Determination of fracture toughness from the small punch test using circular notched specimens

2019 ◽

Vol 795 ◽

pp. 165-171

Author(s):

Wu Lin Wang ◽

Du Wei Wang ◽

Kai Shu Guan

Keyword(s):

Fracture Toughness ◽

Empirical Correlation ◽

Fracture Toughness Test ◽

J Integral ◽

Small Punch Test ◽

Small Punch ◽

Punch Test ◽

Determination Procedure ◽

Material Fracture

Fracture toughness empirical correlation between SPT(Small Punch Test) with non-crack sample and standard fracture toughness test has been established in recent years. In order to compensate the imperfection of empirical correlation, such as absence theoretical basis, poor repeatability and universality, in this paper, an O-type pre-cracked sample was adopted to evaluate fracture toughness. The mechanical model of the sample is in compliance with plane strain condition in the direction of crack propagation. In this paper a determination procedure was studied and established, and the J-integral of steel Q345R was calculated using the procedure.

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Rate effects on the estimation of fracture toughness by small punch tests in hydrogen embrittlement

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324719848243 ◽

2019 ◽

Vol 54 (7-8) ◽

pp. 390-400 ◽

Cited By ~ 1

Author(s):

Borja Arroyo ◽

Jose Alberto Álvarez ◽

Federico Gutiérrez-Solana ◽

Roberto Lacalle ◽

Pablo González

Keyword(s):

Fracture Toughness ◽

Hydrogen Embrittlement ◽

Slow Rate ◽

Environment Interaction ◽

Small Punch Test ◽

Small Punch ◽

Notched Specimens ◽

Punch Test ◽

Material Environment ◽

Rate Effects

In this article, different techniques to test notched small punch test samples in fracture conditions in aggressive environments are studied, based on the comparison of the micromechanisms at different rates. Pre-embrittled samples subsequently tested in air at rates conventionally employed (0.01 and 0.002 mm/s) are compared to embrittled ones tested in environment at the same rates (0.01 and 0.002 mm/s) and at a very slow rate (5E–5 mm/s). A set of samples tested in environment under a set of constant loads that produce very slow rates completes the experimental results. As a conclusion, it is recommended to test small punch test notched specimens in environment at very slow rates, of around E–6 mm/s, when characterizing in hydrogen embrittlement scenarios, in order to allow the material–environment interaction to govern the process.

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Determination of Strength and Fracture Toughness of Small Ceramic Discs Using the Small Punch Test and the Ball-on-three-balls Test

Procedia Materials Science ◽

10.1016/j.mspro.2014.06.156 ◽

2014 ◽

Vol 3 ◽

pp. 961-966 ◽

Cited By ~ 17

Author(s):

Stefan Rasche ◽

Stefan Strobl ◽

Meinhard Kuna ◽

Raul Bermejo ◽

Tanja Lube

Keyword(s):

Fracture Toughness ◽

Small Punch Test ◽

Small Punch ◽

Punch Test

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Use of Small Punch Notched Specimens in the Determination of Fracture Toughness

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2008-61537 ◽

2008 ◽

Cited By ~ 3

Author(s):

Roberto Lacalle ◽

Jose´ Alberto A´lvarez ◽

Federico Gutie´rrez-Solana

Keyword(s):

Fracture Toughness ◽

Small Punch ◽

Ship Building ◽

Damage Models ◽

Notched Specimens ◽

Punch Test ◽

Reduced Dimension ◽

Fracture Tests ◽

Lateral Notch

In recent years an increasing interest has been shown in materials characterisation techniques based on the use of reduced dimension samples. One of these techniques, first developed in the early 80’s, is Small Punch testing, in which a punch acts over a plane small specimen deforming it until fracture. So far, this test has been used as a tool for the estimation of mechanical properties, for characterising ductilebrittle transition or for knowing the evolution of these properties with ageing phenomena as neutron irradiation. The Small Punch Test has even been used in the determination of fracture toughness by means of indirect correlations or complex methodologies based on damage models and Finite Element simulations. In this paper, a direct methodology for the determination of fracture toughness from Small Punch tests is proposed. The approach is based on the use of simply modified Small Punch specimens in which a lateral notch was machined. Attending to energy considerations, the J-Δa curve for a ship-building Grade A steel, as well as for a structural steel, E690, has been obtained using this type of samples and the results have been compared with the calculated results from conventional fracture tests.

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