Abstract:Based on the real size and constrain of the wet clutch, the friction pair of temperature, stress fields coupling model, and the heat convection coefficient model are established. The transient thermal-structural coupling and the thermoelastic instability of the phenomenon of friction discs generated in overload tests are numerically simulated and analyzed with ANSYS/LS-DYNA. Additionally, the distribution of the hot spots in the circle direction and surface of the friction discs are revealed, the distribution of the stress and strain caused by the thermoelastic instability is analyzed and tested. The results show that hot spots and contact pressure are mutual promotion. The thermal expansion and stress concentration caused by temperature gradient lead to steel disc warp. The heat fading caused by the thermoelastic instability leads to steel disc failure.

Abstract:Analysis of the mapping and transferring mechanism, and the sensitivity of quality characteristics of Complicated Electromechanical Products (CEP) reveal that the coupling of functionality and structure, and uncertainty in their mapping relations are important factors that influence the quality of CEP. By integrating the principals of Axiomatic Design (AD), this paper proposes a concept of decoupling design for quality characteristics of CEP. A model for decoupling control in the mapping processes of CEP is presented. In the model, formation-process of quality characteristics of CEP is transformed into iterative zigzagging decomposition and mapping between functional-domains. Then mapping matrixes are utilized to facilitate product designers to identify coupled quality characteristics in CEP, and to reduce complexity in function and physical structure and the product development. The model presented is used in the design of the transmission system in the first direct-drive hobbing machine in China, which effectively reduces the complexity of transmission system of hobbing machine and improved gear hobbing accuracy.

Abstract:To identify internal combustion engine (IC engine) noise, a mathematical model is established, and the corresponding program is developed. By introducing global thresholds to decrease noise in the wavelet transforms program, the anti-interference of the program can be guaranteed, the spectrums of the combustion noise and mechanical noise are separated, and their A-weighted sound power levels are figured out. Taking a CG125 style motorcycle engine for an example, theoretical examples that include different interferential noises are constructed to simulate the identification and to validate the accuracy and practicability of the program. Results of the identification show that the spectrums of the combustion noise and mechanical noise before and after separation are agreed well; errors of A-weighted sound power level are all less than 0.6 dB.

Abstract:To research the dynamic characteristics of the permanent magnet AC servo precision drive system coupled with multi-factors, the experiment system is constructed with PMAC as the core and IPC as the support platform. Through software prototype system, response signals such as the current, speed and torque are acquired when the system is in the no-load and in the loading operating state, then the theoretical analysis results are compared with the experimental results. So the experiment validates that the electromechanical coupling analysis of the system is correct. This research helps to analyze the influence mechanism and law that the design parameters and electromechanical coupling parameters exerted on the system performance. At the same time, the research is beneficial for dynamic design of the permanent magnet AC servo precision drive system.

Abstract:Torque control is the key to control the shift quality in dual clutch automatic transmission system. Based on the analysis of shift process of DCT, a dynamic model of shifting is built, torque and time switch influence on shift quality are analyzed, and a method in which the pressing force of dual clutch is controlled through actuating mechanism to realize the control of shift quality is put forward. Aiming at one type of vehicle mounted with DCT, a simulation model of shift process is built and simulated, and the experimental analysis of shifting control characters is carried out. The results indicate that the control strategy can control shift quality well.

Abstract:Design optimization of Magneto-rheological (MR) dampers is important to meet engineering applications and obtain MR dampers with better performance compared with that designed by conventional design methods. Optimal design of MR dampers in vehicle based on Finite Element (FE) is proposed. A mathematical model to describe optimization problem is constructed. In the optimization, the special cylindrical volume filled with active fluid is considered as the objective function, and the controllable range of damping force is constrained to satisfy the requirements of semi-active control system in vehicle. An optimization procedure is constructed via a commercial finite element method parametric design language. Optimization design of the MR damper with valve mode in vehicle is performed by using the optimization tool developed. The results show that the optimal MR damper has minimum volume, reasonable magnetic flux density distribution, effective energy consumption and the controllable damping force to satisfy the requirement of semi-active control system in vehicle. The results demonstrate the effectiveness and feasibility of the proposed optimization approach.

Abstract:To investigate the spatial electric field with the point-plate electrodes configuration, variations of the electric field intensity are analyzed for absolute air dielectric and liquid dielectrics contained in air dielectric based on the finite element method of numeric computation. The results show that the electric field intensity of the spatial electric field is great non-uniform with the point-plate electrodes configuration for absolute air dielectric, and it can be increased rapidly at the nozzle point to achieve a maximum value. Single oil drop existed in air dielectric induces a biggish deformation of the gradient of the electric field intensity in its neighbor field. Many oil drops along with horizontal distribution have an obvious tensioning operation on the electric field, so the electric field intensity on the normal at the nozzle point has an evident augment for overlapping effects among the oil drops, and it can spread electric corona area of the total spatial electric field.

Abstract:Aiming at site management problems of machining job shop, a site tools management method based on dynamic distribution for machining job shop is proposed. According to the method, the site dynamic distribution plan of machining tools is generated. A site tools distribution management information system is developed. The function and information models of the system are presented. With the system, dynamic distribution and recycling of machining tools and materials is realized. As a result, the inventory of machining tools is reduced, and the productivity is improved. The system has been applied in a machining job shop with satisfied result.

Abstract:A product ontology screening method which can be used in variant design is proposed. With the support of complete ontology view of product resources, the product functional requirement and structural characteristics are converted to demand constraints, which are used to screen product ontology. For different screening hierarchies and objects, different screening rules such as pattern matching, case matching combined with manual decision and auto matching on the basis of case-based reasoning are adopted. The semi-automatic screening method with human-computer cooperation has impressive effectiveness on the improvements of the accuracy of design schemes and the flexibility and efficiency of design process. Finally, a variant design supporting system for building door and window is developed, which proves the feasibility and effectiveness of the method.

Abstract:Aiming at the urgent needs of those manufacturing factories of hobbing machine and their consumers, who want to improve the quality of fault diagnosis in their after services, and reduce the costs of seeking for faults, a networked fault diagnosis expert system for hobbing machine tools based SPF tree (System-Phenomenon-Fault) is put forward. The operation model of this web-based system and the architecture of expert system are brought out firstly. Based on them, some key technologies are discussed, such as the methods of multi-source data acquisition, knowledge representation, the reasoning mechanism of the knowledge system, and the network architecture based on P2P(Peer-to-Peer). Above all, the implementation methods of knowledge representation and reasoning mechanism based SPF tree are the points, which include the SPF’s definition, birth, description of elements, growth of tree trunk, mathematics description, learning-self process, statistic, retrieving and et al. A prototype system based on this study is tried out in a hobbing machine company and its feasibility has been verified in the application.

Abstract:Based on the principle of heat transfer theory and finite element method (FEM), a model for power cable thermal field and ampacity computation has been developed by adopting the soil region division method. The soil region around the cable is divided according to the difference of the soil thermal resistance. Based on the structural parameters of XLPE cable and the physical parameter of the laying area, different layers temperature distribution of XLPE cable is analyzed through the model, and the dichotomy is employed to calculate the cable ampacity. Comparing the calculated result by this method with the calculation by the standard, shows that compared to IEC60287 standard, the model has high-accuracy and is more convenient to the external environment. Through simulation example, the corresponding relationship between the influencing factors and the cable ampacity is obtained, which provides important theoretical basis for the optimization of the cable laying.

Abstract:A heuristic research and fuzzy evaluation fault restoration algorithm for distribution network is proposed to quickly restore power supply for the regions where power supply is interrupted. The algorithm searches power supply paths by finding effective tie-switches and sectionalizing switches, and eliminates improper switch pair according to power flow calculation. During service restoration process, the problem is divided into self-healing restoration, whole-region restoration, sub-region restoration, load-transfer restoration and load shedding restoration. The algorithm takes switch operation times and customer priority into account, and consequently, obtains initial feasible schemes. Fuzzy technique is used to evaluate the schemes from minimal switch operation times, load transfer, feeder margin and maximal voltage drop. Weighted sum of four indices provides a good guideline for choosing the optimal scheme for restoration operation. Calculation results of a certain distribution network show that this algorithm is feasible.

Abstract:Be/Cu/HR-1 stainless steel is bonded at 800℃ by hot pressing under different pressure. Optical microscopy, microhardness tester, scanning electron microscopy （SEM）, auger electron spectroscopy(AES) and X-ray diffraction （XRD）were used to study microstructure and elements distribution of the steel at the bonded area. The relationship of composition and microstructure with pressure is discussed. The results show that pressure will lead to dynamic recrystallization and diffusion creep, and also has effect on the width of diffusion bonding zones, sizes of grain and amounts of intermetallic compound at the diffusion bonding zones. Texture is formed in matrix or at diffusion bonding zones under uniaxial pressure. The intermetallic compound formed along grain boundary is a main reason for causing breakdown of the bonding area. By the reducing holding pressure or time, the intermetallic compound can be reduced and the bonding strength can be improved.

Abstract:In the hot continuous casting billet surface defect inspection system based on machine vision, acquiring a high signal-to-noise image is the key for successful inspection. To solve the disadvantages existing in current machine vision engineering, a new algorithm with improved image definition is presented based on both focus window and CCD target area illumination parameters. It selects a target object from series of hot continuous casting billet surface images, and then acquires the optimum articulation through focus window square gradient algorithm. By recognizing and calculating target’s area loss rate, target area parameter evaluation can be done. The global optimum image quality point is achieved. The algorithm is effective in selecting focus plane and shutter time during hot continuous casting surface imaging process and is of a good practical value. At the same time, the algorithm is useful for image collecting work in other machine vision engineering.

Abstract:Rolled piece deformation is analyzed by FM-BEM in straightening process. Deformation rule of plastic deformation area is analyzed in different straightening force, especially the area of the nodes in neutral axis. Through numerical analysis, it shows that plastic deformation of neutral axis nodes applied 250 kN straightening force is smaller than adjacent nodes. With straightening force increasing, this difference disappeared and formed a relatively flat area in 500 kN. The results obtained by FM-BEM demonstrate that neutral layer has some offset under straightening force. Compression bending amount has relationship with the neutral layer offset and it is one of reasons that compression bending amount is inaccurate. These conclusions are not obtained by FEM.

Abstract:Based on the theory of magnetic dipole, this paper analyzes the forces and moments applied on the particles and established the corresponding equations of motion. It compares these forces respectively in order to reduce the computation time in the numerical simulation. It is found that magnetic force, viscous force and repelling force are stronger than other forces, and translation is the main motion. Therefore the governing equation in the numerical simulation can be simplified. The validity of above dynamic analysis is verified by numerical simulation on the microstructure of magnetorheological fluids.

Abstract:Tianfu Sanhui No.1 mine of Chongqing is located in the convergent extreme of Huayingshan scopulate fold belt, which is an area of in-situ stresses concentration. Coal and gas outburst occurred not only frequently, but also high-intensity, and the working seams are all outburst seams, so the research of its three-dimensional initial in-situ stresses field can put forward the suggestion on the production design of coal mine and the prediction of coal and gas outbursts. Based on the geological materials about Sanhui No.1 mine, this paper developes the 3D FEM model, and uses the elastoplastic finite element method and ANSYS program in numerical simulation of the initial in-situ stresses field. Based on the simulation results, it analyzes the characters of the in-situ stresses of Sanhui No.1 mine and K1 coal seam.

Abstract:This paper developes the physical experimental model for the valley-shaped debris flow, and draw up 15 operating modes in accordance with three sets of particle solids at 0.3~0.8 cm, 0.8~15 cm and 1.5~3.0 cm in diameter and fluid at the solid to liquid (RSL) rate of 0.02, 0.08, 0.16, 0.20 and 0.25. It conducts more than 40 simulations, and obtained 85 000 data using the new test methods such as Fastcam-ultima1024 typed CCD camera, HS200 typed dynamic transducer and multi-channel strain instrument. The experimental results show that the debris flow fluctuation becomes obvious at low RSL, the debris flow surge gradually embodies with the increase of RSL and the initial surge appears ahead of time with the increase of particle diameter. The impact forces of debris flow trend to increase nonlinearly with the increase of RSL and particle diameter, however, the flow speed at the mouth of debris flow valley trend to decrease with RSL increase. The studies may produce some valuable enlightenment in debris flow impact simulations and theory basis for various slurry viscosity and RSL.

Abstract:The paper prepares the intercalated CTMA-bentonite by Na-bentonite cation exchanged with cetyltrimethylammonium and characterizes the product by XRD and IR techniques. The d001 spacing value of CTMA-bentonite is 7.54 larger than that of Na-bentonite at 100% of the cation exchange capacity. The IR spectrum shows that the intensities of OH stretching and bending vibrations of CTMA-bentonite decrease greatly compared with the untreated Na-bentonite. Batch experiments are carried out at 303 K, 323 K and 343 K to obtain the sorption isotherms of methyl orange on CTMA-bentonite. The results show that the sorption isothermal data can be well described by Langmuir and Freundlich model accurately. The dynamical data fit well with pseudo-second-order kinetic model. Thermodynamic parameters such as changes in the free energy (ΔG0), the enthalpy (ΔH0) and the entropy (ΔS0) are also evaluated. The overall adsorption process of methyl orange on CTMA-bentonite is spontaneous, exothermic physisorption. The CTMA-bentonite can be employed as low-cost alternatives to activated carbon in wastewater treatment for the removal of corlor which comes from textile dyes.

Abstract:According to climatic characteristics of the hot summer and cold winter zone, P. R. China and considering the different forms of interior and exterior insulation, different thickness of insulation, different materials of insulation and different forms of the main wall, this paper developed a physical model and a mathematic model, calculated the characteristics of materials and wall construction. It used the software Fluent to analyze thermal performance of different types of walls, to compare the interior and exterior surface temperature. The results of simulation show that under the condition of the same continuous temperature-wave, there are basically irrelative between the external surface average temperature and wall constructions. Compared among those construction with the same index of thermal inertia and heat transmission coefficient, but the different insulation-form, it shows that the exterior insulation has more attenuation and longer delay time than interior insulation ，and the interior surface has less fluctuations of temperature, stronger resistance against wave changes in outdoor temperature and better thermal stability. Under the same main wall material with different insulation materials, it shows that the heat transfer coefficient and thermal inertia can’t be used to comprehensively value the effect of thermal insulation, and the materials with more temperature attenuation have better energy-saving materials performance.

Abstract:The current study on fiber reinforced plastics（FRP） bonded beam are conducted based on the assumption that the bond is very perfect between sheet and beam, and the thickness of adhesive is even. In fact, the thickness of adhesive is not perfectly even and continuous with the limitations of site and technology in construction. The present theory and failure mode about interfacial shear stress can not perfectly show the behaviors of bonded beams. This paper generally establishes the formula of shear stresses at bonded lactation in an FRP bonded beam considering non-linear behavior of concrete under compression and steel rebar, and compares the calculation results of with those of FE. The result shows that they are approximate.

Abstract:It is an effective technology of recycling organic fractions of municipal solid waste as light-weight aggregates (LWA) fired in trefoil rotary kiln. This paper studies the optimum batch formula and optimal calcination conditions of LWA made from municipal solid waste , clay and coal fly ash.The results indicate that: 1)optimum batch formula (dry mixture ration) is 15.38% of BMW，14.85% of clay，69.77% of coal fly ash; 2)optimal calcination conditions are preheating temperature of kiln:500 ℃, sintering temperature:1190 ℃, holding time of sintering temperature: 4 min. The performance testing indicators of aggregate fired under best experimental parameters shows: bulk density is 605 kg/m3, cylinder compressive strength is 3.0 MPa, 1hr water absorption is 11.0%, apparent density is 0.93, all of the targets meet 700 grade light aggregate of GB/17431.2—1998 standards; the results of leaching test are lower than hazardous constituents concentration limits of GB/T 5085.3—2007 standards, LWA is not hazardous to environment.

Abstract:Based on the complex geological environment and hydro-geological conditions in mountainous areas the fuzzy comprehensive evaluation index system of the mine geological environment is constructed. It uses the weak fuzzy consistent matrix and analytic hierarchy process to calculate the weight, which solves the question that traditional AHP is difficult to meet the consistency test. According to the special geological conditions of the mine, it divides the impact of the geological environment into three levels, builts the fuzzy comprehensive evaluation table and determines the membership degree of the influencing factors. Combined with fuzzy comprehensive evaluation method, it developes a second-order fuzzy comprehensive evaluation model of the impact of the mine geological environment. By means of the application of this model to the actual mining, it shows that the evaluation results of the model are highly similar to the actual results of the impacts of landslides, land subsidence and other geological disasters.