Advanced Materials Research Vols. 261-263

Abstract: The experiments of compressive strength about maix proportion of concrete are repeatedly done, adopting orthogonal experimental method. In this experiment, dry separation waste rocks and mine tailings in mining slag of Qidashan Iron Mine which is subsidiary company of Anshan Iron and Steel Corporation are used instead of traditional fine and coarse aggregate concretes. Then the optimized mix proportion is determined to make the concrete small hollow blocks. Sample test shows that it is feasible to make load bearing concrete small hollow blocks which can meet national standards.

Abstract: The objective of this study is to investigate the possibility of using waste plastic as an additive to modify asphalt mixtures thereby reducing the waste plastic stream in our environment. High density polyethylene plastic bags obtained from the retail store were shredded into chips and added into asphalt mixtures at the rate of 0% (control sample), 2, 5 and 8% based on binder weight. Three different temperatures of 4, 21.3 and 39.2°C and frequencies ranging from 0.1 to 25 Hz were used in the dynamic modulus test. It was found that most of the asphalt mixtures modified with waste plastic have higher dynamic modulus when compared with the control samples. However, no significant trend on phase angle was found among all the samples tested based on the test results. In this study, it was found that the modified asphalt mixture with 2% waste plastic had the highest dynamic modulus and phase angle. Based on the test results, it was found that plastic modified asphalt mixture will have a better performance under intermediate and high temperature conditions.

Abstract: How to efficiently dispose of the urban water-supply plant sludge has become an urgent task of controlling pollution caused by municipal solid waste. This paper is an experiment on autoclaved sludge brick, which is mainly made of sludge from the water-supply plants, fly ash, lime, sand and cement, integrated with the manufacturing process of autoclaved fly ash brick. By orthogonal optimal process, we get the optimal parameters for making sludge bricks as follows: W _sludge : W _ash : W _lime = 15%: 45%: 15%, stirring intensity being 1400r/min, forming and curing condition being the constant temperature and humidity Curing Box (60 °C, humidity 95%), and autoclave curing condition being 1.2Mpa (time 10h). With the optimal parameters, the compressive strength of the produced bricks reaches 20.8Mpa, and its flexural strength reaches 5.4 Mpa. Besides, stirring conditions, forming and curing conditions together with the influence of curing conditions on autoclaved sludge bricks’ mechanical properties are discussed.

Abstract: In the present study, the dynamic Vreman model based on the global equilibrium between the subgrid-scale dissipation and the viscous dissipation with a global model coefficient are applied to large eddy simulation of turbulent flow in complex geometries. Distributions of pressure, velocity and vorticity as well as some flow structure are gained, which is helpful to examine the performance of SGS model and understand the flow characters in complex geometries.

Abstract: The paper studies the nonlinear vibrating mechanical behaviors of double-walled carbon nanotubes (DWCNTs) with the initial axial stress under the temperature field. The DWCNTs are modeled as double elastic shells coupled together through vdW interaction between inner and outer nanotubes. Based on the model, the relation between the amplitudes and the frequencies of the tubes is achieved. The results show that the initial axial stress could crucially affect the topological forms of the amplitude-frequency curve, whereas it is insensitive to the amplitude ratios in DWCNTs. Meanwhile, it is also concluded that the temperature change is significant for natural frequency, but weakly affects intertube frequency and amplitude ratios as well as amplitude-frequency curve.

Abstract: In this paper, the nonlinear deflection curve equation of simply supported beam is converted into an algebraic equation based on a new method that combines with the Modified Differential Method and Newton Iteration Method. The conclusion drawn by comparing the analytical solution and numerical results of simply supported beam’s equation with uniform load shows that the method is precise and efficient for solving nonlinear differential equations. We also analyze the case of simply supported beam with variable cross-section and get the same conclusion.

Abstract: England (2006) proposed a novel theory to study the bending problem of isotropic functionally graded plates subjected to transverse biharmonic loads. His theory is extended here to functionally graded plates of transversely isotropic materials. Using the complex variable method, the governing equations of three plate displacements appearing in the expansions of the displacement field are formulated based on the three-dimensional theory of elasticity for a transverse load satisfying the biharmonic equation. The solutions may be expressed in terms of four analytic functions of the complex variable, in which the unknown constants can be determined from the boundary conditions similar to that in the classical plate theory(CPT). The elasticity solutions of an FGM annular plate under a uniform load are derived. A comparison of the present results for a uniform load with existing solutions is made and good agreement is observed. The influence of boundary conditions, material inhomogeneity and radius-to-radius ratio on the plate deflection and stresses are studied numerically.

Abstract: To consider the material properties of functional gradient beam structure change along the thickness. In this paper, the wavelet multi-scale method is used to solve beam differential equations with initial or boundary conditions. An operational matrix of integration based on the wavelet is established and the procedure for applying the matrix to solve the differential equations is formulated, and gets the stress of the beam when the material properties of gradient beam take arbitrary function. The results show that the proposed way is quite reasonable while comparing to the exact solution.

Abstract: In mechanical engineering, earthquake engineering and modern municipal construction, semi-cylindrical gap and shallow-buried inclusion structure are used widely. In this paper, Green's Function is studied, which is the solution of displacement field for elastic semi-space with semi-cylindrical gap and multiple shallow-buried inclusions while bearing anti-plane harmonic line source force at any point. In the complex plane, considering the symmetry of SH-wave scattering , the displacement field aroused by the anti-plane harmonic line source force and the scattering displacement field impacted by semi-cylindrical gap and multiple cylindrical inclusions comprised of Fourier-Bessel series with undetermined coefficients which satisfies the stress-free condition on the ground surface are constructed. Through applying the method of multi-polar coordinate system, the equations with unknown coefficients can be obtained by using the displacement and stress condition of the cylindrical inclusion in the radial direction. According to orthogonality condition for trigonometric function, these equations can be reduced to a series of algebraic equations. Then the value of the unknown coefficients can be obtained by solving these algebraic equations. Green's function, that is, the total wave displacement field is the superposition of the displacement field aroused by the anti-plane harmonic line source force and the scattering displacement field. By using the expressions, an example is provided to show the effect of the change of relative location of semi-cylindrical gap , the cylindrical inclusions and the location of the line source force. Based on this solution, the problem of interaction of semi-cylindrical gap , multiple cylindrical inclusions and a linear crack in semi-space can be investigated further.

Abstract: Analysis of the negative moment near re-entrant corner in different thickness of different gap plates under the vertical distribution load. Discovered that reduced the thickness of this irregular slab also to be possible to satisfy the supporting capacity and the normal operation requirements.