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Numerical simulations of ductile fracture in steel angle tension members connected with bolts

Bernatowska Edyta

Civil and Environmental Engineering Reports

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2020

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Vol. 30, no. 2

32--54

EN

Numerical simulations of ductile fracture in steel angle tension members connected with bolts

2

Wpływ stopnia trójosiowości stanu naprężeń na wartość odkształcenia nukleacji mikropustek w stali S235JR

Kossakowski P., Wciślik W.

Przegląd Mechaniczny

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2013

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nr 3

15--21

PL

W niniejszym artykule podjęto próbę numerycznego wyznaczenia podstawowego parametru modelu GTN, jakim jest odkształcenie plastyczne konieczne do zainicjowania pustki. Wykorzystując model MES, wyznaczono rozkład naprężeń i odkształceń wokół wydzielenia Fe3C w stali S235JR w warunkach stopnia trójosiowości stanu naprężeń równego 0,516 i 0,739. Uzyskane rezultaty porównano z wynikami zamieszczonymi w pracy w której analizowano rozkłady odkształceń wokół wydzielenia w warunkach wysokiego stopnia trójosiowości stanu naprężeń wynoszącego 1,345.

EN

In the present paper an attempt was made to determine the basie parameter of GTN model, which is the plastic strain needed to initiate a void. Using the FEM model, the distribution of stesses and strains around the Fe3C separation in S235JR steel in conditions of stress state triaxiality equal to 0,516 and 0,739 was determined. Obtained results were compared with those given in the work, in which the distribution of deformation around the separation in high stress state triaxiality amounting to 1,345 was analyzed.

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Influence of initial porosity on strength properties of S235JR steel at low stress triaxiality

Kossakowski P. G.

Archives of Civil Engineering

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2012

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Vol. 58, nr 3

293-308

EN

The paper discusses the influence of the initial parameters on the strength parameters of S235JR steel at low stress triaxiality. The analysis was performed using the Gurson-Tvergaard-Needleman (GTN) material model, which takes into consideration the material structure. The initial material porosity was defined as the void volume fraction f0. The fully dense material without pores was assumed and the typical and maximum values of porosity were considered for S235JR steel in order to analyse the porosity effect. The strength analysis of S235JR steel was performed basing on the force-elongation curves obtained experimentally and during numerical simulations. Taking into consideration the results obtained, the average values of the initial void volume fraction fo = 0.001 for S235JR steel is recommended to use in a common engineering calculations for elements operating at low stress triaxiality. In order to obtain more conservative results, the maximum values of fo = 0.0024 may be used.

4

Effect of initial porosity on material response under multi-axial stress state for S235JR steel

Kossakowski P. G.

Archives of Civil Engineering

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2012

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Vol. 58, nr 4

445-462

EN

The effect of the initial porosity on the material response under multi-axial stress state for S235JR steel using the Gurson-Tvergaard-Needleman (GTN) material model was examined. Three levels of initial porosity, defined by the void volume fraction f0, were considered: zero porosity for fully dense material without pores, average and maximum porosity according to the metallurgical requirements for S235JR steel. The effect of the initial porosity on the material response was noticed for tensile elements under multi-axial stress state defined by high stress triaxiality sigma m/sigma e = 1.345. This effect was especially noticeable at the range of the material failure. In terms of the load-bearing capacity of the elements, the conservative results were obtained when maximum value of f0 = 0.0024 was used for S235JR steel under multi-axial stress state, and this value is recommended to use in the calculations in order to preserve the highest safety level of the structure. In usual engineering calculations, the average porosity defined by f0 = 0.001 may be applied for S235JR.