Advanced Materials Research Vol. 413

Abstract: In this paper, Based on collision simulation theory, a straddle-type monorail vehicle was considered as the research object. A collision model of Straddle-type monorail vehicle with human body model was set up. The course of collision between the straddle-type monorail vehicle and a rigid wall was simulated. During the body collision process, some parameters, such as velocity, displacement, energy and the injury of diver, were analyzed. According to the simulation results, the stiffness of vehicle and ability of energy absorption were evaluated.

Abstract: Orthogonal experiment design and variance analysis were adopted to investigate the hydrogen desorption properties of NaAlH₄ and LiAlH₄, which consisted of three stages, ball-milled under argon. Optimum milling condition was very important for the performance of NaAlH₄ and LiAlH₄, which was obtained from the orthogonal experiments. The orthogonal experiment design considered three experimental factors, i.e. weight ratio of ball to power, weight ratio of ɸ8 ball to ɸ4 ball and milling time, which varied on three different levels, respectively. According to the range analysis and variance analysis from the orthogonal experiments, the weight ratio of ball to powder and ɸ8 ball to ɸ4 ball had more impacts on the hydrogen desorption time of NaAlH₄,while the most sensitive influencing factor of LiAlH₄ was milling time. NaAlH₄ had the optimum performance when the weight ratio of ball to power was 30:1, the weight ratio of ɸ8 ball to ɸ4 ball was 0.5:1 and milling time was 0.5h. LiAlH₄ had the optimum performance when the weight ratio of ball to power was 40:1, the weight ratio of ɸ8 ball to ɸ4 ball was 0.5:1 and milling time was 2h.

Abstract: A simplified mechanical model in view of concrete component stability problem on fire was established. Assuming the temperature of fire and load as control variables, and material strain (or intensity) as state variables, destabilization mechanism of concrete component under high temperatures was carried out with the application of cusp catastrophic model. And the nonlinear mutation characteristics and failure mechanism of concrete component on fire were investigated. The results indicate that system's catastrophe characteristic is determined by fire duration, temperature, load capacity and load characteristics. When K=-F^'(u)/k_m>1, component destructs in the form of ductility failure, and when K<1, component destructs in the form of brittle failure. As the temperature rises, the caper value increases if the spring stiffness is defined.

Abstract: In order to optimize the material design for cement-fly ash stabilized crushed-stones, the strong interlocked coarse skeleton gradation was put forward based on the numerical experimentation method. In addition, the vibration method was employed to carry out the experimental study on the mechanical property of the cement-fly ash stabilized crushed-stones. Besides, the influencing regularities of the mixed amount of cement and fly ash on the cement-fly ash stabilized crushed-stones were researched. The result showed that the numerically simulated coarse aggregate gradation had great interlocked power, and the fine aggregate content of 31%±3% had stabilized mechanical property. Then, strong interlocked skeleton dense gradation of the cement-fly ash stabilized crushed-stones was put forward. Furthermore, when the 7d compression strength was used as the research indicator, the best proportion of the cement and fly ash was 1:0.5~1:1, and when the ultimate strength was used as the research indicator, then, the best ratio of the cement and fly ash was 1:1~1:1.5. Therefore, the cement dosage was advised to be 3~4% and the mixture amount of fly ash was 4~5%.

Abstract: For the PWR power plant in service, the lifetime of RPV is mainly determined by fast neutron (E>0.1MeV and E>1.0MeV) fluence. A new Low-Leakage Core Loading (LLCL) pattern is considered to prolong the lifetime of RPV to 60 years for Daya Bay nuclear power plant. Fast neutron (E>0.1MeV and E>1.0MeV) flux inserted to Reactor Pressure Vessel (RPV) under LLCL pattern is calculate by MCNP and compared with that under Long-Short Alternating Core Loading (LSACL) pattern. The results show that fast neutron fluence over inner surface of RPV under LLCL pattern decrease 28.50% (E>1.0MeV) and 28.22% (E>0.1MeV) compared with LSACL pattern and it is feasible expand the life of LWR-RPV to 60 years by LLCL pattern.

Abstract: The Stress Distribution in the Connection of the Spherical Shell and the Opening Nozzle Is Very Complex. Sharp-Angled Transition and Round Transition Are Used Respectively in the Connection in the Light of the Spherical Shell with the Small Opening and the Large One. the Influence of the Two Connecting Forms on Stress Distribution Is Analyzed by Establishing Finite Element Model and Solving it. the Result Shows there Is Obvious Stress Concentration in the Connection. Round Transition Can Reduce the Maximum Stress in Comparison with Sharp-Angled Transition in both Cases of the Small Opening and the Large Opening, Mainly Reducing the Bending Stress and the Peak Stress, but Not the Membrane Stress. the Effect of Round Transition on Reducing Stress Was Not Significant. so Sharp-Angled Transition Should Be Adopted in the Connection when a Finite Element Model Is Built for Simplification in the Future.

Abstract: In this paper, the rare earth cobaltite Nd_0.80Sr_0.20CoO₃ sample was prepared using conventional solid state reaction method. The dc magnetization, ac susceptibility, hysteresis loop of polycrystalline Nd_0.80Sr_0.20CoO₃ sample was carried out using the physical properties measurement system of Quantum Design. A dynamic analysis of ac susceptibility implies cluster glass transition temperature T_SG =72.06 K which occurs much higher by 25 K than that point at which the dc magnetization reaches a maximum. The cluster glass behavior of polycrystalline Nd_0.80Sr_0.20CoO₃ sample, which originates from the phase separation at low temperature, was systematically investigated in this paper. It was found that the sample has a small spontaneous magnetization and the weak frequency dependent peak so that we assume that the sample is cluster-glass.

Abstract: In this paper, a total of five structural insulated panel shear walls (SIPSW), in which with plywood facing and polystyrene foam board core, were tested under low cyclic horizontal loading. For the test specimens, different wall depth-width ratio and the opening sizes have been considered. The failure modes, failure mechanics, bearing capacity, lateral stiffness and ductility are discussed in detail. The test results showed that the hysteretic curve of SIPSW shows a reversed S-shape. Also the depth-to-width ratio and the opening dimensions of the shear walls have significant effects on load bearing capacity, ductility and elastic stiffness. What’s more, the performance of the SIPSW specimens was controlled by the fastener slip behavior of the SIP-to-spline connection, especially along the bottom spline. Finally, it is indicated that SIPSW have a good satisfaction upon seismic performance when used to timber structures.

Abstract: We have done experimental researches of study of impact of different fillers on physical, mechanical and tribological properties and found the optimal substance of fillers, which provides with best properties of polypropylene composite materials. We suggested the principle of construction of antifriction and antifriction-wear resistant polypropylene composite materials, which have high strength and tribological properties and used in cotton machines and mechanisms.

Abstract: We researched and developed effective polymer bitumen composites for hermetic of deformities seals of concrete and asphalts roads, bridges, aerodrome and airfields used in hot climate conditions and high lands.