Stress field

About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.

In-plane and out-of-plane stress field solutions for V-notches with end holes

Abstract: Closed form expressions of stress distributions for V-notches with end holes and varying opening angles are presented. The solution for the elastic plane problem is obtained by means of the Kolosov-Muskhelishvili approach by using a reduced number of complex terms. The exponents of the potential functions are simple combinations of Williams’ eigenvalues for pointed V-notches in mode I and mode II. The degree of accuracy of the new solution, which is approximate, is found to be very satisfactory for engineering applications. When the V-notch opening angle is equal to zero, the solution matches the keyhole notch solutions already reported in the literature by Neuber (for mode I) and by Kullmer and Radaj (mode I and mode II) and based on the Airy stress function. In parallel, the out-of-plane problem is solved by means of an holomorphic function H(z) where the exponent is still linked to the leading order eigenvalue of the pointed V-notch in mode III. For this loading mode the solution is exact. When the notch opening angle is equal to zero and also the notch root radius tends to zero the solution matches Kullmer’s keyhole notch solution.

Spectral/finite-element calculations of the flow of a Maxwell fluid between eccentric rotating cylinders

Abstract: The steady-state, two-dimensional creeping flow of an Upper-Convected Maxwell fluid between two eccentric cylinders, with the inner one rotating, is computed using a spectral/finite-element method (SFEM). The SFEM is designed to alleviate the numerical oscillations caused by excessive dispersion error in previous finite-element calculations and to resolve the stress boundary-layers that exist for high elasticity, as measured by the Deborah number De . Calculations for cylinders with low eccentricity (ϵ = 0.1) converged to oscillation-free solutions for De ≈ 90, extending the domain of convergence over traditional finite-element methods by a factor of thirty. The results are confirmed by extensive refinement of the discretization. At high De , steep radial boundary layers form in the stress, which match closely with those predicted by asymptotic analysis. Calculations at higher eccentricity require extreme refinement of the discretization to resolve the variations in the stress field in both the radial and azimuthal directions associated with the existence of the recirculation region. Results for ϵ = 0.4 show that the recirculation region present for the Newtonian fluid ( De = 0) shrinks and then grows with increasing De . Calculations for ϵ = 0.4 are terminated by a limit point near DeL ≈ 7.24 for the finest discretization used. The Fourier series approximations are not convergent for this mesh, so the limit point must be considered to be an artifact of the discretization.

Unusual shallow normal‐faulting earthquake sequence in compressional northeast Japan activated after the 2011 off the Pacific coast of Tohoku earthquake

Abstract: [1] After the occurrence of the 2011 Mw9.0 off the Pacific coast of Tohoku earthquake, an unusual shallow normal-faulting earthquake sequence occurred near the Pacific coast at the Ibaraki-Fukushima prefectural border. We have investigated why normal-faulting earthquakes were activated in northeast (NE) Japan, which is otherwise characterized by E–W compression. We computed the stress changes associated with the mainshock on the basis of a finite fault slip model, which showed that the amount of additional E–W tensional stresses in the study area was up to 1 MPa, which might be too small to generate normal-faulting earthquakes in the pre-shock compressional stress regime. We thus determined focal mechanisms of microearthquakes that occurred in the area before the mainshock, which indicated that the pre-shock stress field in the area showed a normal-faulting stress regime in contrast to the overall reverse-faulting regime in NE Japan. We concluded that the 2011 Tohoku earthquake triggered the normal-faulting earthquake sequence in a limited area in combination with a locally formed pre-shock normal-faulting stress regime. We also explored possible mechanisms for localization of a normal-faulting stress field at the Ibaraki-Fukushima prefectural border.