Advanced Materials Research Vol. 619

Abstract: Vertical seism has the same damage to the structure as the horizontal earthquake did. But vertical seism has not been taken seriously as it should be because its acceleration is smaller than that of horizontal earthquake. This paper describes the characteristics of vertical seism and a kind of vertical isolation device is designed based on the application of pulsating hydraulic theory. Moreover, it also states theoretical analysis and experimental study about properties of the device.

Abstract: In order to study the platform lorry’s travel and drive system, based on the prototype of real platform lorry，the system was properly simplified in engineering application under the circumstance of fully satisfication for control strategy. A method of test-bench contruction based on three variables of engine, pump and motor was provided, furthermore, detailed analysis and calculation for the selection and matching of system major parts was carried out, and the test-bench of the platform lorry’s travel and drive system was established. The test-bench mentioned above could also be used for the hydraulic system laboratory research of platform lorry or other similar models.

Abstract: In order to satisfy the practical requirement, Durability test-bed for new developed hydraulic pump is designed which mainly includes design of hydraulic systems, design of data acquisition and processing system and design of test bench and electronic control system. According to application, it shows that the Durability test-bed is effective for durability test of new developed hydraulic pump and it can help to improve the design of hydraulic pump

Abstract: In order to improve the power performance and fuel economy performance of powered platform lorry, this paper analyses the characteristics of hydraulic system and engine to make three-close-loop control strategy. Its physical model is built with AMESim simulation software and the three-close-loop control strategy controller for the system is constructed in Matlab/Simulink environment. To evaluate the three close-loop control strategy, a co-simulation method with AMESim/Simulink is used. The simulation results show the control strategy is effective to improve the efficiency of the hydraulic drive system, the utilization of engine power, and the life of hydraulic components.

Abstract: The high temperature self-lubrication Ni-Cr-W matrix composites were prepared by powder metallurgy and sintered by hot isostatic pressing (HIP). Atomized Ni-Cr-W powder was mixed with friction components of MoS₂ and Graphite. The mixed powders were cold pressed 450MPa and sintered at 1100°C~1200°C in the presence of argon atmosphere for 1 hour under 180MPa hot isostatic pressing with respect to their application in slide bearing bushing. The tribological properties are investigated on UMT-2 tester in ball-on-disc against alloy steel ball. The results showed that the appropriate addition of MoS₂ show excellent antifriction and wear resistance. And the friction coefficients and wear rates decrease over the wide temperature range of 25°C~600°C compared that of the composites by pressureless sintered method. The results indicated that HIP technology had an obviously strengthening effect on the density, and anti-press strength.

Abstract: Nb_1-xTi_xSe₂ (x=0～1) micro/nano-particles have been successfully prepared via solid-state thermal (750°C) reaction between microsized Nb, Ti with Se powders under seal environment in a seal quartz tube and characterization by X-ray diffractometer and scanning electron microscopy. It was found that the morphologies of the as-prepared products changed from microplates to micro-nanoparticles or aggregations composed of layer structure with the doping of Ti. And the amount of regular hexagonal microplates evidently reduced and nanoscaled particles increased with the increase of the contents of Ti dopant within a certain limit (1-20 atwt. %). The tribological properties of the as-prepared products as additives in paraffin were investigated by UMT-2 multispecimen tribotester. By the addition of Nb_1-xTi_xSe₂ micro/nanoparticles in paraffin, the antiwear ability was improved and the friction coefficient was decreased. The paraffin with Nb_1-xTi_xSe₂ micro/nanoparticles showed better tribological properties than that with pure NbSe2. A combination of the molecule-bearing mechanism of sliding friction, and fill in-repair work between the rubbing surfaces can explain the good friction and wear properties of Nb_1-xTi_xSe₂ micro/nanoparticles.

Abstract: The main mechanical properties of line fitting steel under low temperature is different from that under normal temperature．the experiments of line fitting steel(Q345R)under low temperature and the Variation of the mechanical properties (yielding strength、ultimate strength、elongation)with temperature is showed in the paper．

Abstract: A novel kind of block polymer with characteristics of rod-like chain conformations-water-borne polyurethane (PUA) was synthesized by incorporate polyacrylate (PA) into the PU chain to prepare an aqueous polyurethane-polyacrylate (PUA) hybrid emulsion with core-shell structure. The interactions between Water-borne PUA and C-S-H nanostructure, which include intercalation and the polymerization degree of C-S-H silicate chains, were studied by small angle X-ray diffraction spectra and 29Si NMR spectra, respectly. The influences of water-borne PUA on mechanical performance of C-S-H were investigated experimentally. The small XRD results show that no evidence is observed for any fundamental size change in the C-S-H particles that have been formed in the presence of polymer. The NMR results indicate that there is a significant increase in the Q2/Q1 ratio ranging from 0.5 for pure C-S-H to 2.2 for PUA-C-S-H, respectively. The degree of silicate polymerization increases from 3.0 for pure C-S-H to 6.4 for PUA-C-S-H by calculation. PUA had minimal harmful effect on the compressive strength whereas the flexural strength was increased by 23.2% with dosage of 0.5% and 23.3% with dosage of 1.0%, respectively.The fracture energy ratios of concrete with a dosage of PUA less than 1% are greatly improved more than double with the decreasing of concrete strength less than 10%. The water-borne PUA also enhances the impact resistance of concrete. The impact energy consumption of samples with PUA increase nearly three times more than reference samples, also better than samples with PP fiber.

Abstract: Mg2Si particle reinforced hypereutectic Al-Si composite was prepared by casting, and the microstructure and wear resistance of the composite were researched. The results indicated that the morphology of Mg2Si obviously changed with Mg2Si contents increasing, in which the morphology of Mg2Si in the composite had changed from polygon block to characters like and finally became coarse dendrite. There were effects of Mg2Si content and morphology on the wear resistance in the composite, which had the higher hardness and better wear resistance at the suitable Mg2Si content.

Abstract: This article simulation studies the thermal Characteristics of a lower temperature phase change materials (PCMs) using in the building energy storage by two different models. In the process of phase change, liquid phase is used as two ways of heat exchange: pure heat conduction and natural convection, and we exploit CFD software to carry out numerical simulation. To compare and analyze under melt and solidification, the proportion of solid and liquid, the time of phase change, the interface of phase change and motion temperature image of liquid-region.