power on many kinds of industrial machinery, including conveyors, cars, motorcycles, bicycles, and so forth. It consists of a series of four components called a pin, a bush, a plate, and a roller, which are driven by a sprocket. To clarify the fatigue damage, in this paper, the finite element method (FEM) is applied to those components under three different types of states, that is, the press-fitting state, the static tensile state, and the sprocket-engaging state. By comparing those states, the stress amplitude and the average stress of each component are calculated and plotted on the fatigue limit diagram. The effect of the plastic zone on the fatigue strength is also discussed. The results show that the fatigue crack initiation may start around the middle inner surface of the bush. As am example, the FEM results show that the fatigue crack of the inner plate may start from a certain point at the hole edge. The results agree with the actual fractured position in roller chains used in industry.

Reinforced concrete ribbed arch bridges are applied widely in China, especially in mountain areas of southwest China. After many years of operation, some distresses and damages occur of this kind of bridges. There are 100 bridges of this style are generally surveyed and 49 of them with typical distresses are investigated in details on site. Based on it, characteristics and rules of distresses are classified and summed up, and the reasons of them occurrence are analyzed. This process is expected to provide reference and evidence for design, construction, maintenance and strengthening of this kind of bridges, and establish a foundation for further research.

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The externally prestressed bridge finite element analysis module redeveloped based on ANSYS software is introduced，realizing finite element analysis method for externally prestressed concrete bridge. It is able to build the externally prestressed bridge finite element model, combined with Solid65 and Solid45 simulated concrete, and Link8 or Link10 simulated prestressed tendon. It is also able to bring material and geometric nonlinear effects into the analysis, for analyzing ultimate bearing capacity and local stress characterization of the externally prestressed structure. A bridge model is generated as an example for verifying the application of the module. Based on it, the model then is equipped with different allocation arrangements of internal and external tendons to analyze the mechanical characteristics of externally prestressed concrete bridge. Research is conducted for the effect on ultimate bearing capacity by allocation arrangement of tendons, and providing design suggestion and theoretic basis.

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