scholarly journals An upper-bound analytical model of blow-out for a shallow tunnel in sand considering the partial failure within the face

2019 ◽  
Vol 91 ◽  
pp. 102989 ◽  
Author(s):  
Pengfei Li ◽  
Keyi Chen ◽  
Fan Wang ◽  
Zheng Li
Keyword(s):  
Analytical Model ◽  
Upper Bound ◽  
Shallow Tunnel ◽  
Partial Failure ◽  
The Face

Reducing Wear in an Electromagnetic Clutch

1968 ◽  
Vol 90 (2) ◽  
pp. 308-316
Author(s):  
R. Kilburn
Keyword(s):  
Differential Equations ◽  
Analytical Model ◽  
Elastic Constants ◽  
Friction Material ◽  
Metal Rings ◽  
Friction Disk ◽  
The Face ◽  
Electromagnetic Clutch ◽  
Residual Magnetism

An analytical model of an electromagnetically operated friction-disk clutch is constructed in order to determine the wear on the clutch face. The face consists of two materials—metal rings and friction material. The pertinent differential equations, derived in the Appendexes, are solved numerically. The effects of varying such parameters as hardness, residual magnetism, and elastic constants are studied.

scholarly journals Upper Bound Solution for the Face Stability of Shield Tunnel below the Water Table

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xilin Lu ◽  
Haoran Wang ◽  
Maosong Huang
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Fe Simulation ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Seepage Force ◽  
Tunnel Face ◽  
Face Stability ◽  
The Face ◽  
Upper Bound Limit Analysis

By FE simulation with Mohr-Coulomb perfect elastoplasticity model, the relationship between the support pressure and displacement of the shield tunnel face was obtained. According to the plastic strain distribution at collapse state, an appropriate failure mechanism was proposed for upper bound limit analysis, and the formula to calculate the limit support pressure was deduced. The limit support pressure was rearranged to be the summation of soil cohesionc, surcharge loadq, and soil gravityγmultiplied by their corresponding coefficientsNc,Nq, andNγ, and parametric studies were carried out on these coefficients. In order to consider the influence of seepage on the face stability, the pore water pressure distribution and the seepage force on the tunnel face were obtained by FE simulation. After adding the power of seepage force into the equation of the upper bound limit analysis, the total limit support pressure for stabilizing the tunnel face under seepage condition was obtained. The total limit support pressure was shown to increase almost linearly with the water table.

scholarly journals Almost simplicial polytopes: the lower and upper bound theorems

2020 ◽  
Vol DMTCS Proceedings, 28th... ◽  
Author(s):  
Eran Nevo ◽  
Guillermo Pineda-Villavicencio ◽  
Julien Ugon ◽  
David Yost
Keyword(s):  
Lower Bound ◽  
Upper Bound ◽  
Upper Bounds ◽  
Lower And Upper Bounds ◽  
Upper Bound Theorem ◽  
Simplicial Polytopes ◽  
Full Version ◽  
The Face ◽  
International Audience ◽  
Bound Theorem

International audience this is an extended abstract of the full version. We study n-vertex d-dimensional polytopes with at most one nonsimplex facet with, say, d + s vertices, called almost simplicial polytopes. We provide tight lower and upper bounds for the face numbers of these polytopes as functions of d, n and s, thus generalizing the classical Lower Bound Theorem by Barnette and Upper Bound Theorem by McMullen, which treat the case s = 0. We characterize the minimizers and provide examples of maximizers, for any d.

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