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Wyszukujesz frazę "fracture" wg kryterium: Temat


Tytuł:
The importance of the formation and fracture pressures for the selection of the depths for casing setting in Slovakia
Autorzy:
Pinka, J.
Kucirkova, L.
Tematy:
casing strings
fracture pressure
pore pressure
fracture gradients
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Data publikacji:
2015
Powiązania:
https://bibliotekanauki.pl/articles/298914.pdf  Link otwiera się w nowym oknie
Źródło:
AGH Drilling, Oil, Gas; 2015, 32, 2; 381-394
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Opis:
Different oil companies place shallow casing strings at different depths. Apparently there is no general method or procedure that gives the optimal location. This article is an attempt to define this optimum casing seat location. The potential benefits will improve safety and economy of the operation. The two major factors determine the depth of the casing shoe, that is, the fracture pressure and the pore pressure. A third factor is the lithology, because it is desirable to place the casing shoe in a competent shale section. The methods of predicting fracture gradients for deeper wells already exist. In this article, a method of predicting fracture gradients for shallow well has been derived. This method is combined with kick tolerance criteria to obtain a casing depth selection method. Also, the variation in fracture pressures at any depth has been investigated.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on ductile fracture criterion applied to shear fracture prediction of DP780 sheet
Autorzy:
Wu, Jiaxiong
Sun, Xuguang
Sun, Xiaoce
Chang, Fu
Yang, Shudi
Tan, Senqi
Tematy:
ductile fracture criterion
DP 780
fracture prediction
shear fracture
sheet forming
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Data publikacji:
2024
Powiązania:
https://bibliotekanauki.pl/articles/63161963.pdf  Link otwiera się w nowym oknie
Źródło:
Journal of Theoretical and Applied Mechanics; 2024, 62, 1; 143-156
1429-2955
2543-6309
Opis:
With the development of automotive lightweight technology, the improvement of the design of body sheet metal forming processes has gradually become a research focus. Advanced high-strength dual-phase steel is the main material for lightweight vehicle bodies, and exploring its accurate ductile fracture criteria plays an important role in predicting the forming fracture behavior of the sheet metal. The characterizations of the plastic behavior of the DP780 sheet before fracture were performed by the Swift hardening model. Three sets of tests from pure shear to tensile-shear stress states are designed to calibrate the ductile fracture parameters of Lou-Huh, Cockcroft-Latham, and Rice-Tracey criteria. The calibrated parameters are used to predict tensile shear test fractures and punching fractures at small bend fillets of molds. The results show the Lou-Huh criterion can accurately predict the shear fracture behavior of the DP780 sheet in the low-stress triaxiality (0.08-0.33).
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyznaczanie parametrów odporności na pękanie materiałów quasi-kruchych na próbkach cylindrycznych z karbami
Determination of the fracture toughness parameters of the quasi-brittle material using cylindrical specimens
Autorzy:
Kazberuk, A.
Tematy:
odporność na kruche pękanie
pękanie
fracture toughness
fracture
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Data publikacji:
2009
Powiązania:
https://bibliotekanauki.pl/articles/387134.pdf  Link otwiera się w nowym oknie
Źródło:
Acta Mechanica et Automatica; 2009, 3, 3; 28-31
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Opis:
Zaproponowano metodę wyznaczania krytycznego współczynnika intensywności naprężeń materiału na ściskanych próbkach o przekroju kołowym z centralnie umieszczonym otworem w postaci rombu. Proces zniszczenia próbki postępuje od wierzchołku karbu typu V. Znając wartość obciążenia niszczącego oraz standardowe stałe materiałowe oblicza się krytyczny współczynnik intensywności naprężeń wykorzystując odkształceniowe kryterium pękania oparte na modelu Dugdale’a. Zagadnienie koncentracji naprężeń w otoczeniu wierzchołków otworu rozwiązano metodą osobliwych równań całkowych.
The method of determination of critical SIF of brittle and quasi-brittle material is presented. For the splitting cylindrical specimen with central diamond-shaped hole the stress intensity factors were calculated for arbitral vertex angle. The values of critical SIF was obtained considering the deformation fracture criterion based on Dugdale model of failure with assumption that fracture process zone starts from notch tip.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of cohesive model in fracture mechanics by WARP3D
Autorzy:
Gałkiewicz, J.
Tematy:
finite element method
cohesive model
fracture mechanics
fracture process
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Data publikacji:
2008
Powiązania:
https://bibliotekanauki.pl/articles/243336.pdf  Link otwiera się w nowym oknie
Źródło:
Journal of KONES; 2008, 15, 1; 69-77
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Opis:
In the paper cohesive model implemented in WARP3D code and an example simulation of crack growth analysis ispresented. Cohesive model is an effective tool for a crack growth analysis and it was a main reason to invent it. For the "dassica" constitutive equation the crack growth simulation in the finite element method (FEM) is not possible without an additional crack growth criterion. In the commercial FEM codes cohesive model is not very popular unfortunately. Usually it can be applied as user implemented elements. However there is a code free of charge with high reliability acknowledged in the literature with cohesive elements in standard library. This program is WARP3D and it is dedicated to numerical simulations of three dimensional fracture mechanics problems. The Dugdale's model, void creation, the cellular model of material, the cohesion-decohesion curve, behaviour of cohesive element, comparison of curve shapes for brittle and ductile fracture, the profile of the cohesive element in WARP3D, specimen geometry, changes of crack shape under increasing load, opening stress distribution in the uncracked ligament are presented in the paper.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The key problems of local approach to cleavage fracture
Kluczowe zagadnienia w lokalnym ujęciu kruchego pękania
Autorzy:
Kotrechko, S.
Tematy:
local approach to fracture
multi-scale model
local fracture stress
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Data publikacji:
2013
Powiązania:
https://bibliotekanauki.pl/articles/279830.pdf  Link otwiera się w nowym oknie
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 75-89
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Opis:
Based on the suggested multi-scale model of Local Approach (LA) to fracture, four main problems of LA are considered, namely: (i) the effect of micro-stress fluctuations on the crack nuclei instability; (ii) intensity of micro-crack nucleation and its influence on fracture probability; (iii) theoretical and experimental assessment of the value of threshold stress; (iv) stochastic analysis of “multi-barrier” effect at micro-crack growth in polycrystalline metal.
W oparciu o zaproponowany wieloskalowy model lokalnego sformułowania procesu pękania (Local Approach – LA) wyróżniono cztery podstawowe problemy do rozważenia: (i) efekt fluktuacji makronaprężeń na niestabilność jądra pęknięcia, (ii) intensywność zawiązywania się mikropęknięcia i jego wpływ na prawdopodobieństwo powstania przełomu, (iii) teoretyczne i eksperymentalne oszacowanie wartości naprężenia krytycznego, (iv) stochastyczna analiza efektu „wieloprogowego” na wzrost mikropęknięcia w metalu polikrystalicznym.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enophthalmos as a prognostic factor in blow-out fracture of the orbit. Retrospective study of over 700 cases
Autorzy:
Koryczan, Piotr
Zapała, Jan
Gontarz, Michał
Wyszyńska-Pawelec, Grażyna
Tematy:
enophthalmos
posttraumatic enophthalmos
pure blowout orbital fracture
orbital fracture
diplopia
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Data publikacji:
2021-02-19
Powiązania:
https://bibliotekanauki.pl/articles/56894273.pdf  Link otwiera się w nowym oknie
Źródło:
Folia Medica Cracoviensia; 2020, 60, 3; 53-63
0015-5616
Pojawia się w:
Folia Medica Cracoviensia
Opis:
The aim of the study was to determine the influence of posttraumatic enophthalmos in orbital blow-out fracture on the treatment results. The relationship between time from injury to treatment, type of surgical reconstruction, bone graft site, type of diplopia and treatment results were evaluated. The relationship between the location of the fracture and the degree of enophthalmos was also analyzed. The study included 730 patients, 128 women and 602 men, aged 4 to 77 years, average 28 years, treated because of orbital blow-out fracture in our Department between 1975 and 2015. The study included only patients with an isolated orbital floor or medial wall fracture, so-called „pure blow-out” or „internal blowout”. Fractures of the lower rim, roof or lateral wall of the orbit, as well as the coexistence of other fractures of the facial part of the skull, were excluding citeria from the study. Complete recovery in surgically treated patients was achieved in 405 (58.8%) patients, improvement in 179 (26%) and no improvement in 105 (15.2%) patients. The degree of post-traumatic enophthalmos affects the result of the treatment. The location of the orbital fracture affects the enophthalmos, in our group of patients the largest incidence occurred in the fracture located in the orbital floor combined with medial wall. Patients who underwent surgical treatment up to 14 days after the injury achieved better results than those postponed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ductile fracture criterion for specimens with notches made of aluminium alloy EN-AW 2024
Autorzy:
Derpeński, Ł.
Seweryn, A.
Tematy:
numerical analysis
fracture of specimen with notches
ductile fracture criterion
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Data publikacji:
2016
Powiązania:
https://bibliotekanauki.pl/articles/280994.pdf  Link otwiera się w nowym oknie
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1079-1093
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Opis:
The paper presents the experimental verification of the most frequently used ductile fracture criteria based on authors own experimental results and numerical calculations. Attention is drawn to the large discrepancy of results of fracture prediction and experimental data for six considered criteria. Based on own results, a new ductile fracture criterion for notched specimens is proposed. In the criterion, it is assumed that fracture initiation occurs when the maximum normal stress reaches a critical value depending on the maximum value of plastic shear strain.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature and hydrogen concentration influence on Zi -2.5Nb alloy mechanical and fracture toughness characteristics
Autorzy:
Daunys, M.
Dundulis, R.
Krasauskas, P.
Tematy:
fracture
temperature
hydrogen
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Data publikacji:
2007
Powiązania:
https://bibliotekanauki.pl/articles/386588.pdf  Link otwiera się w nowym oknie
Źródło:
Acta Mechanica et Automatica; 2007, 1, 1; 19-22
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Opis:
This paper deals with an investigation of temperature and hydrogen concentration influence on Ignalina NPP RBMK-1500 unit 2 reactor fuel channel tube material - Zr-2.5Nb zirconium alloy (TMT-2) mechanical and fracture toughness characteristics. Two types of specimens were used in this study - tensile and compact semi-natural specimens. Testing temperatures were selected from 20 to 300°C that correspond various operating regimes of the reactor. Made-up hydrogen saturated specimens were tested at hydrogen concentration levels from 52 up to 140 ppm m order to examine hydrogen influence on mechanical and fracture toughness characteristics of the alloy. Dependence of fracture toughness to various mechanical characteristics of the alloy was analysed. Investigation has shown correlation of stress intensity factor Kc to modified plasticity criterion of the alloy.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Mn Content on the Structure and Properties of PM Mn Steels
Autorzy:
Tenerowicz, M.
Sułkowski, M.
Tematy:
sinterhardening
furnace cooling fractography
ductile fracture
brittle fracture
PM Mn steels
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Data publikacji:
2017
Powiązania:
https://bibliotekanauki.pl/articles/354020.pdf  Link otwiera się w nowym oknie
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 4; 2153-2163
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Opis:
The aim of the study was to examine how a reduction of Mn content in PM steels will affect their plastic and strength properties. The results of mechanical, metallographic and fractography tests of sintered (PM) steels containing 1% and 2% Mn are reported and compared with those for 3% Mn PM steel. Höganäs iron powder grade NC 100.24, low-carbon ferromanganese Elkem and graphite powder grade C-UF were used as the starting powders. Powder mixes Fe-(1-2)%Mn-0.8%C were prepared in a Turbula mixer for 30 minutes. Following mixing, “dog bone” compacts were single pressed at 660 MPa, according to PN-EN ISO 2740 standard. Sintering of compacts was carried out in a laboratory tube furnace at 1120°C and 1250°C for 60 minutes in a mixture of 95%N2 – 5%H2 in a semi-closed container. Three types of heat treatment were then used: sinterhardening (cooling rate – 66°C/min), slow furnace cooling (cooling rate 3.5°C/min) and tempering at 200°C. The studies have shown a beneficial effect of the reduction of manganese on plastic properties (up to 7.96%), while maintaining fracture strengths (UTSs) comparable to those of steel with higher contents of manganese. Currently detailed studies of steel containing 1%Mn are conducted.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of crack propagation in a "pull-out" test
Autorzy:
Gontarz, Jakub
Podgórski, Jerzy
Tematy:
pull-out test
rock mechanics
fracture mechanics
numerical modeling of fracture
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Data publikacji:
2019
Powiązania:
https://bibliotekanauki.pl/articles/178329.pdf  Link otwiera się w nowym oknie
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 3; 160-170
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Opis:
The article describes a computer analysis of the pull-out test used to calculate the force needed to pull out a rock fragment and determine the shape of this broken fragment. The analyzed material is sandstone and porphyry. The analysis included the first approach to using own subroutine in the Simulia Abaqus system, that is, which task is undertaken to accurately determine the crack path of the Finite Element Method model. The work also contains a description of laboratory tests and analytical considerations.
Dostawca treści:
Biblioteka Nauki
Artykuł

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