This study was focused on the theoretical modeling and numerical investigation about the dynamic and static stiffness of coupled double-rotor spindle system of high speed grinder. The moment balance and the transition matrix, the state vector, field matrix of spindle system of high speed grinder were analyzed and deduced. The theoretical models about dynamic and static stiffness were established using the transfer matrix method. The numerical results showed that increased rigidity of front bearing significantly increased static and dynamic rigidity of spindle end and the rigidity of front bearing increased, dynamic rigidity increased more significantly than static rigidity. Furthermore, it can be conclued that increased overhang length reduced dynamic and static rigidity of spindle end at an increasingly slower rate and the span of bearing increased, static and dynamic rigidities of spindle end were reduced
This article evaluates the seismic control effect of vertical irregularity factors for RC frame structures using the Monte Carlo simulation method. Typical 5-and 10-story frame structures with different irregularities of strength or stiffness are assessed. The upper-and lower-bound probabilities of failure exceeding the limit state are studied. The results indicate that the exceeding probability increases as the vertical irregularity factor decreases. The upper-bound probability of failure, which is sensitive to the vertical irregularities and is an effective indicator for evaluating the performance control parameter, is significantly larger compared with the lower-bound probability of failure. A minimum strength and stiffness irregularity factor of 0.7 can serve as the seismic control limit.
On the base of the obtained materials and considering the factors of composition features, dynamic mechanism and deformation-motion characteristics, the three-dimension numerical simulation model is generated. And the parameters of Young module, passion ratio and shear strength are obtained. Then the calculation conditions are extracted from the combination of the inducible factors and the displacement features. After that, the deformation failure are simulated by the FLAC3D code, and the results are compared to the monitoring data. The results indicate that the influence of the water impoundment on the stability of the landslide is small, the water descending is large. For the front part monitoring points, the amounts and the curve shapes of the numerical calculation results are accord with the practical ones, but for the monitoring point in back there are only the similarities in the curve shapes, and the amounts are a little smaller.
Taking a landslide in the three gorges reservoir area as an example and considering the seepage field in different time periods with rise and fall of reservoir water level of the eight conditions, we use GEO-STUDIO / SEEP module to establish a seepage model and to calculate the distribution of seepage. The results showed that: the groundwater saturation line appears in the back-phenomenon during a certain range of slope in the rising water level, saturation line was concave shape, and with the rate of increase in water level increased and that concavity gradually increase; the groundwater saturation line appears in the downstream phenomenon during a certain range of slope in the drawdown water level, saturation line was convex shape, and with the rate of decline in water level increased and that convexity increases. The effective simulation studies of the greatly and cyclical fluctuations of water level under the slope seepage field has a certain reference meaning to the landslide control in the reservoir water level fluctuations about reservoir bank landslide.
This study was focused on the theoretical modeling and numerical investigation about the dynamic and static stiffness of spindle system of high speed grinder. The moment balance and the transition matrix, the state vector, field matrix of spindle system of high speed grinder were analyzed and deduced. The theoretical models about dynamic and static stiffness were established using the transfer matrix method. The numerical results showed that increas of the preload could result in the improvement of static stiffness of spindle end within the range of its working speed; the reduction of front overhang length would improve the stiffness of spindle end, as well as the dynamic stiffness of spindle at the working speed; the stiffness of spindle end decreased with the increase of speed with different bearing spans within the range of working speed of spindle.
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