Applied Mechanics and Materials Vols. 170-173

Abstract: The interface transition zone (ITZ) has a significant impact on the concrete’s mechanical properties and fracture modes. For the influence of ITZ’s strength and elastic modulus, the extended finite element method (XFEM) is adopted to simulate the mesostructure failure process by virtue of random aggregate model under uniaxial tension. The results show that ITZ’s strength and elastic modulus have a certain effect on the mechanical properties and fracture modes. With the tensile strength of ITZ increasing, the fractured modes transit from single coalescent crack to multiple non-coalescent cracks and the fracture energy increases, the ductility of concrete is enhanced. With the elastic modulus of ITZ increasing, the concrete’s elastic modulus increases, the tensile strength and the fracture energy decrease.

Abstract: Volumetric errors are the major contributor to the dimensional errors of a workpiece in precision machining. Error compensation technique is a cost-effective way to reduce volumetric errors. Accurate modeling of volumetric errors is a prerequisite of error compensation. In this paper, a volumetric error model was proposed by using neural networks based on ant colony algorithm. Finally, a volumetric error compensation system was developed based on the proposed model, and which has been applied to a CNC machine tool in daily production. The results show that the volumetric errors are reduced and the machining accuracy of the machine tool is improved.

Abstract: The boom with closed circuit in Hydraulic Excavators, which is made up of motor, hydraulic pump and accumulator, was put forward based on analysis of the operating condition of ordinary hydraulic excavators and mathematical models of system were built. Power characteristics of main power elements were obtained under typical operating conditions, and then the energy consumption characteristics were analyzed. The results show that the installed power and energy consumption will be reduced using boom with closed circuit, and no-load drop and full load rise of boom are the worst operating conditions.

Abstract: This paper studies the British Royal Marines Barracks Building within the site of the Beiyang Naval School on Liugong Island, Weihai City, Shandong Province, and deciphers its background, layout, structure and decorative characteristics. It takes the British Royal Marines Barracks Building as an example to explore the historical and cultural value contained in the architectural heritage built in Weihai during the British lease period in 1898 to 1940. It provides some valuable data for research, conservation and use of the historical architectural heritage built in this special period.

Abstract: Based on the engineering practice of the large section roadway in Zhaozhuang Mine, which has composite roof of mudstone and sandy mudstone, and the shale floor, and did the support optimization design of large section roadway through three-dimensional numerical simulation by using the FLAC3D. To optimize the row spacing between the bolt, it carried out nine group test of numerical simulation program to analyze, six group test of numerical simulation program to analyze the length of the anchor cable, and five group test to analyze the distance of the anchor cable. Through these, the effect of the bolt spacing, the length of the top anchor cable, the anchor cable spacing and other support parameters to the supporting are got, and putting forward an anchor - anchor cable integrated supporting parameters optimization program to match the large section of the composite roof. Results show that it is reasonable to use 950mm x 900mm of the bolt spacing in design, and 7.5 meters length in design the top anchor cable.

Abstract: Steel bifurcated pipe is one important part of the water diversion buildings in a hydropower station. And its hydraulic characteristics are crucial to reduce the head loss of the bifurcated section. The numerical simulation was carried out with spherical trifurcate branch pipe, shell type trifurcate branch pipe without deflecting plates and shell type trifurcate branch pipe with deflecting plates under a serious of operating conditions based on a case study. After this, the flow conditions and the head losses in the bifurcated sections were analyzed. The shell type trifurcate branch pipe with deflecting plates had the most advantageous hydraulic characteristics of the three schemes. The shell type and the deflecting plates improved the flow condition effectively. The scheme could improve the flow condition and reduce the head loss of the bifurcation section effectively. The results might provide some references to the bifurcated pipe design and operation.

Abstract: Prestressed anchor-cables supporting technology has become the primary measure for reinforcing the roadway of deep coal mine and complex geological conditions. In this paper, fast Lagrangian analysis of continua (FLAC3D) code is used to analyze the laws of stress, deformation and failure of surrounding rock with and without roadway supporting by anchor-cables. The supporting action mechanism and effect of anchor-cables have been investigated into systematically. The results show that the anchor-cables supporting is adopted at reasonable positions of the roadway in good time which can improve the stress states of deep surrounding rock, decrease the range of failure zone around the roadway, control the roadway deformation effectively and maintain the stability of roadway.

Abstract: In order to provide the best technic parameter for hot pressing, the diffusion bonding temperature fields of Be/HR-1 stainless steel under different cooling methods were simulated by the finite element method. The results show that high temperature parts occur in stainless steel center zone in water cooling and air cooling, and the interface cooling rates follow respectively equation of T = 0.0297 t ² - 9.3223 t + 1017.6 and equation of T = 0.002 t ² - 0.7702 t + 1014.8. In funace cooling, high temperature part moves to beryllium center zone and the interface cooling rate follows equation of T = -0.0192 t + 1018.8. While the heat transfer coefficient (h) is taken as 5, the temperature distribution of both sides on the interface is symmetric and temperature gradient is the lowest, so the hot stress on the interface is reduced effectively to improve the diffusion bonding strength, which results fit with the experience ones well.

Abstract: Non-rigid image registration is an interesting and challenging research work in medical image processing, computer vision and remote sensing fields. In this paper we present a free form deformable algorithm based on NURBS because NURBS (Non-uniform Rational B Spline ) with a non-uniform grid has a higher registration precision and a higher registration speed in comparison with B spline. In our experiment we compare the NURBS based FFD method with the B spline based FFD method quantitatively. The experiment result shows that the algorithm can improve highly the registration precision.

Abstract: Superhydrophobic materials can be used in building materials, such as glass, ceramics, and concrete, which keep buildings clean. Slip phenomenon plays an important role on the hydrophobic of solid surface. Based on the model of Volume of Fluid (VOF) for given inlet velocity and outlet pressure, the unilateral slip flow of three typical physical models (rectangular, triangular and round head shape physical model) in superhydrophobic microchannel are numerically simulated. Furthermore, the hydrophobic laws are analyzed in the condition of different shapes and dimensions, and the optimal dimension and shape of microstructure is obtained. Numerical simulation results show that the slip happens in the air-liquid interface of the microchannel, and when the micro rib’s height is 40μm, the slip velocity for rectangular physical model reaches to 125mm/s. When the micro rib’s height is at 50μm-100μm, the round head shape physical model has the largest slip velocity of 350mm/s. This study plays an important guiding role for the design and application of the superhydrophobic surface.