Advanced Materials Research Vols. 217-218

Abstract: Based on the finite element theory, air compressor plate drum is analyzed in the rotating and loading circumstances. The maximum displacement sum was regarded as a random output variable, when plate angular velocity the elastic modulus, Poisson’s ratio density and equivalent centrifugal force were randomized, and were considered as a random input variable. Supposed all input variables are normal distribution. After Monto Carlo sampling is implemented one thousand times, the reliability and sensitivity of air compressor plate drum can be obtained.

Abstract: In shaft coupling, based on the finite element theory, stress distribution in shaft coupling can be obtained. After the shaft coupling is carried on the modal analysis, fifth-order inherent frequency from first-order to fifth-order can be calculated out. After modal of shaft coupling can be expanded, relative displacement vector sum and relative Von Mises stress mode of shaft coupling from first-order to fifth-order can be obtained.

Abstract: The effect of electromagnetic field and iron content on the solidification structure of copper-iron alloys had been investigated in this paper. The results show that the addition of iron to copper causes considerable grain refinement, and the refinement increases with the iron content. Applying electromagnetic field during the solidification of Cu-Fe alloys can further refine grain of hepoperitectic alloys, but has no obvious effect on the grain size of heperperitectic alloys. Primary γ-Fe dendrites are gradually broken and scattered uniformly throughout the matrix under the influence of electromagnetic field. When the current intensity is 200A, the primary γ-Fe appears as fine petal shape distributed uniformly over the matrix.

Abstract: Poly vinyl pyrrolidone (PVP(K30)) / Bisphenol A Dicyanate ester (BADCy) blends were fabricated to increase the toughness of BADCy by blending processing in this paper. Curing parameters were determined by gelation time curves and differential scanning calorimetry (DSC) of the systems. Fourier transform infrared spectrometry (FTIR) and DSC data were employed to show the curing behavior and kinetics of the systems. Mechanical properties of the cured resin had been improved rapidly with the increasing of PVP(K30) at low mass fraction, but would decrease when mass fractions of PVP(K30) were higher than 15%. Scanning electron micrograph (SEM) was applied to show the microstructures of the cured matrixes. Based on the thermogravimetric analysis (TGA) curves, water absorption curves, SEM images and dielectric properties of the blends, it can be concluded that the addition of PVP(K30) can improve the toughness of BADCy greatly with little loss of other properties.

Abstract: Six specimens of interior joints with different depth beams were tested under reversed cyclic loading. The failure characteristics and shear force versus shear angle skeleton curves of interior joints are analyzed. Based on the experimental study, an analytical model for equivalent joint core of abnormal joint under the combined action of axial load and shear is established, and the shear stress versus shear angle curves of equivalent joint core of tested specimens was calculated by using modified compression field theory (MCFT).Test results indicated that the first crack appeared in the minor core (determined by the low beam and the top column), and the final failure appeared in the large core (determined by the high beam and the bottom column). The critical crack load was quite nearly with the ultimate load of abnormal joints, and seismic behavior of beam-column joint sub-assemblage was poorer than that of ordinary joints. Good agreement between experimental results and prediction results is achieved.

Abstract: Two-dimensional transient heat transfer model of the plug of regenerative cooling plug nozzle is built. Based on the convective heat-transfer coefficient and the radiation heat flux obtained using analytic method and axisymmetric unstructured Delaunay grid applied to mesh the simplified physical model, numerical simulations of transient temperature field and thermal distortion are carried out by finite element method combined with thermal-structure coupling theory. Not only the results of numerical calculation under working conditions with and without regenerative cooling, but the results under low and high working conditions are compared. The results shows that thermal distortion can be reduced effectively when regenerative cooling method is adopted in the throat and combustion chamber that have the most serious thermal condition.

Abstract: As one of the most important economic crops, tobacco is often endangered by pest disaster, which can lower the quality and output of tobacco, traditional methods can’t forecast pest disaster in time for the quantity of tobacco. This article analyzes the theory of remote sensing monitor and comes up to monitor tobacco diseases with remote sensing. It discusses the feasibility of using this technique in this article by introducing the basic theory of RS and monitoring other pest disaster.

Abstract: The creep test of the No. 3 coal seam of Daizhuang Coal Mine is carried. Based on the experiment results, the creep support effect of deep pillar is analyzed with LS-DYNA. The results show that the circumferential initial creep stress of the tested coal is 3.061MPa and the circumferential initial creep stress is far below the axial initial creep stress which is 7.020MPa. In addition, the creep strength is 9.3266MPa and the creep coefficient is 0.6472. According to the test results, the creep support effect of deep strip pillar can be simulated excellently with LS-DYNA. Stress and deformation in simulated strip pillar show evident rheology. Many changes will take place in the stable situation of pillar after the working face mining. Under the effect of the overlying strata, this pillar turns into steady creep state after 15~16 months, then the pillar is able to maintain long-term stable state.

Abstract: A laboratory equipped with the thermal energy storage unit utilizing the solar heat sources was designed and constructed. The spherical capsules which were filled with the phase change material (PCM) were installed inside the unit. The temperatures at inlet and outlet of the thermal energy storage (TES) unit and at the first through seventh layers of heat transfer fluid (HTF) were measured. Many groups of experimental schemes were designed to evaluate the storage unit’s performance. The effects of inlet fluid temperature and flow rate of HTF on the performance of the storage unit were analyzed. The experimental results showed that, with the inlet temperature and flow rate of HTF increasing, the time required to complete the charge process reduced constantly; the efficiency of thermal energy storage is consequently improved. The results provide the basis for designing, optimizing, and applying the TES unit.

Abstract: The thermal fatigue fracture of engine exhaust manifold will affect its service life and engine work, to prevent and resolve this problem, finite element analysis software ANSYS was used to establish a finite element model for exhaust manifold work environment, and calculate the steady-state temperature distribution under the thermal field. Through the thermal stress analysis of manifold, identified the region most prone to the generate thermal stress and fracture, conducted failure analysis, for the existing problems analyzed the reason of thermal fatigue fracture on exhaust manifold, and provided a reliable basis for the optimization of the exhaust manifold. The thermal fatigue failure of exhaust manifold got good improvement after the structure improvement.