Applied Mechanics and Materials Vols. 488-489

Abstract: To improve the solubility of a kind of plant polysaccharide derivative (SJ) in drilling fluid system, it was modified by cationization with GTA as cationic etherifying agent. The reaction conditions were investigated by orthogonal designed experiments, and the optimized conditions were as follows: the mass ratio of GTA to SJ is 0.6g/1g with pH 12 at the temperature of 90°C. The viscosity of cationic SJ (CSJ) drilling fluid system was greatly improved and the temperature had a slight effect on rheological properties below 100°C. The inhibitive property of CSJ is evaluated by clay-swelling tests and the mud ball immersing tests, which is obviously stronger than SJ and even more effective than 4%wt KCl solution.

Abstract: With complex mechanics character and under the action of compression and tension in tri-direction, rock will show coupled plastic-damage mechanism as its basic character. Phenomenological coupled elastic-plastic-damage constitutive model with internal variable is proposed based on thermal mechanics theory, elastic law and macro damage mechanics. Numerical experiments on this model and analyze the model character. The result shows that the coupling model could realize rocks softening behavior brought about by damage and strength enlargement caused by confining pressure increasing.

Abstract: Since energy storage with phase change materials is an effective means of energy saving or conservation in buildings, its investigation and applications have received more and more during the recent years. The research actuality on energy saving of adjustment and control of building indoor temperature was summarized in this paper, and the two types of the major techniques with phase change material applied in adjustment and control of building indoor temperature was reviewed, in which one is the technique combined phase change material with building maintenance structure, the other is the technique to make phase change material applied to heating or air conditioning systems. The future research of phase change energy storage in adjustment and control of building indoor temperature was prospected.

Abstract: The high strength stainless steel wire mesh and high-performance mortar reinforcement has been gradually applied in construction, bridge reinforcement project. Study of the reinforcement at home and abroad mainly focus on research of strengthening RC beam shear, bending, and seismic performance. Although the application of RC column has already been carried out, there is also a short of basic technical an applied research for further study. After looking through a large amount of references, this article gives a summary of the present study about reinforcing RC column with the reinforcement, draws some conclusions and predicts the prospect of development.

Abstract: In response to the estimation of the peak values of wind pressure on the maintenance structure, the results with TTU low-rise building standard model of different methods are analyzed and compared. The results show: the results of peak-to-average method and Cook & Mayne method are very close for the long sample estimation of the peak values of wind pressure, the former is the most ideal method for estimation of extreme wind pressure; For short sample estimation, the peak-to-average method fails because the sampling is not long enough, but the Cook & Mayne method can estimate accurate peak value of wind pressure by the short sample (the corresponding prototype time not less than 600s); The peak factor method based on the assumption of normal distribution is not applicable to low-rise building and the results are relatively dangerous.

Abstract: For the small crack detection (crack ration less than 5%), the derivatives of mode shapes of cantilever beams were used for crack detection in the beams. These derivatives consist of the slope, curvature and rate of curvature, which are the first, second and third derivatives of the displacement mode shape respectively. The presence of a crack results in a slight change in the mode shape of a structure which is manifested as a small discontinuity in the response at the crack location. It is hard to detect small cracks in beams using the direct data of mode shape change. But when the first, second and third derivatives of the displacement mode shape, that is the slope, curvature and rate of curvature, respectively, of the cracked cantilever beam provide a progressively better indication of the presence of a crack. However, `noise' effects due to the difference approximation error also begin to be magnified at higher derivatives so that it is not advantageous to go beyond the third derivatives of mode shapes. For the intact beam, these derivatives are smooth curves. So the local peaks or discontinuity on the slope, curvature and rate of curvature modal curves can be used to indicate abnormal mode shape changes at those positions. In this way, these local peak positions can be used to detect and locate cracks in the structure. The modal responses of the damaged and intact cantilever beams used were computed using the finite element method.

Abstract: In the process of construction, with the mixture ratio design and appropriate construction conditions of SAC asphalt concrete mixture, it can not only have dense gradation with typeIasphalt concrete which has good durability and small porosity with its skeleton dense structure, but also it can be compatible with typeIIasphalt concrete which has the ability to resist deformation and the depth of the surface structure. This paper is making an effective exploration on the construction technology and the mixing ratio design of SAC asphalt concrete with the aid of the authors construction test results of a certain highway construction.

Abstract: The electric power network reconfiguration of warship integrated power system is one of the most important methods to restore power supply and improve survivability of shipboards under fault. The reconfiguration method based on graph trace analysis (GTA) and generic algorithms is proposed for warship integrated power system in order to maximize the number of served loads with highest priority under fault. Simulation results have demonstrated that is method is able to reach target configurations.

Abstract: For the failures of a 30MW tubular hydro-generator such as no-load voltage waveform is bad, damper bars are over heat, a multi-slice moving electromagnetic field-circuit coupling FE model of tubular hydro-generator and a 3D temperature field FE model of the rotor are built respectively.And the computations about the failure reasons and the optimized design schemes are implemented and analyzed by these modles.And the calculation results are coincident well with the test data.

Abstract: In order to analyze the influence of tubular hydro-generator no-load voltage waveform by the rotor skew, the multi-slice moving electromagnetic field-circuit coupling model of a 36MW tubular hydro-generator is established, then the no-load voltage waveforms of the design scheme which skew rotor is calculated.