Effect of bimodularity and thermomechanical stresses from composite curing on mixed-mode fracture behavior of functionally graded skin-stiffener runout

The aim of this study was to examine the effect of size on the mixed-mode fracture toughness of quasi-brittle nanocomposites with the help of modified maximum tangential stress criterion. The literature reveals that the effect of size on mixed-mode fracture behavior of brittle nanocomposites has not been well investigated previously using modified maximum tangential stress criterion. The studied nanocomposites were made of epoxy resin reinforced with 7 wt%, 20–30 nm nanosilica. The accuracy of the method was assessed by taking into account the high-order terms of Williams series expansion along with finite element over-deterministic method. To investigate the effect of size on fracture toughness, a number of three-point semi-circular bending tests with different radii and four angles of edge–crack orientation were conducted and subjected to mixed-mode loading. The size of fracture process zone and apparent fracture toughness ( Kc) were also evaluated as a function of sample size. Experimental results showed that the proposed approach can accurately predict the fracture behavior of studied nanocomposites.

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The mixed-mode fracture mechanics analysis of an embedded arbitrary oriented crack in a two-dimensional functionally graded material plate

Archive of Applied Mechanics ◽

10.1007/s00419-014-0821-6 ◽

2014 ◽

Vol 84 (5) ◽

pp. 625-637 ◽

Cited By ~ 6

Author(s):

Mohammad R. Torshizian ◽

Mohammad H. Kargarnovin

Keyword(s):

Fracture Mechanics ◽

Functionally Graded Material ◽

Mixed Mode ◽

Functionally Graded ◽

Mixed Mode Fracture ◽

Two Dimensional ◽

Mode Fracture ◽

Mechanics Analysis ◽

Graded Material

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Numerical studies on mixed-mode crack propagation behavior for functionally graded material based on peridynamic theory

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684118500276 ◽

2018 ◽

Vol 07 (04) ◽

pp. 1850027 ◽

Cited By ~ 1

Author(s):

Fei Wang ◽

Yu’e Ma ◽

Yanning Guo ◽

Wei Huang

Keyword(s):

Crack Propagation ◽

Mixed Mode ◽

Fracture Behavior ◽

Damage Model ◽

Fortran Program ◽

Functionally Graded ◽

Mixed Mode Fracture ◽

Stress Load ◽

Gradient Direction ◽

Mixed Mode Crack

Peridynamics (PD) is a new nonlocal theory that unifies the mechanics of discrete particles, continuum, and continuum with discontinuities, and it has inherent advantages in calculating the mixed-mode crack propagating. Functionally graded materials (FGMs) are the advanced composite materials, fracture behavior of which is complicated to be simulated by the traditional continuum mechanics. Hence, a PD model for FGMs is given to investigate the mixed-mode fracture behavior under quasi-static loading. Basic PD equations, damage model, and PD [Formula: see text]-integral for FGMs are discussed. A FORTRAN program of PD algorithm is coded to calculate the [Formula: see text]-integral and crack propagation of FGMs. The [Formula: see text]-integral and the crack paths of the PD model are verified by comparing with the published numerical and experimental results. Effects of the material gradient, the material gradient direction, and the stress load magnitude on the fracture behavior are investigated. It is shown that the PD [Formula: see text]-integral and the crack path are strongly affected by the material gradient and the gradient direction under the same stress load. When the gradient of FGMs is linear, the material gradient direction decides whether the mixed-mode crack kinks or not and the magnitude of stress determines the kinking angle.

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