A controlled crack growth was achieved in single edge—cracked specimens made of a high—molecular weight PNNA by regulating the cross— head speed of loading of the specimens by a computer—driven testing device. The crosshead speeds used during the tests were varied between v =1x107m/s and 1X1O5m/s. 5 It was shown that in this area of very slow quasi—static loading of brittle plexiglas specimens ...

In this paper, elasto-plastic analysis of an edge crack has been performed using element free Galerkin method. A model problem has been solved in plane stress condition under mode-I loading. A system of nonlinear equations has been obtained by using incremental theory of plasticity, and the equations are solved by assuming piecewise linear approximation. A code has been written in Matlab for el...

Ultrahigh molecular weight polyethylene (UHMWPE) has remained the primary polymer used in hip, knee and shoulder replacements for over 50 years. Recent case studies have demonstrated that catastrophic fatigue fracture of the polymer can severely limit device lifetime and are often associated with stress concentration (notches) integrated into the design. This study evaluates the influence of no...

This paper proposes a reliable and cost-effective two-phase methodology to predict crack propagation life in generic two-dimensional (2D) structural components. First, the usually curved fatigue crack path and its stress-intensity factors are calculated at small crack increments in a specialized finite-element software, using automatic remeshing algorithms, special crack tip elements and approp...

Nomenclature A k , a k Fourier series coefficients, d mean difference between theoretical and experimental stress values, i square root of –1, m mapping function shape descriptor, r, θ polar coordinates in the mapping plane, s standard deviation in the difference between stress values, t distance from the crack tip, x, y Cartesian coordinates in the physical plane, z complex coordinate in the p...

Fatigue crack growth was investigated in a 001 1⁄2 oriented single crystal specimen, made of a Ni-based superalloy, Haynes 230. Crack propagation was characterized with digital image correlation: crack closure, measured by analyzing the relative displacements of crack flanks, showed closure levels much lower than polycrystal alloys. Reversed plastic zones were calculated from regressed stress i...

ABSTRACT: This study provides an analysis of the influence of underground CO2 storage on the effective stress field in a representative geological formation. Large scale finite element models are used to describe the injection process. For high injection rates, different material degradation mechanisms may be activated depending on initial conditions. The case of rock fracturing due to tensile ...

The accuracy of the Extended Finite Element Method (XFEM) in solving problems of straining plate with central crack is analyzed. Numerical solutions for displacements and stresses are compared with analytical solutions, while numerical solutions for stress intensity factor are compared with empirical solutions. The impact of the mesh density and near tip (NT) enrichment function are investigate...