Temat: fracture - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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.
Powiązania:: https://bibliotekanauki.pl/articles/387134.pdf
Data publikacji:: 2009
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: odporność na kruche pękanie
pękanie
fracture toughness
fracture
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.
Źródło:: Acta Mechanica et Automatica; 2009, 3, 3; 28-31
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

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.
Powiązania:: https://bibliotekanauki.pl/articles/298914.pdf
Data publikacji:: 2015
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:: casing strings
fracture pressure
pore pressure
fracture gradients
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.
Źródło:: AGH Drilling, Oil, Gas; 2015, 32, 2; 381-394
2299-4157
2300-7052
Pojawia się w:: AGH Drilling, Oil, Gas
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Application of cohesive model in fracture mechanics by WARP3D
Autorzy:: Gałkiewicz, J.
Powiązania:: https://bibliotekanauki.pl/articles/243336.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: finite element method
cohesive model
fracture mechanics
fracture process
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.
Źródło:: Journal of KONES; 2008, 15, 1; 69-77
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Temperature and hydrogen concentration influence on Zi -2.5Nb alloy mechanical and fracture toughness characteristics
Autorzy:: Daunys, M.
Dundulis, R.
Krasauskas, P.
Powiązania:: https://bibliotekanauki.pl/articles/386588.pdf
Data publikacji:: 2007
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: fracture
temperature
hydrogen
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.
Źródło:: Acta Mechanica et Automatica; 2007, 1, 1; 19-22
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Ductile fracture criterion for specimens with notches made of aluminium alloy EN-AW 2024
Autorzy:: Derpeński, Ł.
Seweryn, A.
Powiązania:: https://bibliotekanauki.pl/articles/280994.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: numerical analysis
fracture of specimen with notches
ductile fracture criterion
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.
Źródło:: Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1079-1093
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The key problems of local approach to cleavage fracture
Kluczowe zagadnienia w lokalnym ujęciu kruchego pękania
Autorzy:: Kotrechko, S.
Powiązania:: https://bibliotekanauki.pl/articles/279830.pdf
Data publikacji:: 2013
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: local approach to fracture
multi-scale model
local fracture stress
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.
Źródło:: Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 75-89
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: The Effect of Mn Content on the Structure and Properties of PM Mn Steels
Autorzy:: Tenerowicz, M.
Sułkowski, M.
Powiązania:: https://bibliotekanauki.pl/articles/354020.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: sinterhardening
furnace cooling fractography
ductile fracture
brittle fracture
PM Mn steels
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.
Źródło:: Archives of Metallurgy and Materials; 2017, 62, 4; 2153-2163
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Analysis of crack propagation in a "pull-out" test
Autorzy:: Gontarz, Jakub
Podgórski, Jerzy
Powiązania:: https://bibliotekanauki.pl/articles/178329.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: pull-out test
rock mechanics
fracture mechanics
numerical modeling of fracture
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.
Źródło:: Studia Geotechnica et Mechanica; 2019, 41, 3; 160-170
0137-6365
2083-831X
Pojawia się w:: Studia Geotechnica et Mechanica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Failure analysis of a femoral hip stem made of stainless steel after short time of exposure
Autorzy:: Mierzejewska, Ż. A.
Oksiuta, Z.
Powiązania:: https://bibliotekanauki.pl/articles/386661.pdf
Data publikacji:: 2014
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: hip replacement
endoprosthesis stem fracture
isolated fracture
total hip arthroplasty complications
fatigue fracture
proteza stawu biodrowego
endoproteza
pękanie zmęczeniowe
Opis:: This paper describes a case study summarising the failure analysis of a stainless steel femoral stem, which failed prematurely within 36 months of exploitation in human body. In order to determine the mechanism of failure, a broken stem component were analyzed by means of macroscopic and microscopic obserwations and hardness measurements. Metallurgical obserwations revealed that the tested material does fulfill ASTM requirements. Scanning electron microscopy images revealed the presence of stress-induced cracking. The results of the hardness revealed significant nonuniformity from the surface towards the inner part of the stem. It is assumed that any discontinuity or defect on the fracture surface of the stem acted as preferential site for a crack nucleation and propagation by fatigue until the cross section of stem was not able to sustain a load generated by a patient.
Źródło:: Acta Mechanica et Automatica; 2014, 8, 3; 146-150
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Epidemiological assessment of maxillofacial fractures in inhabitants of Lower Silesia, Poland, in 2002-2006 - Treatment of maxillofacial fracture
Autorzy:: Parulska, O.
Dobrzynski, M.
Bazan, J.
Calkosinski, I.
Powiązania:: https://bibliotekanauki.pl/articles/3318.pdf
Data publikacji:: 2015
Wydawca:: Instytut Medycyny Wsi
Tematy:: epidemiology
maxillofacial fracture
treatment
fracture
inhabitant
Lover Silesia
Polska
2002-2006 period
Opis:: Introduction and objective. Epidemiological assessment of maxillofacial fractures carried out by a given specialized centre may constitute valuable material for comparison with other regions of Poland and the European Union. This material could help standardize the present methods of treating craniofacial skeleton dislocations, and plan appropriate financial resources both for specialized treatment of such fractures and fractures that require multidisciplinary care. Moreover, the frequency of complicated maxillofacial fractures leading to residual disability and circumstances in which fracture occurred may be useful for the Social Security authorities. Materials and methods. This study is a continuation of research on maxillofacial traumatology carried by the Maxillofacial Department of the Medical University in Wrocław, Lower Silesia. Since 1956, a statistical review of maxillofacial fractures has been kept in 5 or 10-year periods. Statistical analysis of this kind is useful in indentifying the frequency of the phenomenon, taking suitable treatment precautions, verifying treatment methods, and analyzing costs and losses incurred as a result of absence at work. Sociological aspect of such studies includes indicating sources of socially adverse phenomena, i.e. violence or alcohol abuse. The studies were based on clinical documentation of 937 patients, where dependencies between chosen parameters were identified. As a basic statistical analysis of variable interdependence the χ2 test of independence was applied. Conclusions. Lately, there have been more maxillofacial fractures resulting from civilization changes. Simultaneously, there are new treatment methods and significant progress has been made regarding materials that are used in these treatments.
Źródło:: Journal of Pre-Clinical and Clinical Research; 2015, 09, 1
1898-2395
Pojawia się w:: Journal of Pre-Clinical and Clinical Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: The relationship between double-K parameters of concrete based on fracture extreme theory
Autorzy:: Nie, Yatong
Qing, Longbang
Powiązania:: https://bibliotekanauki.pl/articles/281708.pdf
Data publikacji:: 2020
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: initial fracture toughness
unstable fracture toughness
theoretical relationship
simplified extreme method
softening function
Opis:: The theoretical relationship between the initial fracture toughness and unstable fracture toughness in the double-K model was established based on fracture extreme theory. Using this relationship, the initial fracture toughness and unstable fracture toughness can be ob- tained from each other without experimental measurement. The values of unstable fracture toughness of three-point bending concrete beams were calculated with the input of initial fracture toughness. The calculation was simplified by using the weight function method. The calculated results were compared with those obtained by the double-K method. It is shown that the results obtained from these two methods show a good agreement. Unstable fracture toughness is affected by tensile strength and specimen size whereas unaffected by the ratio of initial crack length to depth. In addition, the softening function was found to have a negligible influence on the calculated result by a theoretical relationship.
Źródło:: Journal of Theoretical and Applied Mechanics; 2020, 58, 1; 59-71
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Study on mechanical characteristics of rock type I fracture and anchorage strengthening mechanism
Autorzy:: Zhang, Wei
Zhao, Tongbin
Guo, Weiyao
Xing, Minglu
Powiązania:: https://bibliotekanauki.pl/articles/2104761.pdf
Data publikacji:: 2022
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: anchor rock
fracture type of I
fracture toughness
three-point bending test
toughening
Opis:: Engineering rocks are easily affected by excavation unloading and are in uniaxial compres- sion or tension, forming a typical I-type tension crack. Anchor rods are often used for on-site support to ensure safety and reliability of the project. The study of propagation and pen- etration of type I tension cracks and quantitative evaluation of rock anchoring effects are of great significance for exploring mechanical properties of rock fracture and revealing the mechanism of rock failure. In this paper, combined with speckle light measurement, a rock fracture toughness test of different anchoring positions and pre-tightening forces is carried out, the deformation evolution law of the crack tip and the fracture mechanics characteris- tics of the anchored rock are obtained, and the anchoring strengthening mechanism of the rock is discussed based on the theory of the net stress intensity factor. The research shows that the rock fracture process is divided into four stages: elastic deformation, steady crack propagation, crack instability propagation and residual deformation. After anchoring, the time of crack instability growth can be prolonged by 172% and the final residual deformation can be increased by 148%. Compared with the unanchored rock, the fracture toughness of rock initiation and instability increased by 83% and 124% respectively, and increased with growth of the pre-tightening force, which shows that the bolt increases the critical value of rock initiation and instability to achieve the toughening effect. After the rock is anchored, the time required for the crack to propagate to the same length increases by 55%, and the lateral deformation area is reduced by 46%, indicating that the lateral closing force of the bolt inhibits crack propagation and delays the instability of the rock matrix.
Źródło:: Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 423--434
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: The Effect of Undercut Anchor Diameter on the Rock Failure Cone Area in Pullout Tests
Autorzy:: Jonak, Józef
Karpiński, Robert
Wójcik, Andrzej
Siegmund, Michał
Powiązania:: https://bibliotekanauki.pl/articles/2204399.pdf
Data publikacji:: 2022
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: rock mechanics
fracture mechanics
rock destruction
concrete breakout failure
numerical modelling of fracture
Opis:: The numerical analysis was conducted using the FEM ABAQUS software to establish the impact of various undercut anchor diameters on the rock breakout cone formation. The central focus of the investigations was on the rock breakout prism, which tends to be approximated to a cone or a quadrilateral pyramid, including its characteristic parameter, the angle of failure cone . Assuming that the embedment depth and the undercut anchor head angle were constant for the considered range of anchor head diameters, it remains unclear, however, precisely how the anchor head diameter affects the value of the failure cone angle, and thus the surface area of the full breakout prism. This conclusion stands in confirmation of our former considerations regarding the impact of the anchor head angle on the size of the breakout surface. Furthermore, it is supported by the results obtained from the mechanical model simulation of the anchor-rock system, where the anchor head angle and the effective embedment depth were determined as significant factors affecting the assumed rock breakout failure. The underlying aspect of the reported investigation was to evaluate the effectiveness of the non-conventional rock breakout technology performed with an undercut anchor, whose primary factors were both the pullout force and the assumed volume of the rock cone.
Źródło:: Advances in Science and Technology. Research Journal; 2022, 16, 5; 261-270
2299-8624
Pojawia się w:: Advances in Science and Technology. Research Journal
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Operative treatment of bone fracture with Kirschner wires – young cat case
Autorzy:: Ziąbka, M.
Derkowski, P.
Powiązania:: https://bibliotekanauki.pl/articles/284836.pdf
Data publikacji:: 2017
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:: bone fracture
Kirschner wires
implants
Źródło:: Engineering of Biomaterials; 2017, 20, no. 143 spec. iss.; 46
1429-7248
Pojawia się w:: Engineering of Biomaterials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Geomechanical aspects of hydraulic fracture propagation in the Lublin shale gas field in Poland
Autorzy:: Dhital, Ch.
Knez, D.
Śliwa, T.
Powiązania:: https://bibliotekanauki.pl/articles/299235.pdf
Data publikacji:: 2015
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:: shale gas
hydraulic fracture simulation
Opis:: The recent boom in shale gas exploration around the world has sparked a paradigm shift in energy security in many countries in the world. With the successful exploration of shale gas production in the United State’s, many operators are trying to replicate the success in other parts of the world specifically in European countries where the presence of organic rich shale deposits have signaled a promising investment for the recovery of shale gas. Perspective studies for the Polish shale gas field in Poland have been ongoing. One part of this project is the comparison of hydraulic fracture thickness between the U.S shale gas field and Polish for better and effective design and modeling of reservoirs for the optimal exploration and recovery of shale gas. Successful production of natural gas from Polish basins requires a hydraulic fracture stimulation to unlock the gas trapped in the shales coupled with a geologic analysis of the shale rocks.
Źródło:: AGH Drilling, Oil, Gas; 2015, 32, 4; 703-711
2299-4157
2300-7052
Pojawia się w:: AGH Drilling, Oil, Gas
Dostawca treści:: Biblioteka Nauki

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