Applied Mechanics and Materials Vols. 602-605

Abstract: This paper results the tension of putting thread machine by analyzing and calculating the polarization grid technology requirements; uses CATIA and ANSYS Workbench to build a three-dimensional solid model and analyze the static characteristics and provides a reliable reference In order to improve the structure of put thread machine.

Abstract: Balancing with the influence coefficient method can eliminate rotor unbalance effectively and briefly which usually causes mechanical vibration. But the accuracy of this method is susceptible to operating condition and the structure of mechanical equipments will leads to unstable equilibrium outcomes. The theoretical study of the influence coefficient balancing method can find that the solution process of balancing weight does not involve the mechanical nature of unbalance vibration, and therefore it will be subject to greater interference of equation’s ill-conditioned characteristics. By introducing the modal superposition, vibration mode function can be linked with the influence coefficients to establish the relationship between counter weight location parameters and ill-conditioned equations. The simulation results of multiple-blade rotor shows that positions of balancing weight will exert great influence on ill-conditioned characteristics. So the position parameters should be chosen in front of balancing service reasonably.

Abstract: This paper presents the 3D dynamic crack growth simulation of unreinforced baked brick shear wall by using particle discretization scheme finite element method (PDS-FEM), which is efficient and capable of computing bifurcation/branching in cracking. The technology of fast modelling of bricks and cements by applying VB script in AUTOCAD is illustrated briefly. The shear wall including mortar joints is modelled in detail. The model parameters are calibrated by using standard static tests. Since the computation cost is high in structural level fracture analysis, parallel computation technology is employed. Finally, with two-phase failure criterion of mortar under multi-dimension stress state, the performance of low and high loading speed is compared. The numerical results verify the availability of dynamic fracture analysis of masonry structure by using PDS-FEM.

Abstract: In the process of DF system machining the small diameter deep hole, the working parameters of negative pressure device has a great influence, including injection coefficient, chip removal of cross-sectional area ratio, discharge pressure, negative pressure number, etc. Injection coefficient has the non-linear proportional relationship with chip removal of cross-sectional area ratio, with the increasing incidence of negative pressure discharge pressure increases, as well as, increasing negative pressure number to improve chip removal have a good effect. Movement patterns of cutting fluid is simulated, energy loss of cutting fluid in the flow is studied, finding curved edge nozzle has better negative effects than straight edge nozzle. The effect of negative pressure pumping crumbs is analyzed, the injection process of negative pressure device is simulated, and the form of the fluid motion in negative pressure nozzle is got based on Fluent, which have a good guide for the actual production and machining.

Abstract: The accuracy of safety analysis can be guaranteed when the torsional vibration model is adjusted online according to the inherent characteristics of the torsional vibration of the shafting. Torsional stiffness of model is set as the object for adjustment. The sensitivity of the natural frequency of torsional vibration model to structure parameters is analyzed and the sensitivity of the natural frequency of torsional vibration model to torsional stiffness is calculated. According to the difference between the natural frequency of torsional vibration which is get from actual shafting and the natural frequency of torsional vibration which is calculated by torsional vibration model, the adaptive adjustment of the torsional stiffness of mode is solved by using the method of Taylor expansion which ignore two times or more correction. The logic structure of the adaptive process of torsional vibration model is designed and the online adaptive function of torsional vibration model is implemented in the torsional vibration safety and analysis system. The torsional vibration modelof 1000WM turbogenerator is used as an example and the accuracy of the method is verified.

Abstract: The research program of crosswind aerodynamics was formulated with yaw model test of the relative motion principle for a domestic heavy duty truck. This approach was applied separately wind tunnel test and numerical simulation, to obtain six aerodynamic coefficients of the corresponding heavy duty truck model, and the numerical simulation method was proved to be true by comparative analysis. The conclusions of aerodynamic characteristics got from simulation could provide a useful reference to reduce the impact on crosswind handling stability and the fuel consumption of the heavy duty truck.

Abstract: using finite element method to study the stress variation of cylindrical specimen during the cooling process of quenching, through the establishment of the computer models of mechanical property and thermal property, and using computer to perform the numerical simulation of temperature environment and structure in the process of quenching, simplify the operation process on one hand, and facilitate the analyses of complicated nonlinear problems on the other hand. The outcome according to the stress variation of the outside surface of cylinder indicates that during the process of quenching, the cooling speed of the inner surface of cylinder is much slower than that of the outer surface, leading to the reverse between the center stress and the outer surface stress of hollow cylinder, which finally turns into internal stress distribution of structural stress type.

Abstract: In continuous casting industry, scale cutting is used to control the current domestic company’s adoption: "to touch the ball type", "friction roller number", "the camera imaging control type" and "the infrared switch control type" etc. Their cost and their accuracy are different. Inverter is the product of perfect combination of power electronic technology and computer technology. Inverter speed control precision is high, speed range is wide and energy saving effect is obvious, which is widely used in the motor system. Inverter changes the motor speed by changing the frequency. There are three ways to change the frequency (or change the frequency of the signal): PU panel, external terminal and communication cables.

Abstract: Mill housing vibration influents the strip thickness fluctuation. The longitudinal deformation of rolling mill will directly affect plate thickness difference. The longitudinal deformation should be reduced , improving the mill stiffness. Hot rolling mill is seen as is as subject investigated . The improved GA is used to optimize the mill housing parameters. The optimal result is analyzed. The housing stiffness improves. Low order natural frequency improves after optimization, avoiding resonance and improving the housing dynamic stability.

Abstract: According to the production data of a rolling H-beam factory, the FE model of hot continuous rolling process of H-beam is built. With the FEM software of DEFORM-3D, the continuous rolling of H-beam was simulated. On base of simulation result, the metal flow and deformation law are discussed. Because of the flange and web is deformed in the different deformation zone, the metal flow law of flange and web is complex, especially the metal of the conjunction of flange and web. In this paper, the metal flow of large-sized H-beam in finishing rolling process is analyzed.