Accuracy of Approximation of Stress and Displacement Fields in Cracked Body for Estimation of Failure Zone Extent / Přesnost Aproximace Polí Napětí A Posunů V Tělese S Trhlinou Pro Odhad Rozsahu Zóny Porušení

Sobek, Jakub; Veselý, Václav; Šestáková, Lucie

doi:10.2478/v10160-012-0031-5

Cited by 5 publications

(7 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2 Note that numerous authors' experience with the ODM application have been applied during the analysis (corresponding for instance to the number of nodes used for the ODM evaluation, or FE mesh parameters etc., see e.g. [3][4][5][6][7][8]). However, although a relatively high number of nodes has been used for investigations (k = 50) and their distance from the crack tip was large enough, it has not led to better convergence.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Williams Expansion Terms and their Importance for Accurate Stress Field Description in Specimens with a Crack

Malíková¹,

Veselý²

2013

TransVSBms

Self Cite

View full text Add to dashboard Cite

The paper deals with an analysis of the stress and displacement fields in various cracked specimens (loaded in mode I as well as in mode II). The main goal is to determine an accurate approximation of the near-crack-tip fields which can be subsequently used e.g. in the case of quasi-brittle materials for estimation of the extent of a nonlinear zone at the crack tip in general, the fracture process zone in particular. Values of coefficients of the so-called higher-order terms of the power expansion by which the fields can be expressed are determined via regression from results of numerical simulations. The analysis is conducted using 2D numerical models and ANSYS FE computational system is employed. Various aspects regarding the description of the stress/displacement fields by means of the Williams expansion are discussed; especially the convergence of the coefficients of the first several terms of the series expansion, their absolute values and importance for an accurate stress approximation. AbstraktČlánek se zabývá analýzou polí napětí a posuvů u několika těles s trhlinou (zatížených módem I i II). Hlavním cílem je přesně aproximovat zmiňovaná pole v blízkosti vrcholu trhliny, což může být následně využito např. pro odhad rozsahu obecně nelineární zóny u čela trhliny, konkrétně lomové procesní zóny v případě kvazi-křehkých materiálů. Hodnoty koeficientů tzv. členů vyšších řádů mocninného rozvoje, pomocí kterého mohou být ona pole vyjadřována, jsou určovány pomocí regrese na základě výsledků numerických simulací. Analýza je prováděna na 2D numerických modelech realizovaných ve výpočtovém systému ANSYS. Diskutovány jsou různé aspekty popisu polí napětí/posuvů pomocí Williamsova rozvoje; především konvergence koeficientů prvních něko-lika členů řady, jejich absolutní hodnoty a význam pro přesnou aproximaci napětí.

show abstract

Section: Resultsmentioning

confidence: 99%

“…More details about the ODM can be found for instance in [2] or in some of the authors' works devoted to parametric studies on ODM accuracy, convergence, or mesh sensitivity etc., see e.g. [3][4][5][6][7][8].…”

Section: Over-deterministic Methodsmentioning

confidence: 99%

Williams Expansion Terms and their Importance for Accurate Stress Field Description in Specimens with a Crack

Malíková¹,

Veselý²

2013

TransVSBms

Self Cite

View full text Add to dashboard Cite

show abstract

“…[18,19]. Application of multi-parameter elastic fracture mechanics [5,13,15] will provide determination of dimensionless shape functions for specimens with initial chevron notch for all configurations.…”

Section: Resultsmentioning

confidence: 99%

“…Only the symmetrical half of the specimen's body was used with the plane stress condition [15] -the reason was the simulation of non-uniform thickness of the notch layer along the height of the cross section. Figs.…”

Section: Numerical Proceduresmentioning

confidence: 99%

Determination of Stress Intensity Factor Value for Chevron-Notched Specimens – Pilot Study

Sobek¹,

Seitl²

2017

Transactions of the VŠB – Technical University of Ostrava, Civil Engineering Series.

Self Cite

View full text Add to dashboard Cite

The description of material behavior is one of important information for its application in civil engineering. One area is covering fracture mechanical properties. For evaluation of the fracture toughness values, the knowledge of calibration curve is important. The paper is aimed on the numerical modelling of the test specimens with a chevron notch serving as an initiator of the stress distribution at the crack tip. The three-point bending test configuration with a chevron notch is used for the simulation given by plane model with different layer width of cross section part and output is given by the value of the stress intensity factor K I for tension loading mode. KeywordsChevron notch, fracture test, stress intensity factor, three-point bending. INTRODUCTIONThree-point bending (3PB [1]) destructive testing of quasi-brittle materials is established procedure of testing various building structures (and its parts). Fracture tests are upgraded by adding the so-called stress concentratorsinitial notches, usually made in the horizontal direction at the bottom part of the normalized test specimen, which can be taken from the construction in the form of core drill. Originally, for the ductile materials, the initial notch in the form of chevron (V-shape) notch was designed (since 1964 [2,3,4]). It allows crack propagation to be directly in the central plane direction of the test specimen because the crack initiates from the sharp edge of the chevron notch (see Fig. 1 and 2). This type of initial notch can be used both for oval shape and rectangular/cube

show abstract

“…in. 21,26,45,46 Figure 5 depicts other variants of the models and indicates the location of the 'real' loading points, i.e. the bearing axles, for which (apart from the crack tip ring) the displacements were monitored (horizontal, d ax,hor , and vertical, d ax,vert ).…”

Section: N U M E R I C a L S T U D Ymentioning

confidence: 99%

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

Veselý

Frantík

Sobek

et al. 2014

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

This paper is aimed at the approximation of the stress and displacement fields both in the vicinity and also at a larger distance from the crack tip in test specimens utilised for the determination of the fracture characteristics of quasi‐brittle materials. A novel geometry is considered, which, with changes in the specimen's shape proportions, offers a wide variety of crack tip constraint levels and consequently also a broad range of extents/shapes of the nonlinear zone evolving around the crack tip. The combination of (four‐point) bending and wedge splitting tests of notched prismatic specimens is proposed and numerically investigated. Several variants of boundary conditions are modelled. The stress intensity factor K, the T‐stress and the coefficients of even higher‐order terms of the Williams series are determined and subsequently utilised for analytical approximations of the stress field. The agreement between the analytical and numerical solution depending on the distance from the crack tip and the number of terms of the series, and taking into account the analytical expression, is discussed. The presented approach is expected to be a suitable technique employed as part of a procedure being developed for the estimation of the fracture process zone extent in silicate composite materials. Such materials are characterised by their quasi‐brittle fracture response, which is caused by the softening of the material in the nonlinear zone. It is shown that changes in specimen proportions and/or the positions of supports slightly influence the crack tip constraint level resulting in possible differences in the width of the nonlinear zone.

show abstract

Accuracy of Approximation of Stress and Displacement Fields in Cracked Body for Estimation of Failure Zone Extent / Přesnost Aproximace Polí Napětí A Posunů V Tělese S Trhlinou Pro Odhad Rozsahu Zóny Porušení

Cited by 5 publications

References 7 publications

Williams Expansion Terms and their Importance for Accurate Stress Field Description in Specimens with a Crack

Williams Expansion Terms and their Importance for Accurate Stress Field Description in Specimens with a Crack

Determination of Stress Intensity Factor Value for Chevron-Notched Specimens – Pilot Study

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

Contact Info

Product

Resources

About