Advanced Materials Research Vols. 295-297

Abstract: A vibration wave generated actively by hydraulic vibration exciter was studied, and an experimental system based on the theory of water hammer was designed. The new developed vibration exciter is driven by the motor whose rotary speed can be adjusted by frequency converter, by means of which transient pulsating flow is generated regularly. Consequently the piston of hydraulic cylinder is driven periodically with the rotation of vibration exciter. Furthermore, mathematical model was established by the method of characteristics and computer code was developed to calculate numerical solution. The simulation results show that there are different flow velocities distributed at every cross section along the pipe. Measured data is basically consistent with the numerical simulation, which indicates that the vibration parameters of hydraulic cylinder can be controlled effectively.

Abstract: A one degree of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction is built firstly, the numerical method is taken to study the impacts of dynamics parameters on self-excited vibration. The calculation result shows that Along with the variation of system dynamics parameters such as initial velocity or normal pressure the self-excite vibration has the weakened trend or the enhanced trend, so the self-excite vibration could be controled through the control of dynamics parameters.

Abstract: In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

Abstract: A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the numerical method is taken to study the impacts of damping on automobile brake groan. The calculation result shows that the variation of damping coefficient and has different influence on automobile brake groan. and all have A critical value, when damping coefficient greater or less than the critical value the brake disk and pad possess the different vibration state respectively.

Abstract: In photovoltaic industry during wafer sawing significant amount of solar grade silicon is getting lost into sawing slurry. In the present paper, potential approach and routes for recycling and reuse of silicon wafer sawing slurry are explored. Various techniques were used including distillation, heavy liquid separation, acid leaching and high temperature processing. After distillation, the polyethylene glycol (PEG) can be separated and reused as lubricant. By dissolving silicon at high temperatures from the kerf into a clean molten pool of silicon metal or scrap, or into an alloying metal like Cu, SiC can also be separated and recovered. Depending on the impurity level, solar grade silicon can be finally produced from this waste stream in combination with necessary refining treatment for the applications in the PV industry. Furthermore, converting the kerf into SiC or Si₃N₄ particles as technical ceramic products is also explored. It is expected that the present research can pave a way to develop a total recycling route for an optimum use of this resource, and to minimize the environmental risk of the waste disposal.

Abstract: Extension theory is the theoretical foundation of artificial intelligence and widely used in many fields such as optimal estimation and predictive control, manufacturing and design science. Dependent function is the core of extension set. According to the fact that decision-makers have different preferences for characteristics of basic-element, we defined the weighted distance between the point and the field within the multi-dimensional space, and constructed the location value and the elementary dependent function that has one variable and some dimensions based on the finite nested field. Some properties are also discussed. The proposed functions allow extension theory with a broader scope.

Abstract: luster is an important surface property of the fabric material. Even if the same weave and color of the fabrics, the different appearances could be exhibited when the fabrics are made from different materials. In this paper, we analyzed the different characteristics of pictures taken from real yarns made from different fibers (mainly cotton, bast, silk and wool), and extracted the brightness distribution properties of the pictures. For the yarn luster is highly dependent on the material, we used the method of Shepard interpolation to fit the brightness characteristics of the yarns, so as to set up the specific fitting function. Such fitting function was used to simulate the real texture of the yarn. At the same time, we use the factor of elliptic lighting model to revise the yarn brightness in the fabric. Experiment results show that the method deduced in this paper could exhibit the different appearances of the yarns, and obtain a relative real simulation of the fabric.

Abstract: Block forming machine, as a kind of automatic equipments, can quickly compact blocks. Higher-order spectrum analysis emerges as a new effective method in signal processing, which can describe nonlinear coupling, restrain Gaussian noise and reserve phase components. In the paper, a hydraulic exciter applying to block forming machine will be introduced. Then block forming machine’s random vibration signals during the compacting process would be collected, in order to make use of the sample data to build up a time series autoregressive model and bispectrum of three-order accumulation, to analyze AR bispectrum characteristics of the machine’s vibrate signals under different work conditions.

Abstract: To study the deformation and fracture form of double-deck metal cylindrical tube under inside-explosive loading，the numerical simulation of the deformation and fracture process of double-deck metal cylindrical tube under inside-explosive loading of TNT was performed by LS-DYNA, and the fragment number and mass statistics software code is developed. The results showed that, with different length of TNT and detonating position the fragment number and mass is greatly different . The result can be a consult to some practicalities like the cannonball exploded in the gun barrel during shoot.

Abstract: The finite element model of grinding wheel carriage on glass edging machine was established, some key mechanical joints such as ball lead screw pair, linear rolling guide pair and lead screw bearing were simulated by combin14 spring-damp unit. The mode analysis was finished by ANSYS software, the frontal 4 modes and natural frequencies indicated that the weak part of grinding wheel carriage vibration was lead screw and assembly board of sliding block. The natural frequency and dynamic behavior of grinding wheel carriage will be improved by increasing diameter of lead screw and thickness of assembly board of sliding block, preloading lead screw bearing and ball lead screw pair, using middle or heavy preload linear rolling guide. The research result is very important for the design of large scale vertical glass edging machine.