Shearing Stress Model of Damage Bolt in Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 1761-1767
Author(s):  
Xiao Hua Xi ◽  
Shuan Cheng Gu
Keyword(s):  
Shear Stress ◽  
Axial Force ◽  
Surrounding Rock ◽  
Stress Model ◽  
Calculation Formula ◽  
Shearing Stress ◽  
Pullout Load ◽  
Fully Grouted Bolt ◽  
Grouted Bolt ◽  
Force Calculation

When bolt is damaged, character of stress is different from character of shear stress integrated bolt. Firstly, Based on the displacement formula of the tunnel surrounding rock，the shear stress and axial force calculation formula of integrated bolt are educed. Subsequence, based on the BOUSSINESG formula of displacement, models on fully grouted bolt shear stress and axial force of uniform rock are educed under pullout load. Consequently, the author deduces shear stress model of bolt damage (completely void of bolt and grouting), combining modes on shear stress and axial force of integrated bolt and shear stress model of bolt under pullout load..

Research on the Reinforcement Mechanism of Stretched Rock Bolt and Analyzing of the Impact Parameters

2013 ◽  
Vol 690-693 ◽  
pp. 2016-2021 ◽  
Author(s):  
Xun Guo Zhu
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Axial Force ◽  
Rock Bolt ◽  
Mining Engineering ◽  
Long Time ◽  
Fully Grouted Bolt ◽  
Effective Reinforcement ◽  
Grouted Bolt ◽  
The Impact

The rock bolt has been widely used as an effective reinforcement in civil and mining engineering for a long time. However, the anchored mechanism of it is not well understood. This paper obtained the expression of the shear stress and axial force of stretched fully grouted rock bolt base on previous working, and detailed analysis the influence parameters of stress distribution. It is considered the anchored effect is influenced by some factors. Augmenting diameter of rock bolt, increasing the pre-stress magnitude and improving the strength of grout may all improve the anchored effect of rock bolt. As the rock character and the grout property are similar, the rock bolt anchored effect is optimal. There is a stress concentrated phenomena at the front of rock bolt. It is shown that the distribution of shear stress and axial force are not even distribution and exponentially attenuated along a fully grouted bolt.

scholarly journals Calculation Formula Optimization and Effect of Ring Clearance on Axial Force of Multistage Pump

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chuan Wang ◽  
Weidong Shi ◽  
Li Zhang
Keyword(s):  
Axial Force ◽  
Angular Speed ◽  
Calculation Formula ◽  
Accurate Calculation ◽  
Pump Chamber ◽  
Static Pressure Distribution ◽  
Simulation And Experiment ◽  
Computational Fluid Dynamics Cfd ◽  
Multistage Pump ◽  
Force Calculation

Since overlarge axial force can damage the pump, accurate calculation formula of axial force on pump is very significant. The traditional formula is based on the assumption that the leakage amount of the pump is zero and the angular speed of fluid in the pump chamber rotates at half the impeller rotation’s angular speed. In order to propose an accurate calculation formula, the whole flow fields of multistage pumps with three different ring clearances were calculated by using Computational Fluid Dynamics (CFD). The results indicate that the axial force on first-stage impeller is larger than that on the second. Along with the change of ring clearance, the static pressure distribution on the shroud of impeller changes at the same time, which leads to the value change of axial force. Meanwhile, angular speed of the fluid in the pump chamber is changing. Therefore, this research works out the reason why the error of traditional axial force calculation is large when the amount of leakage is relatively high. At last, an accurate calculation formula of axial force on pump is obtained through the verification of numerical simulation and experiment.

scholarly journals Simulation of the Load Evolution of an Anchoring System under a Blasting Impulse Load Using FLAC3D

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xigui Zheng ◽  
Jinbo Hua ◽  
Nong Zhang ◽  
Xiaowei Feng ◽  
Lei Zhang
Keyword(s):  
Shear Stress ◽  
Dynamic Response ◽  
Axial Force ◽  
Mechanical Characteristics ◽  
Oscillation Amplitude ◽  
Anchoring System ◽  
Impulse Load ◽  
The Stability ◽  
Calculation Software ◽  
Dynamic Perturbation

A limitation in research on bolt anchoring is the unknown relationship between dynamic perturbation and mechanical characteristics. This paper divides dynamic impulse loads into engineering loads and blasting loads and then employs numerical calculation software FLAC3Dto analyze the stability of an anchoring system perturbed by an impulse load. The evolution of the dynamic response of the axial force/shear stress in the anchoring system is thus obtained. It is revealed that the corners and middle of the anchoring system are strongly affected by the dynamic load, and the dynamic response of shear stress is distinctly stronger than that of the axial force in the anchoring system. Additionally, the perturbation of the impulse load reduces stress in the anchored rock mass and induces repeated tension and loosening of the rods in the anchoring system, thus reducing the stability of the anchoring system. The oscillation amplitude of the axial force in the anchored segment is mitigated far more than that in the free segment, demonstrating that extended/full-length anchoring is extremely stable and surpasses simple anchors with free ends.

Mathematical analysis of Phan-Thien–Tanner fluid model for blood in arteries

2015 ◽  
Vol 08 (05) ◽  
pp. 1550064
Author(s):  
Noreen Sher Akbar ◽  
S. Nadeem
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Fluid Model ◽  
Shearing Stress ◽  
Small Arteries ◽  
Tapered Artery ◽  
Impedance Wall ◽  
Flow Through ◽  
Parameters Of Interest

In the present paper, we have studied the blood flow through tapered artery with a stenosis. The non-Newtonian nature of blood in small arteries is analyzed mathematically by considering the blood as Phan-Thien–Tanner fluid. The representation for the blood flow is through an axially non-symmetrical but radially symmetric stenosis. Symmetry of the distribution of the wall shearing stress and resistive impedance and their growth with the developing stenosis is another important feature of our analysis. Exact solutions have been evaluated for velocity, resistance impedance, wall shear stress and shearing stress at the stenosis throat. The graphical results of different type of tapered arteries (i.e. converging tapering, diverging tapering, non-tapered artery) have been examined for different parameters of interest.

scholarly journals Spectrum Analysis and Optimization of the Axial Magnetic Gear with Halbach Permanent Magnet Arrays

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2003
Author(s):  
Fang Hu ◽  
Yilan Zhou ◽  
Hesong Cui ◽  
Xiao Liu
Keyword(s):  
Permanent Magnet ◽  
Axial Force ◽  
Spectrum Analysis ◽  
Parametric Analysis ◽  
Air Gap ◽  
Torque Density ◽  
Output Torque ◽  
Magnetic Gear ◽  
The Difference ◽  
Force Calculation

In order to study the contribution of each harmonic to the output torque and axial torque of the axial magnetic gear with Halbach permanent magnet arrays (HAMG), torque and axial force calculation formulas of the HAMG are proposed based on the air-gap flux density distribution of the HAMG. Because of the difference of the air-gap flux densities at different radii, two simplified torque and axial force calculation formulas are proposed and compared. To improve the torque capability of the HAMG, parametric analysis of eight dimensional parameters is firstly conducted. By parametric analysis, six parameters such as the inner radius have been found to have obvious impact on the output torque and output torque density of the HAMG. The optimization using Maxwell software is then executed for maximizing the output torque density of the HAMG. The output torque density of the optimized HAMG is improved from 78.1 kNm/m3 to 93.3 kNm/m3 with an increase of 19%. Furthermore, spectrum analysis is also presented to illustrate the significant output torque improvement based on the torque calculation formulas.

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