Advanced Materials Research Vols. 291-294

Abstract: The energy method was used to analysis the flexural property of acrylate waterproof membrane in local loads during the period of construction and service. The membrane was formed by spraying-membrane waterproof technique for tunnel engineering. The maximum central deflection of the clamped circular plate was calculated in the uniformly distributed and concentrated loads. The minimum safety thickness was calculated in theory during the course of using. It was expected to provide theoretical reference for the further improving of spraying-membrane waterproof technique.

Abstract: This article describes an experimental setup to measure the TCC between interfaces of two contact solid materials. This apparatus consists of loading and load bearing subsystem, water-cooling subsystem, heating subsystem, temperature measurement and control subsystem and thermal insulation subsystem. A new kind of design scheme of the compensation heater is put forward. An experimental investigation of TCC is conducted with pressed pairs of TC4/30CrMnSi contacts in the range 40~140MPa. The results show that TCC over this condition increases with load, and is greater in the process of unloading than that of loading under the same condition.

Abstract: For the bending fatigue under the random load condition, the Miner cumulative fatigue theory was analyzed qualitatively. Random amplitude fatigue load spectrum for experiments was compiled according to that gears work under the load with Gaussian distribution load spectrum. Gear bending fatigue was carried out by the method of group test under the conditions of random load on the electro-hydraulic servo testing machine. Then the P-S-N curve of bend fatigue was got under Gaussian distribution load spectrum with particular coefficient of variation. Experiments prove that fatigue life from the result of random luffing amplitude fatigue experiments is lower than that from constant amplitude fatigue experiments, in which the upper limit of fatigue loads is the mean of load spectrum. It will be not reliable to estimate the bending fatigue life of gears that in the actual service.

Abstract: This study was focused on damage monitoring and estimation of 16Mn steel structures. This study used acoustic emission (AE) cusp catastrophe model to estimate the time at which the state of 16Mn steel will change from elastic deformation to yield deformation. Firstly, the tensile test of 16Mn steel plate specimens was monitored with acoustic emission technique. Secondly, a acoustic emission cusp catastrophe model was establish based on cusp catastrophe theory and acoustic emission signals. Finally, some catastrophe time was estimated with AE cusp catastrophe model. At this catastrophe time, the state of 16Mn steel plate specimen might change from elastic deformation to yield deformation. The experimental results show that AE cusp catastrophe model can estimate the time at which the state might change from elastic deformation to yield deformation of 16Mn steel in tensile test.

Abstract: To detect the delamination, disbond，inclusion defects of the glass fiber composite materials applied in the solid rocket motor, active infrared thermographic non-destructive testing(NDT) is researched. The samples including known defects are heated by pulsed high energy flash lamp. The surface temperature of the samples is monitored by infrared thermography camera. The results of the experiments show that the active infrared thermography technique is a fast and effective inspection method for detecting the defects of delamination, disbond，inclusion of the composites. The samples are also detected by underwater ultrasonic c-scans. The paper concludes that the active infrared thermography NDT is more suitable to rapidly detect the defect in large-area and the underwater ultrasonic c-scans is more suitable to quantitatively identify the defect in local-area.

Abstract: Absorber-microwave material Al-Si alloy powder was used as interlayer to join the 95-Al₂O₃ ceramics. The behaviors curves of time-temperature for Al-Si alloy interlayer and 95-Al₂O₃ ceramics at different microwave power were researched. The interlayer morphology of the joints region was characterized by SEM and the element and phase components were analyzed by EDX and XRD. The results indicated that the loact heating around 95-Al₂O₃ ceramics could be achieved by microwave sintering. The joint interfaces of Al-Si/95-Al₂O₃ formed at microwave 2KW/20min→0KW and the joint mechanism of 95-Al₂O₃ ceramics was transient liquid phase diffusion bond.

Abstract: In the paper, the experimental research on dephosphorization and iron yield for high-phosphorus oolitic hematite by coal-based carbothermal reduction was carried out. It indicated that microwave can speed up the rate of carbothermal reduction of iron ore and strengthen the effects of dephosphorization and increasing iron content. The dephosphorization rate and iron yield of high-phosphorus oolitic hematite exceeding 87.8% and 91.8% by the way of carbothermal reduction in the microwave field and a further fine-grinding and magnetic separation.

Abstract: The paper analyzes that hoop coefficients of the concrete-filled steel tube influence on dynamic response of the railway bridge height limit protective frame under impact load by using ANSYS/LS-DYNA. Change hoop coefficient of the concrete-filled steel tube structure by changing steel tube wall thickness. The result shows that with increase of steel tube wall thickness, the average impact force of protective frame will increase and the displacement and deformation will reduce, and protective frame can resist greater impact load. It will provide the reference for design of railway bridge height limit protective frame.

Abstract: There are many ways to increase the combustion rate of pulverized coal. In this paper, it is improve pulverized coal combustion rate by the method of microwave modification. In order to study the mechanism of modification on pulverized coal, microstructure and chemical compositions of pulverized coal before and after modification were studied. The results show that the microwave modification only changes the nature of PC itself without change component in the lower microwave power condition. And with the modified time extension, the pore number of PC surface gradually increases and the specific surface area enlarges. The highest combustion rate of modified-coal is 85.4%, and it is increase 11.1% than the raw coal in the experiment condition.

Abstract: Complex amino acid complexes of manganese ions were synthesized using the chelation technology under microwave irradiation. The influences of amount of water, reaction time, microwave power and the molar ration of complex amino acid and manganese on the yield of the synthesized compounds were investigated. Results suggest that optimal synthesis conditions are amount of water, 4 mL, irradiation time, 4 min, microwave power, 500 W, and the molar ration of reactant, 2:1, and the yield of the synthesized compounds was 67.42%.