Experimental determination of plastic zones

Czoboly, E.; Csizmazia, B.; Havas, I.

doi:10.1007/bf02538929

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…Distributions of elastoplastic strains near the tips of cracks or notches are analyzed by using both experimental and calculational methods. For their experimental determination, it is customary to use small strain gauges [5, 6], the methods of marks and small‐base nets [6, 7], photosensitive coatings [8], etc. In view of the fact that the fracture processes in notched bodies are actually governed not by the entire plastic zone but by the prefracture zone localised in the subsurface layers along the contour of the notch tips [1], these methods are characterised by significant shortcomings.…”

Section: Assessment Of the Local Strain Range δɛ*mentioning

confidence: 99%

Local Strain Measurement for Prediction of Fatigue Macrocrack Initiation in Notched Specimens

Ostash

Chepil

2003

Strain

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On the basis of direct measurement of the opening displacement of the notch contour the procedure of the evaluation of local elastoplastic strains range, De Ã , is developed. The experimental values of De Ã are compared with the calculational data using known equations by Neuber, Glinka, etc. It is shown that for De Ã < 2% the experimental and calculational values are in good agreement but only in the case when the gradient of strains near the notch tip is taken into account. The proposed experimental method is used for the prediction of period N i to fatigue macrocrack initiation in specimens of a complicated shape.

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Section: Assessment Of the Local Strain Range δɛ*mentioning

confidence: 99%

Local Strain Measurement for Prediction of Fatigue Macrocrack Initiation in Notched Specimens

Ostash

Chepil

2003

Strain

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“…The fracture mechanics, the testing and modelling of the crack propagation beginning with Griffith's equations [1][2][3][4][5] and research for the determination of the crack propagation. It was followed by the theories of Orowan [2,5,6], Paris [7,8], Erdogan [7,9], Tada [8], Irwin [10][11][12], Westergaard [13], Czoboly [14,15], Gillemot [15,16], and other important researches. For dynamic loading well known the Charpy impact and drop weight impact tests are.…”

Section: Introductionmentioning

confidence: 99%

Dynamic crack mechanism model place in the designing of the buildings

Nyikes¹,

Kovács

2021

MATEC Web Conf.

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The materials that we use always have some defects. Under static, cycling or dynamic load the materials as a function of the crack size and load environment can initiate a fracture. The crack mechanism depends on several factors, like material properties, crack type and the stress kind. The traditional fracture mechanics theories suggest several solutions to predict the crack-grow and the fracture. The fracture mechanism theories are well known in the case of the elastic-plastic behaviour materials and also for the brittle materials under different strain like a high cycle and low cycle fatigue load. These theories are supported by test results. Several researchers evaluated different test methods for determining the fracture toughness on the base of crack-grow behaviour by dynamic tests and determining dynamic fracture toughness. The paper brings the results of the brick blast resistance under the blast load. Damage level was detected as a function of the test setup parameters. The bricks were pre-cracked before the test. The results show that the fracture can be guided by the pre-cracking and decrease the blast affected damage.

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“…Consequently, unlike SIF, there is no adequate universal method for calculating the crack opening range and local strain, depending on the geometry of specimens, the crack length and the loading method, that is, there are no dependences similar to the K-calibration curves for the stress approach. Along with the analytical methods, experimental ones for determining the distribution of elastic-plastic strains in the crack tip vicinity are used [11][12][13][14][15]. For this purpose, smallsized strain gauges, a method of marks or coordinate grids, optical methods for direct observation, etc.…”

Section: Introductionmentioning

confidence: 99%

The diagnostics and ways heat treatment optimization of a railway wheels steel

Vira¹,

Kulyk²,

Chepil³

et al. 2019

Diagnostyka

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A high resolution sensor of linear displacements has been elaborated for diagnosing the size of the crack tip opening in standard test specimens. Based on the data measured during fatigue crack growth resistance tests of a wheel steel heat treated after various modes, calculations of the strain and energy parameters of local fracture were performed for the corresponding variants of treatment, and fatigue crack growth rate diagrams were constructed using different approaches of fatigue fracture mechanics. It was established that the diagrams obtained using the strain and energy approaches are more sensitive to material microstructure and its mechanical properties than the traditional diagrams obtained using the stress approach. Based on the parameters of the fatigue crack growth resistance estimated using the strain and energy approaches, the effective diagnostics and the best heat treatment mode for the wheel steel was developed. It comprises the stages of isothermal quenching and tempering at a temperature of 500 °С, providing the highest fatigue fracture toughness of the steel.

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Experimental determination of plastic zones

Cited by 4 publications

References 13 publications

Local Strain Measurement for Prediction of Fatigue Macrocrack Initiation in Notched Specimens

Local Strain Measurement for Prediction of Fatigue Macrocrack Initiation in Notched Specimens

Dynamic crack mechanism model place in the designing of the buildings

The diagnostics and ways heat treatment optimization of a railway wheels steel

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