Applied Mechanics and Materials Vols. 166-169

Abstract: The key components of space steel frame structures which included 1-5 story respectively were judged by using energy method. It was shown in the results that besides interior and corner columns, adjacent side columns in low buildings should be paid attention to in analyzing progressive collapse. The approach of utilizing story as weight to modify importance factor of space frame structure was also proposed, and the modified importance factor complied better with collapse resistant characteristics of real buildings.

Abstract: Accordingly to the problem that during the fault diagnosis of the flap system, the existing experience and knowledge are always uncertainty, inconsistency, incompleteness, what’s more, the different fault cause has different effect on the fault. So the Weighted Fuzzy Petri Net is adopted, and fuzzy Petri net and matrix operations are combined, then the formal process of fuzzy inference reasoning algorithm is researched in order to obtain the fault probability of each event in the fault tree of flap system. The presented method effectively makes up the deficiency of the traditional FTA and FMEA, and provides a new fault diagnosis method for complex systems, so the fault diagnosis method based on Weighted Fuzzy Petri Net has a great practical value.

Abstract: Based on the finite-element vibration equations of viscoelastic beam in Laplace domain and the corresponding analytical solution, a semi-analytical frequency equation, which contains the complex modulus of the viscoelastic material, is derived. With several simple measuring instruments, the vibration parameters of the viscoelastic beams can be measured. According to the semi-analytical frequency equation, the complex modulus of the viscoelastic material can be calculated by a nonlinear programming algorithm. As an illustrative example, the vibration test of free-free beams made of viscoelastic expoxy composite material is presented. A five-parameter complex modulus is assumed and evaluated.

Abstract: Decomposing furnace, Temperature forecasting, Grey system theory

Abstract: Open caisson is one of the common used structures, as a working shaft in pipe jacking project. Disturbance of the soil behind the reaction wall of open caisson (SBRWOC) will reduce the efficiency of jacking, and affect safety of site operation and control. However, there are few studies on disturbance of SBRWOC. In this paper, combining the project of parallel pipe jacking passing under the Guan River in Jiangsu Province, China, field monitoring of SBRWOC is carried out during pipe jacking construction, including earth pressure and lateral displacement of SBRWOC. The maximum lateral displacement of SBRWOC is about 27 mm and the maximum earth pressure is 98.5 kPa. These results are useful for engineers to study disturbance characteristics of SBRWOC and reduce environmental impacts during pipe jacking construction.

Abstract: Based on the easy testability and high measure precision of structural frequency, a damage identification method for shear buildings is presented. With frequency being regarded as the function of damage parameters, the linear equations with damage parameters as unknowns can be constructed via Taylor expansion. The equations are solved to locate the whole damage location and quantify the severity of the damage. Furthermore, the iteration-self modification is proposed to improve the accuracy of damage identification greatly. The data used in the method include frequency before and after damage. A numerical simulation example using a three-storey sheer structure is given to validate the present method.

Abstract: The dynamic response and failure mode of light-weight steel columns under blast loads were studied in this paper by using nonlinear finite element analysis (FEA) software ANSYS/ LS-DYNA, aiming to develop the degree and modes of the excessive plastic deformation during failures of the columns under diverse parameters. The damaged columns with initial blast-induced deformation may evidently influence vertical stability of light-weight steel frame structures. During the numerical simulation, the element of three dimensional solid SOLID164 was used, and the strain rate effect on material strength was included in the material model with Plastic-Kinematic (MAT-03). The main parameters included in the analysis were boundary conditions, scaled distances of explosions, and the vertical compressive load ratios applied on tops of the columns. The results showed that the column with both two fixed ends was the most beneficial to resist blast shock wave, the horizontal displacement at the middle span of the columns were obviously decreasing as increasing of the scaled distances of the explosion, and the axial compression ratio only significantly influenced the column with a sliding end. The failure modes of the developed columns may be summarized as bending failure, direct shear failure, and bending shear combination failure.

Abstract: To study a meteorological tower structure response under the lateral loads, the paper established a meteorological tower of reinforced concrete shell finite element model, By analyzing of the structure to get the structure and formation quality modal participation factor, and the structure of the wind load And the response under earthquake were analyzed by the structure of the base shear, overturning moment floors, floor displacements and story drift response.

Abstract: Based on the flexural experiments of 10 SRHSHPC (steel reinforced high strength high performance concrete) simply supported beam specimens, the destructive process and modes were observed, analyzed its flexural failure modes and mechanisms, and investigated the influencing factor for the flexural behavior of beam, such as concrete strength, steel ratio, flange width ratio (the ratio of steel flange width to beam width) and shear connections. Finally, a formula which was suited for the flexural capacity of cross section of SRHSHPC beam was established. Research result will provide a theoretical basis for the establishment of related calculation theory and engineering application of SRHSHPC beam.

Abstract: Based on the general finite element software ABAQUS, the FE model of 30-story SRC frame-RC core wall hybrid structure is established and the simulation analysis is conducted to the evolution of storey damage under cyclic loading, then the law of storey damage evolution affected by component damage is revealed. The analysis results show that the storey damage evolution is affected more by the damage of SRC column and RC shear wall than by the SRC beam's, when the single component has similar damage; and also is affected greatly by the damage of RC shear wall, when the two different types of components have similar damage. Based on the results of numerical simulation, the mathematical relations between the component damage and the storey damage are established, which would provide theoretical support to the hybrid structure damage model under earthquake excitation.