Applied Mechanics and Materials Vols. 275-277

Abstract: A hyperbolic tangent function model was used to make analysis for the rock mass displacement and deformation caused by underground mining, the model is verified correctness through real engineering practice. The cracking damage of the above buildings was analyzed using the model; the result could provide guidance for the underground mining and safe production.

Abstract: Abstract. Through the uniaxial compressive test, the mechanical parameters and the complete stress-strain curves were obtained, which presented a brittle failure of the mudstone samples of the No.2₁ coal seam in West Henan. Soft rock was regarded as no brittle in its failure usually, but in fact it was exactly. It showed that yield failure occurred in some areas and tension occurred inside the specimens because of the samples’ inhomogeneous deformation. The comprehensive decision method of mining surrounding rock’s brittleness was suggested: the brittleness index was more than 25; the strain of rock at failure was less than 3%, and there was brittle stress drop in the complete stress-strain curve.

Abstract: Based on 2-D PFC, non-circular particle with direction was constructed and specimens with different distribution of long axis orientation were established. Loads were applied in vertical direction. Changes of fabric such as the long axis orientation, particle contact direction and particle contact force in the process of loading were analyzed. It was shown that the larger angle of the loading direction and the long axis orientation, the greater strength of specimen and more anisotropic. It was proved by the numerical analysis that tendency of particle contact stress direction is the micro – mechanics reasons of soil’s anisotropy under loading.

Abstract: A series of compression tests were conducted on the samples taken from compacted soil site in Lulling, in order to investigate the compressibility of compacted loess in different water content and different compaction energy. Through statistics analysis of the testing data, the stress-strain curve of compacted loess could be expressed with Hyperbolic form. And the relation between initial tangent modulus and water content change coefficient was founded by introducing the water content change coefficient. The result shows that at the same compaction energy, the initial tangent modulus decreases and the ultimate strain increases as water content increases; while at the same water content change coefficient, the initial tangent modulus increases and the ultimate strain decreases as compaction effort increases.

Abstract: The outcomes of a research focusing on water modeling and Fluid-Structure Interaction by ALE and SPH in LSTC/LS-Dyna971 are presented in this paper. Firstly the water impact behaviors of a rigid wedge are modeled with water region by ALE and SPH. The size of fluid elements plays critical role to the numerical results, so three different cases varied in mesh or particle spacing both in ALE and SPH methods are detailed discussed. The numerical results are compared both one to the others and to the experimental and theoretical results in terms of vertical velocity and slamming force, which can be concluded that the more elements modeled in the simulation, the better approximation with the experiment results. An additional discussion of propagation of pressure wave by SPH and CPU time are also presented.

Abstract: The effects of different concentration of β-cyclodextrin (β-CD) (0.5%, 1.0%, 1.5%, 2.0% and 2.5%) on the suppression of dehydrate and hardened during storage hardened were evaluated. The results indicated that β-CD could improve the quality of frying chestnut. A certain content of β-CD could decrease the dehydrate and hardness during storage. The addition of 1.0% β-CD can solve the frying chestnut dehydration and harden during storage effectively.

Abstract: The numerical investigations presented in this paper deal with active flow control approach at the rear end of the Ahmed body model with the slant angle of 25°.Results of the velocity, pressure and vorticity field demonstrate the main reasons that cause the pressure drag. The influence of the spanwise and streamwise vortices rolling up from the slant and the edges on the recirculation zone behind the body is examined. A control slot is set on the separated line at the conjunction of the roof and the slant. Two different actuation concepts by blowing and suction steady jets through the slot lead to a drug increase of 5.61% and a drug reduction of 13.20% with the efficiency of 12.53% respectively.

Abstract: This study presents a scaled-down single fuel assembly experiment to simulate the fuel in the spent fuel pool (SFP). From experiment results, this study obtained the relationship among pressure drop and velocity, the viscous resistance and inertial resistance factor. In computational fluid dynamics (CFD) simulations, the large number of fuel rod bundles is approximated with porous medium technique that imposes similar flow resistance to the motion of the fluid. Difference of the pressure drop between numerical and experimental results is within acceptable deviation.

Abstract: In this paper, we construct the multi-scale and level set algorithm of the parameter recovery for the elastic wave equations in the fluid-saturated porous media. Firstly, based on the Biot theory, we apply the multi-scale method to simulate the propagation of 2-D elastic wave in fluid-saturated porous media. Secondly, the level set method is introduced to the general parameter estimation problem.

Abstract: The lubrication of external liquid with supercavity has been the goals of specialists for many years. Either ventilated cavity or natural cavity is firstly related to multiphase flow. In this paper, in order to quantitatively predict the cavitating flow especially the ventilated supercavity and understand the structure of flow field in the cavity, two kinds of multiphase model including the homogeneous flow model and the two-fluid model were adopted separately. Besides, SST and DES turbulence model are used for steady and unsteady simulations. By comparing the simulating results with experimental results in water tunnel, the two-fluid model was proved to have the high accuracy in predicting the ventilated supercavity including the cavity shape and lift coefficient of the vehicle. On the other hand, for natural cavitation, the mixture model and the two-fluid model have little difference in predicting the pressure coefficient, however, the two-fluid model can give more detailed flow field.