Applied Mechanics and Materials Vols. 291-294

Abstract: The mechanical behavior of a compacted unsaturated clay soil was experimentally investigated. Volume changes were investigated using a conventional odometer cell under a series of constant confining pressures, following a wetting path. The special loading paths were utilized to reflect field conditions associated with the compacted earth structure in earth filled embankment. The soils used in the experiments were taken from an earth dam. The compacted specimens were consolidated under k0-oedometer conditions. The volume change and the water content variation were measured during the tests. The influence of the confining pressure and the initial water saturation were taking into considerations. The experimental results show that the volumetric deformation properties of the remolded unsaturated soil could be expansive and/or contractive, depending on the confining pressure and the initial water saturation. It is also observed that for the mediate confining stress, there volumetric deformation of specimen applied to wetting loads has a transition from dilation to contraction.

Abstract: Normal form theory is robust and useful for direct bifurcation and stability analysis of nonlinear differential equations in real engineering problems. This paper develops a new computation method for obtaining a significant refinement of the normal forms for high dimensional nonlinear systems. In the theoretical model for the nonlinear oscillation of a composite laminated piezoelectric plate, the computation method is applied to compute the coefficients of the normal forms for the case of one double zero and a pair of pure imaginary eigenvalues. The algorithm is implemented in Maple V and the normal forms of the averaged equations and their coefficients for nonlinear oscillations of the composite laminated piezoelectric plate under combined parametric and transverse excitations are calculated.

Abstract: A series of nanoclay reinforced thermoplastic polyurethane with shape memory effect have been successfully synthesized via two-step polymerization process. The polyurethanes are composed of polycaprolactonediol, palm oil polyol, 4,4’-diphenylmethane diisocyanate and 1,4-butanediol. Nanoclay was added in order to improve the overall properties of the pristine polyurethane. Besides, the addition of palm oil polyol is believed to enhance the crosslinking process and further improve the properties. X-ray diffraction result showed that there is a decrease in crystallinity of polyurethane nanocomposites as clay is added. Good shape memory and mechanical properties of resulting polyurethane nanocomposites were obtained in this work.

Abstract: This paper establish feather piece section, volume and weight and other related mathematical calculation model and its corresponding moment of inertia computation model, then establishes a mathematic model to calculate the square of a natural feather rachis’ section by image processing and the method of least squares. Meanwhile, the formulae for calculating the volume and mass of the natural feather rachis are also provided. The results out of calculation basically accords with those out of actual measurement, which proves the feasibility of the formulae. This paper works out the formula for calculating the moment of inertia of natural feather when the arch degree is not taken into consideration, and it also puts forward a formula for calculating the moment of inertia of natural feather with an insertion angle. This paper first puts forward the feather piece model and moment of inertia calculation model, which to help badminton flight characteristics research and have practical value.

Abstract: Severe plastic deformation（SPD）methods have been the subject of intensive investigation for preparing bulk ultrafine-grained materials in recent years. This paper introduces a new severe plastic deformation (SPD) process named as C-TE process which combines the Twist Extrusion with Extrusion against the asymmetric deformation of TE process. and the distribution of effective strain and stress of the sample and the variation of load with time and its influence on the deformation were investigated by computer simulation with Deform-3D software . The results reveal that C-TE process can significantly slow uniform phenomenon,and a sample of homogeneous deformation can be obtained by the improved process.

Abstract: In order to optimize the processing parameters of TiC/steel composite materials, in-situ TiC particle reinforced steel-based surface composites were prepared by vacuum evaporative pattern casting (V-EPC) infiltration process, and the structure and interface of the composites were investigated. The results show that, TiC particle size with Ti-C-20wt%Fe reaction system was much smaller than the composite with Ti-C reaction system in the same location of the composites. In the composites, the TiC particle size and volume fraction increased and spherical degree dropped from the tradition layers (interface between the substrate and the composite layer) to the outer surface. But the increase of TiC particle size (1-3μm) and volume fractions (25.8%-43.5%) in the composite with Ti-C-20wt%Fe reaction system was obviously lower than that of TiC particle size (1-10μm) and volume fractions (12.3%- 67.7%) in the composite with Ti-C reaction system. The bond zone between TiC particles and the matrices was totally metallurgical bonding without apparent interface. Comparing with the composite with Ti-C-xFe reaction system, the tradition layer with Ti-C reaction system has a poorer internal quality. The forming process of TiC in situ synthesized reinforced steel substrate surface composites prepared by V-EPC infiltrating process was infiltrating of the melting and carbothermal reactions of C and Ti powder the result of joint action.

Abstract: The welding quality in multi-pass welding is mainly dependent on the pre-heating from pervious pass or root-pass welding. In this study, a Mahalanobis Distance and normal distribution method is illustrated and employed to determine whether welding faults have occurred after each pass welding and also to quantify welding quality percentage. To successfully accomplish this objective, sets of multi-pass welding experiment were performed with different welding parameters in each pass; the welded samples of SS400 steel flats adopting the bead-on-plate technique were employed in the experiment. The result of current and voltage for each pass is obtained through the real time mentoring systems. In order to verify the effect of the performance and weld quality of the different weld-pass, Mahalanobis distances for voltage and current values were calculated and used for qualitative and quantitative analysis with comparison to values obtained from the root-pass as reference welds. The results of the experiment and statistical analysis have demonstrated that the weld faults after each weld pass is feasible.

Abstract: Ti-Al-Si-N films were deposited on 1Cr11Ni2W2MoV steel at different N2 flow rates from 0 to 600 sccm by AIP using a Ti60Al30Si10 target. The effects of the N2 flow rates on the deposition rate, composition, microstructure, microhardness and adhesion property of the films were investigated by SEM/EDS, XRD, microhardness and scratch tests, respectively. The results show that the deposition rate of the films decreased initially and then began to increase at N2 flow rate higher than 300 sccm. The microhardness of the films increased with the N2 flow rate except a slight drop at 450sccm. The evolution of adhesion property of the films was very similar to that of microhardness. All the Ti-Al-Si-N films had B1 NaCl structure with (220) preferred orientation except that at 600 sccm. The effects of the N2 flow rate on the properties of the Ti-Al-Si-N films were discussed.

Abstract: The paper summarized the technical properties and source of recycled concrete based on the research literature. It mainly includes the mechanical properties, physical properties, the impermeability, dry shrinkage properties and the uncracking of recycled concrete, and economic feasibility of recycled concrete. The feasibility of recycled concrete use are proposed, and economic benefit, social benefit environmental protection benefit is obvious.

Abstract: To create the form of products has a certain regularity as same as the form of nature,and closely linked with social and cultural,ethnic customs and habits.When a car brand after years of development, some of the unique styling characteristics will remain in their models down to become a symbol of the shape of its brand symbol and logos.With the development of the times and technology, hatchback car due in large part to save human resources become the main direction of future automotive development.The object is hatchback sedan of Volkswagen brand golf series,starting from its styling features and make a comparative analysis of the form of body shape,the development of light form and design texture,and combined analysis of the Golf market sales volume sampling and Golf Volkswagen brand sales scale drawing.It shown that automotive styling morphology inextricably linked with the development of accurate market positioning and era.