Papers by Keyword: Slip

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Authors: Da Peng Xing, Jia Li, Da Qiang Qiu
Abstract: Critical clearing time index is one of the indices to assess transient voltage stability. At present it is mainly calculated based on the instantaneous value after transient voltage instability or the steady state valueafer fault clearing time. So a new method to estimate the critical clearing time is presented which is correspongding to the induction motor minimum slipvalue in the fault. It can forecasttransient voltage instability,and has higher precision comparing whithquik criterion and analytical method. The simulation results of IEEE 30-bus system verify the effectiveness of the stated method. .CLC number: TM 73 Document code: A Article ID: 000-3673(2013)00-0000-00
Authors: M.H. Oladeinde, John A. Akpobi
Abstract: A mathematical model for the hydrodynamic lubrication of finite slider bearings with velocity slip and couple stress lubricants is presented. A numerical solution for the mathematical model using finite element scheme is obtained using four node linearly interpolated quadrilateral elements. Stiffness integrals obtained from the weak form of the governing equations were solved using Gauss Quadrature to obtain a finite number of stiffness matrices. The global system of equations was obtained for the bearing and solved using Gauss Seidel iterative scheme. The converged pressure solution was used to obtain the load capacity of the bearing. Numerical experiments reveal the existence of an optimum velocity slip for which maximum benefit is obtained for the slider bearing in terms of bearing load. Increase in the slip parameter beyond this optimum value was shown not to augment the bearing load. Computations put forth also affirm that the bearing load is augmented with increase in couple stress parameter. An optimal film thickness ratio was also obtained for which load capacity is maximized with or without the application of slip to the bearing surfaces.
Authors: Bo Min Kim, Won Yung Lee, Eung Hyuk Lee
Abstract: A slip controller that can move against the off-track and control excursion caused by slips while driving a motorized wheelchair is proposed. Detecting slips in a motorized wheelchair is to detect states of the motorized wheelchair and its motors in a traveling condition. For carrying it, slip ratios are calculated using a slip detection algorithm based on the information obtained from the six-axis IMU sensor and the encoders, which are connected to both left and right motors. The calculated slip ratios are used as control variables for improving the safety in a motorized wheelchair. In the experiment of the slip controller proposed in this study, slips are verified in a proposed track. Also, it is verified that the maximum slip ratio section is determined while turning left or right.
Authors: Yin Zhang, Yoshiyuki Yokogawa, Tetsuya Kameyama
Abstract: There is a clinical need for synthetic scaffolds that will promote bone regeneration. Important factors include obtaining an optimal porosity and size of interconnecting macropores whilst maintaining scaffold mechanical strength, enabling complete penetration of cells and nutrients throughout the scaffold, preventing the formation of necrotic tissue in the centre of the scaffold. To address this we investigated flexural strength of bimodal porous apatite ceramics prepared using apatite slurry and its slurry synthesis was studied. Slips with different contents of HAp (K-HAp and T-HAp) and deflocculant were prepared by milling in a pot mill. The viscosity of slurries made of commercial T-HAp powder showed a drop after 3 hours’ milling, but the viscosity of slurry with high solid content of k-HAp and 2.0 wt% deflocculant increased with an increase of milling time after 2 hours’ milling. The porosity and flexural strength of the porous HAp prepared by heating the foam dipped in K-HAp slip with 2.0 wt% of deflocculant and 0.5wt% of foaming regent heated at 1200°C were 62.4 % and 14.7 MPa, and those in T-HAp were 59.7 % and 15.2 MPa with 1.5 wt% of deflocculant and 0.5wt% of foaming regent heated at 1200°C.
Authors: A. Jaworski, Sreeramamurthy Ankem
Abstract: In recent years, significant advances have been made in regard to the creep deformation behavior of two phase titanium alloys. It has been shown that the creep resistance depends on a number of factors, including the shape of the component phases, the strength difference between the phases, and the stability of the beta phase. For example, in two-phase materials with a similar volume fraction and morphology of phases, if the beta phase is less stable, then the creep resistance is lower. These developments will be reviewed and the reasons for such effects will be suggested.
Authors: Takuya Uehara
Abstract: Molecular dynamics simulations were carried out to investigate the plastic deformation mechanism of fcc crystalline materials using the conventional Lennard-Jones potential. An fcc structure with square cross-section was prepared, and a tensile load was applied in the longitudinal direction. A weak potential was assigned to a specific (111) plane to induce a slip on the specified plane. Accordingly, a slip was initiated in the weak plane following an elastic deformation. The step-by-step motion of the atoms on the slip plane was studied, and a detailed trajectory is presented. The slip then expanded to other planes, and plastic deformation progressed in the whole model. The weak plane was also set as (110) or (100) plane, where different deformation modes were observed: not only slip but also gradual distortion or brittle fracture occurred.
Authors: Meng Chen, Pin Wu Guan
Abstract: Prestressing spiral groove tendon is a new sort prestressing tendon, its characteristic value of tensile yield strength fyk=1000MPa. Firstly, the yield strength, ultimate tensile strength, elastic modulus and elongation are all tested. According to 68 pullout tests, the bond-anchoring curves and failure modes have been studied, and the effects of concrete strength, diameter, anchoring length, thickness of concrete cover and stirrup ratio have been all analyzed. Finally, the equation for ultimate bond-anchoring strength has been suggested by statistical regression, and the test results are in good agreement with values of the suggested equation.
Authors: Kounosuke Nakamura, Hiromoto Kitahara, Shinji Ando
Abstract: {10 2} twin is common in pure hcp metals. In this study, initiation and development of {10 2} twin in hcp metal was simulated by molecular dynamics (MD) method. Two types of model crystals were stretched along the y-axis by applying displacement of 0.005a (a is lattice constant of the basal plane) every 1000 MD steps and relaxed atoms by molecular dynamics method. The Y-boundary of the model was applied fixed boundary condition and the X and the Z-boundary were free boundary condition. The Lennard-Jones type interatomic potential was employed in this simulation. In the single crystal, {10 1} pyramidal slip initiated at the crack tip and the pyramidal slip was stopped at Y-boundary atoms. After that, a {10 2} twin was initiated at a front of the slip. With increasing external strain, the twin grew with increasing external strain. In the bi-crystal, {10 0} prismatic slip occurred at the crack tip in Crystal 1 and a-dislocation of the slip stopped at a grain boundary between the Crystal 1 and 2. With increasing applied strain, {10 2} twin was initiated in the Crystal 2 at the grain boundary. From the simulation results, the ‘shuffling’ process of twin deformation was estimated.
Authors: Wan Heng He, Qing Hua Gu, Ying Chen Ma, Xin Hua Ni, Xiang Feng Meng
Abstract: Composite beam takes full advantage of mechanical properties of brittle and ductile materials elements. The key point is to rely on the shear connectors ensure overall coordination of composite beam, so as to achieve the effect of flexural component. The crack in composite beam caused by brittle materials elements is not negligible. We obtained the slip of shear connectors with the second order precision under the conditions that there are cracks in the brittle material elements, and the ultimate moment is obtained too.
Authors: Mao Jia Cai, Yin Ping Cao, Xing Wang, Yi Hua Dou
Abstract: The HTHP completion packers slip is a key element in ensuring the reliability of the packer. It plays an important part in supporting and locking the seal bore after anchoring in the casing wall. When the slip in touch with the casing, the interaction force between them occurs, and the supporting function of slip relies mainly on the interaction with the casing. This article analyzes the depth of slip into the casing based on the theory analysis and ANSYS finite element analysis. It approves that the biting depth of the slip increases with the load, and with the increase of tooth number, biting depth is gradually reduced. At last, we get the biting depth of the slip when the packer seated, which is 0.5mm~0.7mm. Besides this, we also analyze the VONMISES stress of the slip and the casing system and find that with the increase of tooth number the tooth stress gradually reduced, and that the slip biting depth and tooth stress gradually increase with the load.
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