Papers by Keyword: Multi-Phase Materials

Abstract: This paper deals with the large deformation analysis of partially saturated soils subjected to dynamic loading. The so-called ‘mixture’ theory is employed to consider the hydro-mechanical coupling involved in this kind of problem. The finite element method is used to discretise the problem domain and the generalized-α algorithm is employed to integrate the governing equations over time. Some of the most challenging aspects of dynamic analysis of partially saturated soils will be discussed. One of the key challenges is selecting a consistent constitutive model within the theory of mixtures that can incorporate the pore suction forces into the description of stress. The necessity of such incorporation has frequently been reported in experimental studies of unsaturated soils. To tackle this problem, a unique strategy for integrating the constitutive model for unsaturated soils is adopted. Moreover, an absorbing boundary condition, which prevents wave reflection from rigid boundaries, is introduced and implemented into the numerical algorithm. Finally, a solution for the problem of dynamic compaction of soil in a partially saturated condition is presented.

Abstract: Two Models for Estimating the Effective Thermal Conductivity (k_E) of Multi-Phase Materials Are Comparatively Investigated. the First Model Is the Effective Medium Approximation (EMA), which Is Based on the Extension of the Percolation Theory. the Second Is the Randomly Mixed Model (RMM), a Numerical Method in which All Components Are Seen as Cubech_cubecucube in Shape and Are Randomly Dispersed inside the Space. Two Models Can Be Directly Applied to Multi-Phase Media without Empirical Parameters. Compared with Experimental Data of Food Materials in the Literature, Two Models both Give Good Estimations of the Temperature-Dependent K_E.

Abstract: The study presents the latest developments in terms of speed and integration of the electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) techniques. The microstructural features and texture of a commercially available tool steel have been analyzed by simultaneous EBSD/EDS measurements. The EDS data was used for confirming/correcting the EBSD results as well as for detecting the presence of ultrafine carbide precipitates. The results indicate the formation of two different types of carbides inside a ferritic matrix. Most of the matrix was found to be composed of fully recrystallized grains with average diameters around 10 microns. Zones characterized by finer submicron scale grains could also be identified locally as well as grains containing networks of subgrain boundaries. This study demonstrates that the combination of the two techniques, i.e. EBSD and EDS, results in a powerful tool for a fast, reliable and complete characterization of multiphase materials.