Temat: strength limit - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Method for calculation of the carrying capacity of the bottomhole zone of a gas-bearing formation
Autorzy:: Rizo, Zakhar
Vasyliev, Leonid
Vasyliev, Dmytro
Avramenko, Stanislav
Tematy:: rock
strength limit
destruction
crack
bottomhole zone; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Powiązania:: https://bibliotekanauki.pl/articles/58972504.pdf Link otwiera się w nowym oknie
Opis:: This paper presents a method for calculating vertical and horizontal stresses in gas-bearing coal seams based on a set of equations developed by the authors. The method describes the experimental curve of rock pressure as a convex quadratic function, with the initial value of the function equal to the normal stress at the top of the bottom hole crack. The method also considers the variation of gas pressure as the crack moves towards the interior of the formation. In addition, the method employs the relationship between active tangential stresses at points on the edges of the bottomhole crack, derived from Coulomb’s strength criteria for brittle materials. The accuracy of the method was confirmed by experimental data on the maximum shear strength of marble and brown coal at various levels of confining pressure and pore pressure. The paper also presents analytical expressions for the strength limit of the bottomhole zone of gas-bearing coal seams as a function of gas pressure gradient.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Influence of effectiveness speed in mechanical properties of AW6060 T66 (PA38) alloy
Autorzy:: Panasiuk, K.
Tematy:: alloy aluminum
static load
dynamic load
yield strength
strength limit; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/247214.pdf Link otwiera się w nowym oknie
Opis:: The article examines the effect of the change in the speed of deformation on the mechanical properties of AW 6060 alloy specimens, characterized by high mechanical strength, which is a material used in the shipbuilding industry. The theoretical basis for the influence of load speed on the mechanical properties of materials is presented. Static and dynamic tensile test was conducted on a universal testing machine. Dynamic stretching was performed on samples at 10–1 s–1 – 102 s–1. Done charts and tables showing results. Calculated in accordance with DIN EN ISO 6892-1 2010P total elongation and contraction of the sample. Comparison of the results of the study with the current knowledge of the subject. Material studies have shown that increasing the deformation rate results in an increase in the yield point and tensile strength. On the basis of calculations of the narrowing and elongation of the total sample, the material can be strengthened. The rate of deformation of the materials is favourable for their strengthening by increasing the limit of tensile strength. Given that most of the design is subject to dynamic loads and the aluminum alloy AW 6060 finds extensive use in shipbuilding and beyond, these are satisfactory results.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A Study of The Properties of Forming Mixtures Containing Polystyrene Wastes
Autorzy:: Dan, Olena
Trofimova, Larysa
Tematy:: waste
solution
polystyrene
turpentine
strength limit
sprinkling
residual strength
odpady
rozwiązanie
styropian
terpentyna
granica wytrzymałości
posypywanie
wytrzymałość resztkowa; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/2056024.pdf Link otwiera się w nowym oknie
Opis:: Expanded polystyrene is widely used as a material for packaging, in modern construction as a heat and sound insulation layer, in thermal insulation systems for buildings, as well as tanks and pipelines. It is additionally used in foundry engineering for the production of models which are gasified during the production of castings from ferrous and non-ferrous alloys under the contact with liquid metal. The use of expanded polystyrene products is associated with waste generation, both in production and in consumption. About 40–50 kg/person of polystyrene waste is generated per year. The peculiarity of polymeric wastes is their resistance to aggressive environments. They do not rot and the destruction processes in natural conditions proceed rather slowly, with the formation of harmful substances that poison the environment. Therefore, the problem of the processing of waste from polymeric materials is of great importance, not only from the standpoint of environmental protection, but also due to the fact that in conditions of a shortage of polymer raw materials, this waste becomes a powerful raw material resource. This article describes the prospects for recycling expanded polystyrene wastes in foundry engineering. In this work, the properties of molding and core sands containing a combined binder, consisting of a solution of expanded polystyrene wastes in turpentine and clay were investigated, and their main characteristics (weight during stretching and crumbling) were determined. Molding and core mixtures, which contain only a binder in the form of a solution of expanded polystyrene in turpentine, have a crude strength of not more than 0.01 MPa. The introduction of a mixture of clay in the amount of 2–3% allows a crude strength of the mixture of up to 0.05 MPa to be obtained. After drying, the investigated mixtures containing a solution of expanded polystyrene wastes and clay have a tensile strength of up to 2.1 MPa. Mixtures into which a solution of polystyrene wastes and clay was introduced have an insignificant gas capacity and satisfactory gas permeability.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Impact of the type of quench aging after hyperquenching on the mechanical strength properties of AW-7020 alloy
Autorzy:: Hajdukiewicz, G.
Tematy:: AW-7020 alloy
age hardening
natural aging
artificial aging
hyperquenching strength limit
rupture elongation
fracture area reduction
intermediate state
age process hardening; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/247335.pdf Link otwiera się w nowym oknie
Opis:: The article attempts to determine the influence of selected types of the heat treatment on the strength properties of the AW-7020 alloy used in the shipbuilding industry. The text presents information on the applied types of heat treatment. There are presented the results of the static tensile test of the material after its earlier hyperquenching and aging (natural and artificial) as well as comparison to the test results of the alloy without heat treatment. To illustrate the nature of the supersaturation and aging process, a test was carried out for a series of samples in a transitional state. During the tests for all the samples were determined: elongation at rupture and reduction of area at fracture, strength limit Rm and proof stress Re0.2. The results of the tests showed that the choice of the type of aging after saturation has significant importance for the strength properties of the AW-7020 alloy. It has been shown that it is possible to significantly accelerate the achievement of higher strength properties of the tested alloy, replacing the natural aging of the material with artificial aging.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Bearing capacity of the working platform with kinematic method
Autorzy:: Białek, K.
Bałachowski, L.
Tematy:: soft soil
undrained shear strength
limit state
failure mechanism; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/178343.pdf Link otwiera się w nowym oknie
Opis:: Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Influence of wood-derived biochar on the compactibility and strength of silt loam soil
Autorzy:: Ahmed, Ahmed
Gariepy, Yvan
Raghavan, Vijaya
Tematy:: biochar
particle size
bulk density
proctor
compaction
plastic and liquid limit
penetration resistance
soil
shear strength; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/973197.pdf Link otwiera się w nowym oknie
Opis:: Biochar is proven to enhance soil fertility and increase crop productivity. Given that the influence of biochar on soil compaction remains unclear, selected physico-mechanical properties of soil amended with wood-derived biochar were assessed. For unamended silt loam, the bulk density, maximum bulk density, optimum moisture content, plastic limit, liquid limit, and plasticity index were 1.05 Mg m-3, 1.69 Mg m-3, 16.55, 17.1, 29.3, and 12.2%, respectively. The penetration resistance and shear strength of the unamended silt loam compacted in the standard compaction Proctor mold and at its optimum moisture content were 1800 kPa and 850 kPa, respectively. Results from amending the silt loam with 10% particle size ranges (0.5-212 μm) led to relative decreases of 18.1, 17.75, 66.66, and 97.4% in bulk density, maximum bulk density, penetration resistance, and shear strength, respectively; a 26.8% relative increase in optimum moisture content; along with absolute increases in plastic limit, liquid limit, and plasticity index of 5.3, 13.7, and 8.4%, respectively. While the biochar-amended silt loam soil was more susceptible to compaction, however, soil mechanical impedance enhanced.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Assessment of Failure Strength of Real Alumina Foams with Use of the Periodic Structure Model
Autorzy:: Nowak, M.
Nowak, Z.
Pęcherski, R. B.
Potoczek, M.
Śliwa, R. E.
Tematy:: periodic cell structure
alumina open-cell foam
Young modulus
strength of alumina foams
Burzyński limit criterion; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352701.pdf Link otwiera się w nowym oknie
Opis:: The subject of the study are alumina foams produced by gelcasting method. The results of micro-computed tomography of the foam samples are used to create the numerical model reconstructing the real structure of the foam skeleton as well as the simplified periodic open-cell structure models. The aim of the paper is to present a new idea of the energy-based assessment of failure strength under uniaxial compression of real alumina foams of various porosity with use of the periodic structure model of the same porosity. Considering two kinds of cellular structures: the periodic one, for instance of fcc type, and the random structure of real alumina foam it is possible to justify the hypothesis, computationally and experimentally, that the same elastic energy density cumulated in the both structures of the same porosity allows to determine the close values of fracture strength under compression. Application of finite element computations for the analysis of deformation and failure processes in real ceramic foams is time consuming. Therefore, the use of simplified periodic cell structure models for the assessment of elastic moduli and failure strength appears very attractive from the point of view of practical applications.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Doświadczalne wyznaczenie granicy plastyczności materiału kompozytowego "Stahl 1018" w podwyższonych temperaturach
Experimental Determination of the Yield Strength of the Composite Material "Stahl 1018" at Elevated Temperatures
Autorzy:: Arustamian, A.
Kalisz, D.
Tematy:: kompozyt polimerowy
kompozyt Stahl 1018
granica plastyczności
wytrzymałość mechaniczna
polymer composite
plasticity limit
mechanical strength; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/381566.pdf Link otwiera się w nowym oknie
Opis:: Praca zajmuje się badaniem wpływu temperatury na właściwości mechaniczne materiału kompozytowego MM "Stahl 1018". W pracy przedstawiono opis techniki wytwarzania kompozytu Stahl 1018 oraz metodykę prowadzonych badań laboratoryjnych. Analiza uzyskanych wyników na podstawie przeprowadzonych eksperymentów wykazała, że wraz ze wzrostem temperatury maleje granica plastyczności badanego materiału kompozytowego.
A theoretical and practical study of the effect of temperature on the mechanical properties of the composite material MM "Stahl 1018". Describes laboratory setting in which testing will be conducted, as well as describes a method of preparation and carrying out of the experiment. Also, the analysis of the results of the experiments, which showed that with increasing temperature decreases the yield strength of the material.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Effects of Waste Glass Powder on Subgrade Soil Improvement
Autorzy:: Javed, Syed Aaqib
Chakraborty, Sudipta
Tematy:: California Bearing Ratio (CBR)
Liquid Limit (LL)
Maximum Dry Density (MDD)
Optimum Moisture Content (OMC)
Plastic Limit (PL)
Soil Stabilization
Unconfined Compression Strength (UCS)
Waste Glass Powder; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1030256.pdf Link otwiera się w nowym oknie
Opis:: The weak soil is largely distributed worldwide and creates problems in constructing pavements, roadways, structures, irrigation systems and foundation works due to low shear strength and bearing capacity. The ways of improving soil is known as soil stabilization. Various soil stabilization techniques are using but none of them are cost effective and environmentally friendly way. The present study aims to effect of soil stabilization with waste glass powder which will reduce the cost and is environmentally friendly. To investigate the effect of glass powder in cohesive soil different types of index and geotechnical engineering tests are conducted and compared with the virgin soil. Glass powder was mixed with the soil samples by 2%, 4%, 6%, 8% and 10% of dry weight of soil to conduct the tests and to determine the optimum percentage of glass powder. The Liquid Limit (LL), Plastic Limit (PL) and Plasticity Index (PI) continuously decreased and found 33.9%, 18.4% and 15.5% respectively at 10% of glass powder. Maximum dry density (MDD) was increasing and found constant and Optimum Moisture Content (OMC) was decreasing when added glass powder. The both Unsoaked and Soaked California Bearing Ratio (CBR) was increasing with the addition of glass powder and found maximum value 22.5% and 10.4% respectively. Unconfined compressive strength (UCS) was increasing up to 8% of glass powder and found to 133.5 KN/m2 and then decreased to 119.7 KN/m2 when added 10% of glass powder. Shear strength parameter also increases with the increase of glass powder. The study found that the optimum percentage of glass powder is 8% of dry weight of soil.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Próba weryfikacji parametrów wytrzymałościowych odpadów powęglowych metodą granicznego stanu naprężenia
A trial of verification strength parameters of colliery spoils using limit stress state method
Autorzy:: Baran, P.
Zawisza, E.
Szymacha, A.
Tematy:: odpady powęglowe
graniczny stan naprężenia
parametry wytrzymałościowe
badania modelowe
colliery spoils
limit stress state
strength parameters
model tests; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/350404.pdf Link otwiera się w nowym oknie
Opis:: Przedmiotem artykułu jest weryfikacja wartości parametrów wytrzymałościowych odpadów powęglowych. Kąt tarcia wewnętrznego i spójność zostały wyznaczone za pomocą średniowymiarowego aparatu bezpośredniego ścinania oraz metodą analizy wstecznej problemu nośności granicznej skarpy modelowej. Na podstawie wyników badań i analiz otrzymane wartości parametrów wytrzymałościowych zostały użyte w metodzie granicznego stanu naprężenia. Obliczenia tą metodą pozwoliły uzyskać kształt zbocza i przebieg krzywej poślizgu w stanie granicznym dla dwóch par wspomnianych parametrów. Porównanie tych kształtów z badaniem modelowym pokazało, iż wartość spójności uzyskana w średniowymiarowym aparacie bezpośredniego ścinania jest o połowę zawyżona.
The subject of the paper is verification strength parameters of colliery spoils. Angle of internal friction and cohesion have been obtain using a middle-size shear box apparatus as well as back analysis in conjunction with a laboratory model test. The strength parameters obtained from laboratory tests and calculations have been use in limit stress state analysis. The analysis has enabled to obtain a shape of slope and position of slip surface in limit state for two pairs of strength parameters. A comparison between the shapes calculated and the shape from model test, revealed the value of cohesion obtained using the shear box apparatus is half overstate.
Dostawca treści:: Biblioteka Nauki

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