Multi-parameter crack tip stress state description for estimation of fracture process zone extent in silicate composite WST specimens

Abstract

For wedge splitting test specimens, the stress and displacement fields both in the vicinity and also in larger distance from the crack tip are investigated by means of numerical methods. Several variants of boundary conditions were modeled. The stress intensity factor K, T-stress and even higher-order terms of William series were determined and subsequently utilized for analytical approximation of the stress field. A good fit between the analytical and numerical solution in dependence on the distance from the crack tip was shown, compared and discussed. Presented approach is considered as suitable for estimation of the fracture process zone extent in silicate composite materials.

Multi‐parameter crack tip stress state description for evaluation of nonlinear zone width in silicate composite specimens in component splitting/bending test geometry

“…The test can be performed on specimens of various shapes; however, also the test setup, that is, the boundary conditions, can also significantly differ. In typical fracture analyses, details of boundary conditions related to both the load application and the specimen supports are usually neglected, which can lead to substantial errors . In particular, the compressive component of the loading force ( P v in Figs.…”

“…A procedure for the determination of the true values of fracture parameters of structural materials taking into account the aforementioned effects is currently under development by the authors. The outputs of individual parts of the procedure are being tested, verified and validated at present, both from the perspective of FPZ extent estimation (analytically and using simulations, and experimentally) and also of crack tip stress state description . This paper is particularly focused on the analytical/numerical investigation of differences between crack tip stress states caused by changes in test geometry (the specimen's shape and boundary conditions) resulting in differences in the extent (particularly width) of the FPZ.…”

“…The outputs of individual parts of the procedure are being tested, verified and validated at present, both from the perspective of FPZ extent estimation (analytically and using simulations, 16,17 and experimentally [18][19][20] ) and also of crack tip stress state description. [21][22][23][24][25][26][27] This paper is particularly focused on the analytical/numerical investigation of differences between crack tip stress states caused by changes in test geometry (the specimen's shape and boundary conditions) resulting in differences in the extent (particularly width) of the FPZ. Another novelty of this paper is the proposal of a test geometry derived from a combination of what is referred to as wedge splitting test (WST) geometry and the typical four-point bending test carried out on notched beams.…”

Significance of Higher-order Terms of the Williams Expansion for Plastic Zone Extent Estimation Demonstrated on a Mixed-mode Geometry

“…Šestáková (2014a,b), Šestáková et al (2013), Veselý et al (2014) and Veselý et al (2013) for more details. Further investigations in this area are introduced in this paper.…”

Multi-parameter fracture criteria for the estimation of crack propagation direction applied to a mixed-mode geometry

“…The authors' works, see e.g. [13][14][15][16][17][18], as well as others, show that using more terms of the series expansion enables the crack-tip stress field to be expressed more effectively than if only the first term, equivalent to the stress intensity factor, is considered.…”