Use of instrumented charpy testing on the fracture toughness characterization of metallic materials

Pereira, Luiz Carlos; Blas, Juan Garcia de; Griza, Sandro; Darwish, Fathi Aref

doi:10.4322/2176-1523.20212469

Cited by 5 publications

(4 citation statements)

References 40 publications

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“…21 also shows that at displacement equal to 1.4 mm , the model shows a drop of the load, this may be attributed to the accumulation of damage, this drop of data was also shown in Shterenlikht work [4]. It was also observed that many conventional finite element simulations of impact Charpy tests reported in the literature, have not properly reproduced the impact Charpy loaddisplacement curve, and most models have just reproduced the propagation region but with high oscillations in the hardening region [32][33][34][35][36][37], therefore CAFE model is more suitable to simulate impact Charpy curves.…”

Section: Modified Charpy Cafe Modellingmentioning

confidence: 84%

Modelling the Charpy Impact Ductile-Brittle Transition of a Ship Plate Steel with CAFE Modelling

Cuamatzi-Meléndez,

Juarez-López

2024

KEM

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In the present work, a cellular automata finite element model (CAFE) was developed to model the ductile-brittle transition of a Grade A ship plate steel. Therefore, ductile and brittle cellular automata (CA) arrays of cells were created in the model to integrate material data at microstructural level, along with the ductile and brittle fracture processes. Microstructural data was analysed with Weibull distributions and incorporated in CAFE model using random number generators, along with ductile and brittle fracture parameters. Ductile fracture was modelled with Rousselier damage model; hence damage model parameters were calibrated with experimental data. Brittle fracture was modelled with Beremin model, and four different cleavage particles, found in a Grade A ship plate steel, were incorporated in CAFE model in order to model a competition of particles nucleating microcracks of critical size in the damage regions of Impact Charpy tests and four-point double-notch bend tests performed at low temperature. The mechanical properties the plate steel was measured in the transition region and incorporated in CAFE model, along with ductile-brittle transition rules. The present CAFE model was able to simulate distributions of microcracks in the notch region of four-point double-notch bend models (in the transition region), which correlated with experimental data. CAFE model was also able to simulate microvoids in the notch region of Charpy specimens along with the load-displacement Charpy curve for room test temperature, with very good agreement with experimental data. Once CAFE model was validated at micro and structural level, it was applied to model the typical scatter of impact Charpy energy values in the transition region of Grade A ship plate steel with good agreement with the measured ductile-brittle transition curved of the plate steel. Keywords: cellular automata, finite element modelling, ductile-brittle transition, damage modelling.

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Section: Modified Charpy Cafe Modellingmentioning

confidence: 84%

Modelling the Charpy Impact Ductile-Brittle Transition of a Ship Plate Steel with CAFE Modelling

Cuamatzi-Meléndez,

Juarez-López

2024

KEM

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“…In our opinion, it has been shown there that a typical set of post-fire tests pertaining to the determination of mechanical properties of structural steel after a fire incident should be mandatorily broadened by adding impact tests. If possible, these tests should be instrumented [9][10][11][12][13], with a hammer of sufficiently high potential energy, using appropriate data transmission and processing following the recommendations of the codes [14][15][16][17]. The applicability of these tests to forecasting structural steel resistance to brittle cracking has been proven many times (for example in [18]), though most of such tests did not refer to material cooled down after undergoing a fire incident.…”

Section: Introductionmentioning

confidence: 99%

Impact Fracture Surfaces as the Indicators of Structural Steel Post-Fire Susceptibility to Brittle Cracking

et al. 2023

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The results of experimental research on forecasting post-fire resistance to brittle failure of selected steel grades used in construction are presented and discussed in this paper. The conclusions are based on detailed analysis of fracture surfaces obtained in instrumented Charpy tests. It has been shown that the relationships formulated based on these tests agree well with conclusions drawn based on precise analysis of appropriate F–s curves. Furthermore, other relationships between lateral expansion LE and energy Wt required to break the sample constitute an additional verification in both qualitative and quantitative terms. These relationships are accompanied here by values of the SFA(n) parameter, which are different, depending on the character of the fracture. Steel grades differing in microstructure have been selected for the detailed analysis, including: S355J2+N—representative for materials of ferritic-pearlitic structure, and also stainless steels such as X20Cr13—of martensitic structure, X6CrNiTi18-10—of austenitic structure and X2CrNiMoN22-5-3 duplex steel—of austenitic-ferritic structure.

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“…In this research, instrumented impact Charpy tests were performed to analyze the ductile-brittle transition of Grade A ship plate steels. The use of these tests allows to measure the absorbed energy for each of the stages of the fracture process and the calculation of the fracture toughness parameters from the initiation energy quantity [14,34].…”

mentioning

confidence: 99%

Cleavage Micromechanisms Study in a Ship Plate Steel through Four-Point Double-Notch Bend and Charpy Tests

Melendez

Martínez²,

Bravo

et al. 2023

KEM

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In this work instrumented impact Charpy tests were performed to analyze the ductile-brittle transition of Grade A ship plate steels, which are composed of ferrite matrix with pearlite bands in the rolling direction (RD) and pearlite lands in the transverse direction (TD). Observations on fracture surfaces of Charpy specimens showed regions of cleavage from room to down temperatures, therefore blunt four-point double–notch bend specimens (4PBT), were also tested at 25°C, 0°C, –60°C and –196°C in RD and TD, to study cleavage nucleation and propagation mechanisms. In the RD the following four different cleavage microfeatures nucleated microcracks in the notch region of 4PBT in all test temperatures: lamellar-pearlite microstructure, pearlite-boundary, ferrite-grains boundary and grains ferrite-inclusions. However, in the TD at –60°C, close to the lower shelf, only lamellar-pearlite and pearlite-boundary microfeatures were found nucleating microcracks. Nevertheless, the higher density of microcracks was found in the RD. The biggest microcracks were developed in TD in pearlite lands of critical size, in all test temperature, which are the link for the development of microcracks of critical size, which can propagate and fracture steel plates. In RD most microcracks nucleated in a critical region of about 1mm from notch root for all test temperatures, however for the TD the critical region decreases with test temperature, from about 450 µm (+25°C), 370 µm (0°C) and 225µm (–60°C). The analysis also showed the effect of microstructure orientation on the number and size of microcracks, and microcracks arrest.

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Use of instrumented charpy testing on the fracture toughness characterization of metallic materials

Cited by 5 publications

References 40 publications

Modelling the Charpy Impact Ductile-Brittle Transition of a Ship Plate Steel with CAFE Modelling

Modelling the Charpy Impact Ductile-Brittle Transition of a Ship Plate Steel with CAFE Modelling

Impact Fracture Surfaces as the Indicators of Structural Steel Post-Fire Susceptibility to Brittle Cracking

Cleavage Micromechanisms Study in a Ship Plate Steel through Four-Point Double-Notch Bend and Charpy Tests

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