Applied Mechanics and Materials Vol. 711

Abstract: To study the effect of rock joint parameters, the joint orientation, the filling situation of joint and the distance between the center of joint and the position of penetration on rock fragmentation mechanism by tunnel boring machines (TBM) cutters, a series of penetration tests were conducted on rock-like specimens using the modified triaxial testing machine. Data of indentation load and penetration depth during the loading process were recorded and analyzed. Results show that the filling situation of joint can significantly influence the resistance of rock to penetration. The joint interface closer to the position of penetration plays a more positive role in rock fragmentation than that farther to the position of penetration. The joint orientation can greatly affect the peak indentation load, the anti-invasive factor, the crushing work as well as modes of rock fragmentation. With the increase of joint orientation, the peak indentation load, anti-invasive factor and crushing work decrease firstly, and then increase. When joint orientation equals to 60° and 90°, they reach the minimum and maximum values, respectively.

Abstract: In order to study coal cutting mechanism, particle discrete element theory is adopted to establish numerical modeling of coal cutting processes. The paper presents a brief overview of the constitutive model and calibration of the discrete element model by simulation of the Uniaxial test and Brazilian tests and analyze the movement of picks. The results show that coal effect mainly by internal tension and shear forces, which tension large value, accounted for the major role in the destruction of the coal. Cutting force and Normal force influence on pick largely, Lateral force is small influence on pick.

Abstract: Based on the characteristics of the machine, wire walking agencies, table feed system and the circuit control section has been studied in combination with all kinds of WEDM. The machine use PLC to control the campaign of wire walking agencies, using the trip switch to control motor reversing, controlling the movement of the machine table through MCS-51 series single-chip and using high-frequency pulse-way power offers a range of different pulse width of the rectangle for WEDM .In this way ,it simplifies the overall structure of the machine and improves efficiency of the feed system and cutting performances.

Abstract: A composite which is PTFE as a matrix with PEEK and carbon fiber as fillers is developed to fabricate the bush of water-lubricated journal bearings. The bush is fabricated with a new structure that a relatively large straight groove is opened in its upper part. A water-lubricated journal bearing made up of the bush and a steel sleeve is studied using purposed-built test rig. It is shown that the test bearing operates under hydrodynamic lubrication for almost all of the given conditions. The composite developed in the work is a promising material for water-lubricated journal bearings, and the new structure can be well used in water-lubricated journal bearings.

Abstract: The output characteristics of solar cell that researched as the target is analysed at different temperatures and light intensity .Combining with the equivalent circuit of solar cell, mathematical model is established .The system is simulated through MATLAB/Simulink and the data is compared with the actual one. The experimental results show that the model can well reproduce the output characteristics curve of solar cell at arbitrary condition and the error between the model and the actual output is decreased because of the series resistance. The system can satisfy the requirements of engineering design, in addition, the system can provides theoretical basis for simulation study of solar power generation system.

Abstract: Mode analysis of liquid hybrid bearing in the spindle system of high-speed roll grinder whose grinding wheel linear velocity is 80 m/s is carried out by means of finite element analysis method, and the vibration vulnerable areas of the liquid hybrid bearing are found out near the static pressure oil cavities and the diversion groove, and the former 6 orders natural frequencies are gained, furthermore, each order vibration mode is mainly presented as torsion deformation. Therefore, in order to avoid resonance vibration, the bearing should keep away from the resonance vibration frequency region in the course of practical working, and its dynamic performance can be enhanced by optimizing the structure or improving the material property of the bearing, thus, theoretical supports for developing the liquid hybrid bearing in the spindle system of high-speed roll grinder are provided.

Abstract: In the millions of years plants continue to develop and evolve for the competition of survice, the macroscopic and microscopic structure and morphology of plants may seem simple, but its specific functions, is man-made design unmatched. By observing the distribution of plant leaves, bionic design of the picks on cutting head based on phyllotaxis theory and establish its 3D model ,which fills its gap in the field of bionic design.

Abstract: The element model of a honeycomb structure is established by using ANSYS software. Then theinfluence of design parameters such as inscribed circle diameter and thicknessof honeycomb on the strength and stiffness of honeycomb structure is explored.Under a given external load condition, the honeycomb structure which satisfies the equivalent stress criteria is got by changing inscribed circle diameter,wall thickness and skin thickness of a standard structure respectively. Comparethe weight of honeycomb structure get from these three methods and generalize a method of honeycomb structure lightweight design which satisfies different requirements.

Abstract: The plane vibration model of minibus with 7 DOF is used to study ride comfort of minibus under road random input. The system frequency response characteristics based on the road input of front wheel is derived with the analysis method in frequency domain. The frequency response function, power spectral density and root mean square value of vibration response variables are determined. Ride comfort simulation software for minibus under road random input is developed with Matlab and applied to ride comfort analysis of a minibus under road random input. The results show that ride comfort of the minibus is better in the case of full load and road Class B at the speed of 70km/h.

Abstract: In order to research the prestressed concrete containment structure under Strong Earthquake, the multi-layer shell elements has been used to set up 3-d finite element model , time history and the static nonlinear analysis is carried out on the structure. Nonlinear finite element of a 1/10-scale PCCV model was analyzed and the dynamic characteristics of the model, the initial stiffness, the maximum base shear and the maximal displacement on the top of the cylinder had been calculated. Research show when ground motion reached 3g, tensile stress of concrete on wall and equipment at the bottom of the valve hole have exceeded 4MPa, but tensile stress of concrete on dome have less than 0.5MPa. The finite model calculated results are in good agreement with the results of previous papers of Pseudo dynamic test. It is concluded that this containment vessel has sufficient aseismic safety. It can provide a reference for seismic design.