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The paper is concerned with the analytical aspects of the structural optimization problems for elastic bodies in the unilateral contact with a given friction. The contact phenomenon is governed by the second order elliptic variational inequality. The aim of the topology optimization problem is to find such material density distribution function in a domain occupied by the body to minimize its normal...
Topology optimization of bodies in unilateral contact with a given friction is considered in the paper. The contact phenomenon is governed by the second order elliptic variational inequality. The aim of this optimization problem is to find such distribution of the material density function to minimize the normal contact stress. The original optimization problem is reformulated in terms of Cahn-Hilliard...
Landing-impact between lander and lunar regolith is the decisive factor to soft landing and relates directly to the safety of detection equipment. In this paper, the landing-impact process and the interaction between lander and regolith is researched using the discrete element simulation. Firstly, the landing-impact model is established based on discrete element theory and the mechanical properties...
This work aims at characterizing the formation of cone-cracks in brittle materials upon spherical indentation. The cone-cracking is simulated by the extended finite element method (XFEM) in Abaqus / Standard. The element size-dependency is reduced by scaling the damage initiation strength based on mean stress criterion and calibration techniques. The formation of a kinked-cone-crack is observed when...
anti-slide pile is the most commonly used and the most effective control technologies in Slope engineering. The current design theory is based on experiences not to consider soil arching effect, which made reasonable anti-slide pile spacing, is too small and cost is too high. In the paper, by the analysis of existing research results and the two arch-hinged arch optimal curves and instability arch...
According to prestress loss due to friction, several formulas that can be use to calculate pre-stressing tendon elongation are derived under the arrangement in straight line, circular curve or parabola layout in this paper, the solutions were proposed for different tensioning tendon and spatial pre-stressing tendon and we discussed the recurrent problems that existed in the calculation, especially...
This paper describes experimental results using a scanning electron microscope (SEM) to observe the face of diamond-impregnated bit after its drilling engineering ceramic. Wear patterns and mechanisms were analyzed. The results show that several diamond wear patterns are found in the bit face including complete crystal shape, micro fragmentation, extensive fragmentation, whole fragmentation, wearing...
The section shape of piles becomes various along with the development of piles. The additional stress in the ground due to skin friction and tip resistance of pile is different in different section shape. Using the numerical integral function of NIntegrate in Mathematica software, basing on Mindlin stress solution and referencing the idea from Geddes stress solution; The calculation method on additional...
Extrusion process of a large diameter thin-walled aluminum profile was simulated by FEM based on Deform-3D software. The results show that the material flow velocity in the bearing exit of the original designed die is non-uniform. Three times modifications were performed and simulated. The optimal design with more uniform flow velocity in the bearing exit was obtained.
Several models for steady laminar flow in short and long microchannels of arbitrary shape and aspect ratio are reviewed. The equivalent rectangle model of Muzychka and Yovanovich with the effective aspect ratio accurately predicts over 700 numerical and analytical data for fully developed flow for many non-circular microchannels. All data lie within plusmn5% of the curve for the rectangle. The general...
We fabricated two kinds of cantilever actuator and a traveling machine by using magnetostrictive Tb-Fe and Sm-Fe thin films on a polyimide substrate. No power supply cable is required for their actuation, because they are driven by an external magnetic field. The magnetostrictive cantilevers exhibited a large deflection in low magnetic fields. Their unique characteristics suggest that magnetostriction...
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