Advanced Materials Research Vols. 816-817

Abstract: A 2D time-domain boundary element method (BEM) is developed to study the fracture problems in thin piezoelectric structure. The nearly singular integrals arisen in thin structures are calculated in two ways. One is based on a nonlinear coordinate transformation for curve-quadratic element, and the other one is an analytical integration method for straight quadratic element. Numerical examples are presented to verify the effectiveness and stability of the present BEM in thin piezoelectric structure.

Abstract: In order to understand the shear strength characteristic of water-sensitive shale under the effect of water in the northwest of Hubei province, we carried out direct shear tests of shale in natural and water-saturated states along its bedding plane with original shale samples taken from the Guzhu expressway and analyzed the shear stress-displacement relationship under different normal stresses and explored the influence of water on shale shear deformation and strength characteristic. This study shows that the shear stress-displacement curve of shale in natural state and water-saturated state presents significant similarities and differences; compared with natural shale, water-saturated shale witnesses an obvious drop in its cohesive force, internal friction angle and residual angle of internal friction; shale in natural state presents apparent brittle failure characteristic while water-saturated shale to some extent exhibits ductile failure characteristic.

Abstract: In this paper, the hydration process and strength of calcium acrylate (CA) modified cement under the effects of different additives, such as, initiator-hydrogen peroxide, accelerator-triethanolamine, and cross-linking agent-butyl acrylate, were studied. Through comprehensive analysis, the optimal content of additives of initiator, cross-linking agent, and accelerator is ascertained 3%, 10% and 3%, respectively. On the condition of optimal content of additives and CA, it can be obtained that CA can increase the exothermic rate of cement within one hour and accelerate the exothermic rate in the induction period, shorten the time of the induction period, and speed up the initial setting time of cement. Besides, CA can inhibit the transformation of AFm from AFt, improve the dispersion of cement paste, make later hydration more fully, and promote later strength.

Abstract: In this study, a non-contact liquid crystal thermography (LCT) method was developed for surface temperature measurements on the micro- and micro-tubes with the diameters of 2000µm, 1000µm, 838µm and 686µm. In the single-phase heat transfer experiments, the fully-developed flow heat transfer data from laminar to turbulent regionswere obtained under the uniform wall heat flux boundary condition. The experiment system was verified with the macro-tube of 2000µm diameter tube. The results showed that buoyancy effect was not observed in the laminar region when the tube diameter was less than 1000 µm. In theturbulent region, the heat transfer data trend followed with the classical turbulent correlation. Furthermore, the current LCT results showed the similar trend when compare with the published LCT data of Yang and Lin[1].

Abstract: Micro Electric Discharge Machining (μ-EDM) is a non-traditional machining process which is used for drilling micro holes in a high strength-to-weight ratio advanced engineering materials like shape memory alloys that have many applications in the field of aerospace and medical sciences. However, in order to achieve the desired output responses the process control parameters of the machine have to be set at an optimal setting. In this research work, an investigation has been made to study the influence of the input parameters (such as capacitance, discharge voltage and electrode material) on the micro-EDM process output responses (such as MRR, TWR, Ra and circularity of the micro-holes) while drilling the micro-holes on Ni-Ti shape memory alloy. The full factorial design based study resulted in a set of recommended values for input variables to obtain the desired output. Mathematical predictive models have also been developed, which predict good values for the output responses.

Abstract: Definition of homology gene, mutual exclusion gene, formulations gene and compatriots gene set has been given based on the characteristics of the energetic formulation components in this paper. The complex formula chromosome resolution rules have been designed to solve the energetic formulation component burst speed estimate problem combined with the GEP theories and test techniques. The test results showed that the performance prediction error of the detonation velocity is less than 3%.

Abstract: Using the finite element method analysis the influence of the enhanced body size to stress concentration factor and stress distribution between the enhanced body in nanocomposite coating and the matrix interface. By preliminary calculation, the paper predicts a trend that the stress distribution on the interface reduces with the decreases of the enhanced body size and the stress concentration. Theoretically proved the iomportant rule that in the field of organic composite materials if you want to improve the performance of composite materials ,the enhanced body size need to be reduced.

Abstract: With the weight-reduction requirement for transportation tools, more and more plastics and composite materials will be applied. However, the connection between plastics, polymer-based composite and traditional metal, such as steel or aluminum, possibly become the weakest region and thus decrease the structural safety, therefore, its mechanical properties should be investigated. In this paper, a typical single-lap joint was analyzed experimentally and numerically under the three-point-bending loads, and the results were compared and finite element model was updated. Based on the validated simulation technology, three other joints were simulated and all joints were compared, and suggestion for design of composite joints was provided.

Abstract: This paper discusses the research conducted on prepreg composites interfaces engineered with, either carbon nanotubes (CNTs), or core shell micro-particles (CSMs). The emphasis is given on the fractography details that highlight various mechanisms involved in strengthening the ply-to-ply surface contacts due to the addition of these nanoand micro-particles.

Abstract: The variation rules of strength, load, and reliability of cutting tool are studied with a change in time, and a model is established for dynamic reliability of cutting tool under the random load acting. By combining the theory of reliability design with the method of sensitivity analysis, the computational method of dynamic reliability sensitivity design with arbitrary distribution parameter is proposed based on the methods Edgeworth and perturbation, and the problem of dynamic reliability sensitivity design of cutting tool distributed arbitrary distribution is solved as well as the variation rules of dynamic reliability sensitivity are given. The variation of reliability is studied as design parameters change a little, which provides theoretical data for dynamic reliability design of cutting tool