Search

To study the mechanical property of concrete column confined by GFRP, we conducted 6 groups of specimens under axial compress. The influences of GFRP wind mode and layers were taken into account. According to the results, bearing capacity and ductility of the spiral winding specimen was improved greatly. The bearing capacity of the 6° spiral winding concrete column’s improvement is 28%, more than it of 0°. The fiber polymer’s utilization ratio can be improved greatly when column were combined with all spiral wind. Strengthen the concrete column of ±15°cross spiral winding pretend to be stronger capacity of bearing axial press than it of 6° spiral winding, but limiting strain tends to be lower. Shearing crack often happens at the 45°of the specimen, so shearing failure can be prevented effectively by GFRP (45°).Effective deformation and strength can be provided by FRP at the direction of axial and circular, and the reinforcing steel bar in concrete column can be substituted partially.

More attention has been paid on the technology of BFRP in civil engineering due to it’s unique properties, such as high strength-to-weight radio, good resistance to corrosion and convenient to construction. In order to study the properties of BFRP sheets confined concrete column ,we did it through three groups of columns subjected to axial loading tests and FEM analyses, mainly considering the effect of spacing of straps of BFRP sheets confining concrete column.The results shows that the axial compressive strength and ductility of concrete column winded by BFRP straps have all increased and the process of destruction of concrete column wrapped by BFRP is longer than that of the unconfined concrete column.

The carrying of Liquid hybrid bearing for ultra-high speed grinding is complex. The oil film temperature distribution in different input state is obtained through CFD analysis by FLUENT. On this basis, the temperature characteristics laws of the oil film with the input parameters change were obtained. Analysis shows that the relationships of oil film temperature with spindle speed and eccentricity are directly proportional and super linear, the relationship of oil film temperature with oil supply pressure is inverse ratio and the relationship with oil supply temperature is approximation directly proportional to the linear. Finally the significant of the various input parameters are analyzed through the orthogonal test. The results show that the effect of spindle speed is most significantly.

Analysis on the characters of ground subsidence of Yangjiaping mining area, with same excavation depth and recovery coefficient, the numerical simulations to nonlinear large deformation using finite-difference method(FLAC) are achieved on the different strip extraction schemes that adopted different mining and reservation width. The result indicates that the subsidence values and horizontal deformation increases with the increasing of the strip extraction width on condition of the same recovery rate. Based on probability density function (PDF) method, the relationship of the coal pillar width, the mining width and ground deformation is acquired, which is some useful reference for using the strip extraction method to control the surface movement and deformation.

The wedge splitting test specimens with three series of different relative crack length were used to study the influences of relative crack length on the fracture toughness of common concrete. The suitable formulation for fracture toughness of concrete with different relative crack length was gotten on comparing between fracture toughness test results and computation results of the model developed from Hu formula.