Influence of masonry RC wall composite structures’ stiffness feature extraction and small sample learning

According to the stress characteristics of masonry RC wall composite structures, the paper puts forward the calculation formula of the optimal number of RC walls under the action of earthquake. In the formula, the main influence factors of parameter of amount of RC walls are: the characteristic site period,the seismic fortification intensity,the elastic allowable deformation value, the stiffness characteristic coefficient of composite structures, the compensation coefficient of the non bearing walls on natural period of vibration,etc. According to the main influence factor, the stiffness characteristic coefficient λ, this study gets the value tables of parameter of amount of RC walls in the calculation formula of the optimal quantity of concrete wall under various anti earthquake grades,ground categories and design groups. A numerical example shows this method is simple and practical.It can be used for the initial design stage of this kind of composite structures in seismic regions.     

Bearing Capacity of Top-coal Body and Working Resistances for Supports in Coal Faces with Sublevel Caving

The calculation on working resistances of supports has been one of key research questions for coal faces with sublevel caving. Based on experimental results of mechanical property of top-coal, it is the top-coal failure strength meeting Mohr-Coulomb Theory that is summed up. According to force characteristic of top-coal body in coal face with sublevel caving, using strain-equivalent principle of Damage Mechanics, the authors set up bearing mechanical model for top-coal body within face width. From the top-coal bearing capacity point of view, the interaction relationship between supports and top-coal body is studied. Theoretical calculation formula on working resistance of supports is deduced. Ground press behaviors which working with resistances of supports are increased with top-coal strength increment were better explained with this model. The conclusions have a definite direction value for calculating working resistances of supports in coal faces with sublevel caving.     

Research on the influence of structure integral performance to the RC frame structure failure mode(Ⅰ): Numerical analysis

Three models of 3D cast-in-place RC frame structures are simulated in ABAQUS. In the three models, one represents the actual RC frame structure with monolithic slab, one represents the open frame structure used in structural design currently, which means truss structure at the stage of calculating internal forces of frame beams and columns, and the third one represents the open frame structure which takes into account some slab reinforcement in the rectangle section of frame beam to consider the slab participation in the flexural capacity of frame beam. By investigating the failure mode of these three models, the development of plastic hinges, the reinforcement stress of beam, column and slab in the models, the influence of monolithic slab to the bending resistance of beam end is studied. It shows that the existence of slab makes the failure mode of actual RC frame structure different from the design criteria of strong column weak beam. It also indicates that the slab participation in the bending resistance of beam end is not only expressed in the slab reinforcement but also in the structure integral performance. Besides, when using the effective flange width to consider the slab reinforcement participation, the structure integral performance, lateral displacement and other relevant factors should be taken into account.     

Numerical simulation and experimental analysis for process parameters of cold straightener

This paper focuses on the design of eleven rollers straightener. An elastic plastic FEM model is introduced to cope with the difficulty of pre estimating the performance of straightening during the design process. To obtain straightening force, stress, strain, elastic plastic ratio, relations between reduction amount of roller and roughness of plate per square meter, a three dimensional element model is established and straightening process is simulated. In addition, an experiment is conducted to measure the reduction amount of roller and the roughness of plate per square meter. It is shown that the results of numerical simulation are consistent with the experimental results. The developed computing model can provide essential references for the optimization of straightener.