Asymptotic analysis of the corner-behaviour of a rigid punch bonded to an elastic substrate

2007 ◽  
Vol 42 (5) ◽  
pp. 415-422
Author(s):  
L Bohórquez ◽  
D. A Hills
Keyword(s):  
Stress Field ◽  
Plastic Zone ◽  
Asymptotic Solution ◽  
Asymptotic Analysis ◽  
Half Plane ◽  
Poisson's Ratio ◽  
Rigid Block ◽  
Rigid Punch ◽  
Oscillatory Behaviour ◽  
Elastic Substrate

The contact between a flat-faced rigid block and an elastic half-plane has been studied, showing that an asymptotic solution correctly captures the stress field adjacent to the contact corners for all values of Poisson's ratio. It is shown that, in practical cases, the plastic zone, which is inevitably present at the contact corners, envelopes the oscillatory behaviour implied locally but is surrounded by an elastic hinterland correctly represented by the asymptote.

Stresses in an Infinite Strip Containing a Semi-Infinite Crack

1966 ◽  
Vol 33 (2) ◽  
pp. 356-362 ◽  
Author(s):  
W. G. Knauss
Keyword(s):  
Fracture Mechanics ◽  
Stress Field ◽  
Asymptotic Solution ◽  
Asymptotic Expansions ◽  
Region Of Interest ◽  
Graphical Form ◽  
Finite Width ◽  
Infinite Strip ◽  
Arbitrary Length ◽  
Laboratory Investigations

Stresses in an infinitely long strip of finite width containing a straight semi-infinite crack have been calculated for the case that the clamped boundaries are displaced normal to the crack. The solution is obtained by the Wiener-Hopf technique. The stresses are given in the form of asymptotic expansions in the immediate crack tip vicinity and for a larger region of interest in graphical form. The effect of prescribing displacements on the boundary close to a crack instead of stresses far away is discussed briefly. Together with an asymptotic solution for a small crack, the result is used to estimate the stress field around a crack of arbitrary length in an infinite strip. The usefulness of this crack geometry in laboratory investigations of fracture mechanics is pointed out.

Validity of the Finite Fracture Mechanics Based Asymptotic Analysis for Predictions of Crack Deflection in Thin Layers of Ceramic Laminates

2014 ◽  
Vol 627 ◽  
pp. 237-240 ◽  
Author(s):  
Oldřich Ševeček ◽  
Dominique Leguillon ◽  
Tomáš Profant ◽  
Michal Kotoul
Keyword(s):  
Potential Energy ◽  
Asymptotic Solution ◽  
Asymptotic Analysis ◽  
Crack Extension ◽  
Crack Deflection ◽  
Thin Layers ◽  
Reference Solution ◽  
Finite Fracture Mechanics ◽  
Higher Order Terms ◽  
Good Agreement

The work studies and compares different approaches suitable for predictions of the crack deflection (bifurcation) in ceramic laminates containing thin layers under high residual stresses and discuss a suitability and limits of using of the asymptotic analysis for such problems. The thickness of the thin compressive layers where the crack deflection occurs is only one order higher than the crack extension lengths considered within the solution. A purely FEM based calculation of the energy and stress conditions, necessary for the crack propagation, serves as the reference solution to the problem. The asymptotic analysis is used after for calculations of the same quantities (especially of energy release rate – ERR). This concept enables semi-analytical calculations of ERR or changes in potential energy induced by the crack extensions of different lengths and directions. Such approach can save a large amount of simulations and time compared with the pure FEM based calculations. It was found that the asymptotic analysis provides a good agreement for investigations of the crack increments enough far from the adjacent interfaces but for longer extensions (of length above 1/5-1/10 of the distance from the interface) starts more significantly to deviate from the correct solution. Involvement of the higher order terms in the asymptotic solution or other improvement of the model is thus advisable.

scholarly journals Effects of small boundary perturbation on the MHD duct flow

2017 ◽  
Vol 44 (1) ◽  
pp. 83-101 ◽  
Author(s):  
Ulavathi Mahabaleshwar ◽  
Igor Pazanin ◽  
Marko Radulovic ◽  
Francisco Suárez-Grau
Keyword(s):  
Magnetic Field ◽  
Asymptotic Solution ◽  
Asymptotic Analysis ◽  
Cross Section ◽  
Transverse Magnetic ◽  
Boundary Perturbation ◽  
Duct Flow ◽  
Rectangular Duct ◽  
Induced Magnetic Field ◽  
Explicit Formulae

In this paper, we investigate the effects of small boundary perturbation on the laminar motion of a conducting fluid in a rectangular duct under applied transverse magnetic field. A small boundary perturbation of magnitude ? is applied on cross-section of the duct. Using the asymptotic analysis with respect to ?, we derive the effective model given by the explicit formulae for the velocity and induced magnetic field. Numerical results are provided confirming that the considered perturbation has nonlocal impact on the asymptotic solution.

scholarly journals A Paradox in Sliding Contact Problems With Friction

2003 ◽  
Vol 72 (3) ◽  
pp. 450-452 ◽  
Author(s):  
G. G. Adams ◽  
J. R. Barber ◽  
M. Ciavarella ◽  
J. R. Rice
Keyword(s):  
Half Plane ◽  
Slip Velocity ◽  
Finite Strain ◽  
Applied Pressure ◽  
Strain Analysis ◽  
Contact Problems ◽  
Rigid Punch ◽  
Flat Punch ◽  
Relative Slip ◽  
Velocity Changes

In problems involving the relative sliding to two bodies, the frictional force is taken to oppose the direction of the local relative slip velocity. For a rigid flat punch sliding over a half-plane at any speed, it is shown that the velocities of the half-plane particles near the edges of the punch seem to grow without limit in the same direction as the punch motion. Thus the local relative slip velocity changes sign. This phenomenon leads to a paradox in friction, in the sense that the assumed direction of sliding used for Coulomb friction is opposite that of the resulting slip velocity in the region sufficiently close to each of the edges of the punch. This paradox is not restricted to the case of a rigid punch, as it is due to the deformations in the half-plane over which the pressure is moving. It would therefore occur for any punch shape and elastic constants (including an elastic wedge) for which the applied pressure, moving along the free surface of the half-plane, is singular. The paradox is resolved by using a finite strain analysis of the kinematics for the rigid punch problem and it is expected that finite strain theory would resolve the paradox for a more general contact problem.

A Diffraction Problem and Crack Propagation

1967 ◽  
Vol 34 (1) ◽  
pp. 100-103 ◽  
Author(s):  
A. Jahanshahi
Keyword(s):  
Exact Solution ◽  
Stress Field ◽  
Crack Propagation ◽  
Elastic Medium ◽  
Half Plane ◽  
Diffraction Problem ◽  
Shear Waves ◽  
Stress Waves ◽  
Plane Crack ◽  
Antiplane Strain

The exact solution to the problem of diffraction of plane harmonic polarized shear waves by a half-plane crack extending under antiplane strain is constructed. The solution is employed to study the nature of the stress field associated with an extending crack in an elastic medium excited by stress waves.

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