Applied Mechanics and Materials Vol. 621

Abstract: It is significant theoretically to study the nucleation laws of the phase transformation products of the supercooled austenite. The different iron and steel materials were used to study the nucleation of pearlite, bainite and martensite by QUANTA-400 environmental scanning electron microscope and JEM-2100 transmission electron microscope. The results show that, from the high-temperature zone to the low-temperature zone, the nucleation of the transformation products of the supercooled austenite is a gradually evolutionary process from two-phase nucleation to single-phase nucleation. Pearlite nucleates in the austenitic grain boundary, bainite nucleates preferentially in the grain boundary and sometimes in the grain interior and martensite nucleates preferentially in the interface and generally in the grain interior. The preferential nucleation sites are the interface, and with the decrease of the transformation temperature, they gradually shift to the defects in the grain interiors, which accord with the general rules of the phase transformation nucleation.

Abstract: In this thesis we provide the electrodeposition technology by means of monolayer templates for fabricating regularly hexagonal array of copper surface, predict the wetting transformation in theory. We report the result that original hydrophilic copper surface may turn to be hydrophobic surface by this kind of structurization. The apparent contact angle would convert from less thanto more than.

Abstract: Introduces a kind of self-insulation board made of waste foam glass, fly ash, and FGD gypsum as main raw material. And researches on the preparation and performance of the insulation board, such as strength, thermal conductivity and water absorption per volume.The test shows that the thermal conductivity is between 0.07-0.13 w/(m·k), strength can reach more than 0.5Mpa,the minimum dry density is 400kg/m³.

Abstract: We dominated localized surface plasmon resonance (LSPR) of aluminum (Al) by controlling their size and density. We report the implementation of Al nanoparticles (NPs) fabricated on the surface of the Ta₂O₅ layer on glass for localized surface plasmon resonances (LSPRs) coupling. The size, density controllable small Al NPs were fabricated using oblique angle deposition method. The optical properties of the NPs array were studied by UV spectrophotometer and finite-difference time-domain (FDTD) simulations. We found that the LSP resonance wavelength of different sizes of Al NPs array exists a blue shift in the extinction spectrum as the particle size decreases.

Abstract: The experimental investigation of structure formation processes in preliminary mechanically activated powder mixture 3Ti + Al was carried out. The synthesis was realized in the thermal explosion mode with the use of high-frequency induction heating. The characteristic features of structure and phase formation in this system by quenching of the mixture at different annealing times were installed. It was shown, that the processes of structure-phase formation occur in the following sequence: chemical reaction - structural relaxation - thermal relaxation - thermal equilibrium. The time-temperature intervals of Ti₃Al strictly single-phase compound existence with various concentrationsof non-equilibrium defects of the structure were established.

Abstract: Series samples ZnS and ZnS: Cu²⁺(0.001<x<0.05) have been prepared by a simple and template-free microemulsion improvement method. From the XRD we know that all samples are single phase. The SEM photo shows that the particle sizes are about 20nm~50nm.When the contents of doping Cu²⁺ ions increasing, the particle sizes become larger, which proves that Cu²⁺ ions occupy the position of Zn²⁺ ions. The emission spectrum (ES) indicates that when doping Cu²⁺ ions ,samples show a blue light and the main emission peaks which caused by Cu²⁺ ions t² transition locates at 425nm.

Abstract: In this paper, a nondestructive technique is used as a tool to control cracks and microcracks in materials. A simulation by a numerical approach such as the finite element method is employed to detect cracks and eventually; to study their propagation using a crucial parameter such as the stress intensity factor. This approach has been used in the aircraft industry to control cracks. Besides, it makes it possible to highlight the defects of parts while preserving the integrity of the controlled products. On the other side, it is proven that the reliability of the control of defects gives convincing results for the improvement of the quality and the safety of the material .

Abstract: This subgrade is a large number of backfill soil and gravel pile foundation. The building produce settlement because of bearing capacity of foundation soil is poor. The rapid settlement of the building has been stopped using grouting techniques but the effect may not be quick; For the purpose of settlement resistance and deviation rectification, it is better to use a comprehensive treatment methods which combine the hollow grouting anchor static pressure pile, heaping load and drawing out soil with watering. It acquire a good effect of settlement resistance and deviation rectification. By establishing finite element model of the frame structure of the building using software of ANSYS, the housing stress and deformation in the process of rectification can be simulated and compare with the data of field. It can confrim a dependable construction schedule and insure the housing stress and deformation is in the range of safety.

Abstract: The methodology of the fatigue load and the bearing life estimation for the ball bearings is presented in the paper. The proposed algorithm is based on the elliptical contact solution and the application of the multi-axial high-cycle fatigue criterion. As the example the radial 6204* and thrust 51104 ball bearings are investigated (SKF). The maximal fatigue loadings are calculated for different geometry (race conformity ratio) and the bearing life of the bearings. The proposed model is also verified with use of the finite element calculations.

Abstract: Contrary to other structural types, unreinforced masonry buildings display local collapses during strong earthquakes, especially in the case of large-hall constructions. This is also what has happened in the Oratory of San Giuseppe dei Minimi, located in the historical centre of L'Aquila (central Italy) and affected by the 2009 earthquake. The church suffered the out-of-plane response of its façade and parapet belfry. These mechanisms are studied recurring to non-linear dynamic models, calibrated with experimental data. The outcome of such analyses is in reasonable agreement with observed damages. Hence, it is possible to recommend this approach for the seismic assessment of similar buildings.