Advanced Materials Research Vols. 311-313

Abstract: Cement based composite cementitious material containing steel slag used in road has been prepared to deal with the current situation that the transportation carbon emission increased year by year. In this material, 40% cement has been replaced by equivalent steel slag, which has the ability of CO₂ sequestration. This paper studied the CO₂ sequestration effect and the mechanical properties of the pure cement, the pure steel slag, and the cement based composite cementitious materials containing steel slag. It has been shown that the cement based composite cementitious materials containing steel slag have excellent CO₂ sequestration property. The mass fraction growth rate of carbon reached 10.86% after 1 hour carbonation experiment, the value between which of pure cement and pure steel slag, and the compressive strength of the composite cementitious materials at 28-day age can reach 45.3MPa, meeting the requirements of road.

Abstract: To choose the suitable heat insulating material for refrigerated cargo hold shipboard of fishing vessel, a steady state three-dimensional mathematical model of heat transfer is developed in this paper. The heat-transfer model is simplified reasonably in order to facilitate analyzing and solving. After defining the boundary conditions of the model according to the heat-transfer process of the shipboard, numerical simulations with different heat insulating material are performed using computational fluid dynamics (CFD) software PHOENICS. The obtained temperature distributions of the model in each case are analyzed. The suitable one is pointed out according to the degree of influence of the heat insulating material on heat-transfer property of the shipboard.

Abstract: We had investigated the electromechanical coupling coefficient (K²) of surface acoustic wave (SAW) on proton-exchanged (PE) and annealed PE (APE) z-cut LiNbO₃ waveguides using octanoic acid. The penetration depth of hydrogen assumed to be equal to the waveguide depth (d) was measured by secondary-ion mass spectrometry (SIMS). The frequency response of SAW was measured with a network analyzer. The annealing process was carried out in a horizontal furnace kept at 400°C for 2 h under a dry O₂ gas flow. The change of K² in PE and APE samples fabricated under different conditions was dependent on kd, where k was the wavenumber. The experimental results showed that the variation of K² in PE samples was significantly decreased with the increase of kd. The reduction of K² may be due to the reduced piezoelectric coefficients in the PE layer. On the other hand, the variation of K² in APE samples also exhibited the decreased tendency after annealing. It indicated that the annealing process could not restore the reduction of K² caused by the PE process.

Abstract: Embedded and co-cured composite damping structure is a novel damping processing structure, which possesses excellent damping properties and mechanical performances. In this paper, explicit dynamic analysis software LS-DYNA is employed to simulate low velocity impact on embedded co-cured composite damping structure panels. To illustrate the validity of modeling and calculation method, the simulation results are compared with the experimental data. And the results show that the impact resistance of embedded co-cured composite damping structure is much better than composite panel without damping material.

Abstract: Microstructure formation under the applied strain for the alloys with different shear modulus and anisotropy were studied using the phase-field simulation. The uniaxial morphology depends on the magnitude of applied strain, the ratio of shear modulus and ratio of anisotropy between the precipitates and matrix. However, the morphology orientation depends not only on the sign and direction of applied strain, but also on the ratio of anisotropy and the ratio of shear modulus between the precipitates and matrix. The simulation results are helpful for the materials microstructure design and control by the combination of internal elastic stress and the applied strain.

Abstract: In Reconfigurable machine tools (RMTs), the reconfiguration only occurs at the mechanical interface system composed of mechanical modules, joining mechanisms, or adapter mechanisms, and their reconfigurability degree depends strongly on the properties of its module interfaces. This paper investigates the performance criteria influencing the reconfigurability of module joint interfaces. An Extenics Element Model (EEM) method is proposed to model the component module of RMTs, module interfaces and the relationship between mechanical modules. Furthermore, the evaluation values are determined based on the Simple Dependent Function (SDF) to evaluate the reconfigurability of different joint interfaces. Finally, two types of joint interfaces between worktable and slide are presented to verify the proposed model and evaluation approaches.

Abstract: Due to the limitations of dimension and experiment cost, the reliability analysis of PSSS (Periodic Symmetric Struts Support ) mainly depend on reliability simulation. Inlet temperature, inlet velocity and inlet pressure of the thermal channel are the major random variables impacting PASS. In this paper, it generates 120 groups random variables by using stochastic finite element method ,which combined finite element software and Monte Carlo method. Temperature distribution is obtained based on fluid-structure interaction analysis with each group of variables as boundary condition, then thermal stress distribution is obtained by using steady state thermal analysis. After that, the maximum stress value of each group are extracted out, and the curve fitting for the probabilistic distribution curve of the stress was carried on. Then the function of the probabilistic distribution of maximum stress was got. According to the stress - strength interference model, the reliability calculation of PSSS was carried out, which can provides some reference data for the reliability analysis of the heavy--duty gas turbine.. This shows that by using finite element method and the monte carlo method to carry out structure strength reliability analysis of maximum stress area is feasible.

Abstract: The study explores the effects of the flame-retardant properties of nano-particles on water-based fire-retardant coatings, which include the effects on thermal stability and combustion properties. The coating used by the paper is acrylate resin (VAC), which is added with 3 basic components, including fire-retardant ammonium polyphosphate, pentaerythritol and melamine (APP-PER-MEL), to form an itumescent fire retardant (IFR). Then the fire retardent is added with magnesium hydroxide (Mg(OH)2, MH) nano-particles, multiwall carbon nanotubes (MWNT) and zinc borate (ZB) nano-powders of different concentrations, to form water-based fire-retardant coatings. By adjusting and controlling the concentration ratios of flame retardant to the 3 kinds of nano-particles with different profiles, the study analyzes the fire-retardant multiplying effect of nano-particles on water-based coatings. The nano-coatings mixed in special proportion are coated on plywood. Through thermogeavimetric analyzer (TGA) and cone calorimeter (CCT), the study inspects the thermal stability and combustion properties of water-based fire-retardant nano-coatings. The experimental results show that when the fire-retardant nano-coating composed of MH of concentration 28% and MWNT of concentration 2% is compared with the fire-retardant coating added with flame retardant only, the amount of residue can be increased by around 80% at combustion temperature 580°C. Besides, when the fire-retardant nano-coating composed of MH of weight concentration 28% and MWNT of weight concentration 2% is compared with the fire-retardant coating added with flame retardant only, the maximum heat release can be decreased by about 15%. The time required for this fire-retardant nano-coating to achieve maximum heat release is delayed by around 70 seconds when compared with other samples. Besides, the char-layered structure formed during thermal decomposition of nano-coating is more compact than the char-layered structure of water-based coating composed of the flame-retardant APP-PER-MEL components only. Therefore, nano-coatings can effectively decrease the transfer of heat and inflammable volatiles to plywood surface, and can enhance the flame retardant performance of plywood.

Abstract: The early-age properties and relationships between hydration heat and autogenous shrinkage in high-strength mass concrete are investigated through analysis of the history curves of hydration heat and autogenous shrinkage. To reduce the hydration heat velocity, micro encapsulated retarder (MR) that could retard cement reaction was applied. In the result of research, the hydration temperature and hydration heat velocity of high-strength mass concrete can be decreased with the reduction of size specimen and use of the retarder. A close relationship could be found between the hydration temperature and autogenous shrinkage; the higher the hydration heat velocity, the higher the autogenous shrinkage velocity and the greater the ultimate autogenous shrinkage.

Abstract: In order to enhance the electromechanical characteristics of IPMCs actuators under low voltage, a set of anisotropic membrane surface modification techniques, including roughness along, roughness across and roughness across both directions, is proposed in this paper. Three groups of IPMCs samples based on corresponding roughness direction have been prepared to validate the these surface modification. Experiments have been made to measure the electromechanical characteristics of the samples. The results show that the IPMCs actuator with micro-grooves being across the length of the IPMCs actuator could improve the IPMCs’ tip blocking force and deflection, and it exhibits blocking forces by 10% larger than the conventional IPMCs while its displacement is approximately 8% larger. We can conclude that an appropriate anisotropic surface modification could be an effective method to create a preferred bending force and to enhance the bending margin of IPMCs actuators.