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Wyszukujesz frazę "size effect" wg kryterium: Temat


Wyświetlanie 1-15 z 15
Tytuł:
Size effect at testing strength properties of concrete
Autorzy:
Akram, Amanda
Powiązania:
https://bibliotekanauki.pl/articles/1955920.pdf
Data publikacji:
2021
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
concrete
size effect
tensile strength
Opis:
Various strength characteristics of concrete are considered as fracture parameters. The compressive strength of concrete is of paramount importance when designing concrete structures, whereas tensile strength of concrete is the basic property when estimating cracking resistance of a structure and analysing fracture processes in concrete. When testing the compressive strength of concrete, the results are dependent on the shape and dimensions of used specimens. Some findings reported in the literature suggest that size effect exists also when testing such fracture properties of concrete as tensile strength. Unfortunately this problem is much less recognized and described compared to size effect in compressive test results. In this paper, the experimental investigation is presented on how the length of cylindrical specimens influences the tensile splitting strength of concrete obtained by means of the Brazilian method. Additional variable parameters were: type of aggregate (natural gravel and crushed granite) and cement-water ratio (C/W = 1.8 and C/W = 2.6). In conducted laboratory experiments a higher splitting tensile strength of concrete was noted for all specimens with nominal dimensions of 150×150 mm, compared to specimens 150×300 mm in size, regardless of type of aggregate or cement-water ratio.
Źródło:
Budownictwo i Architektura; 2021, 20, 4; 37-45
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Importance of the Size of Local Government in Avoiding the Fiscal Distress - Empirical Evidence on Communes in Poland
Autorzy:
Galiński, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/16729115.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
fiscal distress
local government
size effect
Opis:
Theoretical background: In the literature on finance there are findings which examine reasons for the fiscal distress of units of the public sector, including local governments. However, this distress might be differently defined. Therefore, it determines both the approach to identify this phenomenon and the types of explanatory variables. Nevertheless, in the field of the business sector in the econometric models concerning the financial distress the size of the unit is considered. In this case there are also some possibilities to apply the correct proxy variable. This results from the fact that the size of local government might determine its fiscal capability as well as the level and structure of expenditures, which affect fiscal distress. Purpose of the article: The aim of this paper is to examine the influence of the size of the local government on the probability of the decrease of the exposure to the fiscal distress. Research methods: The author reviewed the literature in the field of the fiscal distress and introduced a multi-criteria decision analysis as well as a logistic regression modelling to examine this. The research procedure also required the use of the linear ordering to construct the dependent variable of the fiscal distress in order to analyse the “size effect” on the fiscal distress. Main findings: Fiscal distress of local governments is a core issue, which should be constantly analysed. It depends on the financial, economic, social and even political aspects. To identify exposure to this distress the TOPSIS method can be used. However, the fiscal distress can be affected by the size of the unit, which influences lots of budgetary categories. Due to the specificity of dependent and independent variables in the econometric models the “size effect” might be represented through the level of the population or the assets. Using the ordinal logistic regression in the research, the authors should consider that this effect can differ between the units with the disparate exposure. So, the partial proportional odds models can be required. Thus, the growth of the size of the unit, measured by the population, increases the odds of reaching very low exposure to fiscal distress. Simultaneously, there are some other important issues which should be included in this type of research.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia; 2022, 56, 5; 101-113
0459-9586
2449-8513
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ubiquitiformal fracture energy
Autorzy:
Ou, Z.-C.
Yang, M.
Li, G.-Y.
Duan, Z.-P.
Huang, F-L.
Powiązania:
https://bibliotekanauki.pl/articles/280189.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
fractal
ubiquitiform
fracture energy
size effect
Opis:
The ubiquitiformal fracture energy is proposed in the paper and its explicit expression is obtained. Moreover, the numerical results for concrete are found to be in good agreement with those for the critical strain energy release rate. The discrepancy between the numerical results of the traditional fracture energy and the critical strain energy release rate can be explained reasonably, which implies that the ubiquitiformal fracture energy should be taken as an available fracture parameter of materials. Finally, it is numerically found for some concrete that there is not size effect for the ubiquitiformal fracture energy.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 3; 1101-1108
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On some problems in determining tensile parameters of concrete model from size effect tests
Autorzy:
Marzec, Ireneusz
Bobiński, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/260481.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
concrete
size effect
fracture energy
elasto-plasticity
XFEM
Opis:
The paper presents results of numerical simulations of size effect phenomenon in concrete specimens. The behaviour of in-plane geometrically similar notched and unnotched beams under three-point bending is investigated. In total 18 beams are analysed. Concrete beams of four different sizes and five different notch to depth ratios are simulated. Two methods are applied to describe cracks. First, an elasto-plastic constitutive law with a Rankine criterion and an associated flow rule is defined. In order to obtain mesh independent results, an integral non-local theory is used as a regularisation method in the softening regime. Alternatively, cracks are described in a discrete way within Extended Finite Element Method (XFEM). Two softening relationships in the softening regime are studied: a bilinear and an exponential curve. Obtained numerical results are compared with experimental outcomes recently reported in literature. Calculated maximum forces (nominal strengths) are quantitatively verified against experimental values, but the force – displacement curves are also examined. It is shown that both approaches give results consistent with experiments. Moreover, both softening curves with different initial fracture energies can produce similar force-displacement curves.
Źródło:
Polish Maritime Research; 2019, 2; 115-125
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of dynamic growth of a micro-scaled void based on strain gradient elasto-plasticity
Autorzy:
Ma, Xinbing
Liu, Jinxing
Wang, Jiadong
Pan, Hao
Powiązania:
https://bibliotekanauki.pl/articles/1839598.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dynamic void growth
size effect
inertia
thermal softening
Opis:
Void initiation and growth serve as an important mechanism in ductile failures in metals. Particularly, on the micron-level, the extra hardening effect associated with strain gradient is accounted for by adopting strain gradient elasto-plasticity instead of the conventional plasticity. Effects of inertial, strain gradient hardening and thermal softening are formulated analytically for the case where a spherical void expands under external hydrostatic stress. As demonstrated by our results, the inertia effect firstly tends to hinder but then promotes the void growth. The threshold stress required for rapid void growth is lifted due to extra hardening of strain gradient so that the growth of a smaller void is delayed more remarkably. A considerable thermal softening phenomenon is observed here, which is caused by plastic work during the deformation process. The final void growth rate is mainly related to the maximum loading, which is consistent with the prediction based on the classical plastic theory.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 4; 927-941
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of pre-tension on torsion of microscale Cu wires: a study via strain gradient theory
Autorzy:
Ma, Xinbing
Liu, Jinxing
Powiązania:
https://bibliotekanauki.pl/articles/280360.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonproportional loading
strain gradient plasticity
size effect
cyclic response
Opis:
Nonproportional plastic deformations on the microscale are an emerging topic. A simplified theory of strain gradient elasto-plasticity is developed to study the evolution of yield strength in a copper wire sequentially experiencing tension and torsion. The pre-tension deformation and stress are inherited to the upcoming torsion process, resulting in a nonproportional loading condition. With consideration of the extra hardening effect due to strain gradient, pre-tension weakens the extra hardening effect of the strain gradient and the dependence on the wire radius. Cyclic torsion behavior is also investigated. Anomalous Bauschinger effect and plastic softening are found.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 4; 1055-1065
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue life prediction of aluminium profiles for mechanical engineering
Autorzy:
Tomaszewski, T.
Sempruch, J.
Powiązania:
https://bibliotekanauki.pl/articles/281070.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
aluminium profile
high-cycles fatigue
mini specimen
size effect
Opis:
The study presents a method to determine the σa − N curve (high cycle fatigue) for profiles made of AW-6063 T6 aluminium alloy. Experimental material data for a mini specimen taken directly from the tested item and selected empirical correlations allowing for a size effect have been used. A model yielding the lowest relative error of estimating the fatigue life is presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 497-507
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2D Lattice Model for Fracture in Brittle Materials
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/241484.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
beam
brittle material
discrete method
fracture
lattice model
size effect
Opis:
The numerical simulations show the potential of a lattice discrete approach to model fracture during brittle materials in different two-dimensional quasi-static processes of loading behaviour. The 2D calculations were carried out for brittle specimens subject to uniaxial compression, uniaxial extension and shear. The effect of the specimen size on the global stress-strain diagram during uniaxial tension was also investigated. The advantages and disadvantages of the model were outlined.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 2; 137-154
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of creep failure probability on the size of metallic specimens
Autorzy:
Nowak, K.
Powiązania:
https://bibliotekanauki.pl/articles/387437.pdf
Data publikacji:
2013
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
size effect
creep damage
cellular automata
efekt rozmiarowy
zniszczenie przy pełzaniu
pełzanie
Opis:
The occurrence of statistical size effect is considered for damage in creep conditions. The numerical and experimental analysis have been performed. The obtained results are ambiguous. Numerical models confirm the scale effect which can be statistical or deterministic one. But this effect has no experimental verification. It may suggest that the weakest link model cannot be applied in creep conditions. Explanation of this needs further investigations.
Źródło:
Acta Mechanica et Automatica; 2013, 7, 3; 166-169
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The experimental tool for micro-extrusion of metals
Autorzy:
Piwnik, J.
Mogielnicki, K.
Gabrylewski, M.
Baranowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/381943.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microforming
microextrusion
size effect
experimental tool
mikroformowanie
mikrowyciskanie
efekt skali
narzędzie doświadczalne
Opis:
In paper the technological tools requirements, used for micro-extrusion of metals in cold and warm conditions are presented. The constructive principles for the micro-tools are also described. The influence of the size effect in a workpiece and a tool top layers roughness form on extrusion processes in microscale are showed. The tool, designed to an experimental verification of the size effect influence, in a tool roughness form, on the metal rod forward extrusion are presented. This tool is made in the form of two halves, joined together by the pegs and screws. It has bored two dies profiles with the same dimensions, the only difference is a degree of the containers roughness. That solution gives a possibility to specify the influence of the tool roughness degree on the extrusion forces, deformation process and a product quality. Described tool was designed in such a way to manufacture it with using conventional machining equipment.
Źródło:
Archives of Foundry Engineering; 2011, 11, 2 spec.; 195-198
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the size effect of auxetic cellular materials
Autorzy:
Janus-Michalska, M.
Powiązania:
https://bibliotekanauki.pl/articles/265410.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
negative Poissons ratio
auxetic structures
size effect
właściwości sprężyste
próba ścinania
kompresja
Opis:
The objective of this paper is to investigate the effects of scale of an auxetic cellular material sample on the evaluation of elastic properties. Size and boundary effects are studied in detail. This is achieved by conducting computer simulations of the auxetic structure under the typical loading exerted by the compression and simple shearing test performed by means of ABAQUS FEA. The material microstructure is discretized by the plane network of Timoshenko beam elements. The results of the studies give insight to the scale effects. Structures with designed properties can be potentially used for engineering applications.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 749-757
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon nanotubes with controlled length – preparation, characterization and their cytocompatibility effects
Autorzy:
Cendrowski, K.
Jedrzejczak-Silicka, M.
Powiązania:
https://bibliotekanauki.pl/articles/778531.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Multiwalled carbon nanotubes
cutting carbon nanotubes
size effect
mitochondrial activity
biocompatibility
apoptosis
necrosis
Opis:
Multiwalled carbon nanotubes (MWCNTs) have attracted huge attention due to their multifunctionality. Their unique properties allows for covalent and noncovalent modifi cations. The most simple method for functionalization of carbon nanotubes is their decoration with the oxygen containing moieties which can be further simultaneously functionalized for design of new class carriers for targeting and imaging. Here, we present methodology for chopping nanotubes, characterization of MWCNTs, the effect of size on the biocompatibility in culture of L929 mouse fi broblasts using WST-1, LDH and apoptosis assays. The analysis provides the optimal carbon nanotubes length and concentration which can be used for functionalization in order to minimize the effect of the secondary agglomeration when interacting with cells.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 2; 71-79
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size Effects in Problems of Footings on Sand within Micro-Polar Hypoplasticity
Autorzy:
Tejchman, J.
Górski, J.
Powiązania:
https://bibliotekanauki.pl/articles/241079.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
footing
micro-polar hypoplasticity
sand
shear localization
size effect
stratified sampling
void ratio
Opis:
Numerical FE investigations of size effects in problems of footings on sand were performed. Micro-polar hypoplastic constitutive model was used to describe a mechanical behaviour of a cohesionless granular material during a monotonic deformation path. The FE analyses were carried out with three different footing widths. In deterministic calculations, a uniform distribution of initial void ratio was used. In statistical calculations, initial void ratios took the form of random spatial fields described by a truncated Gaussian random distribution. In order to reduce the number of stochastic realizations without sacrificing the accuracy of the calculations, a stratified sampling method was applied. The numerical results were compared with corresponding laboratory tests by Tatsuoka et al (1997). The numerical results show that the bearing capacity of footings decreases with increasing specimen size. If the initial void ratio is stochastically distributed, the mean bearing capacity of footings may be larger than the deterministic value. The statistical size effect is smaller than the deterministic one.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2008, 55, 3-4; 95-124
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Country selection strategies for portfolio management
Autorzy:
Zaremba, Adam
Konieczka, Przemysław
Powiązania:
https://bibliotekanauki.pl/articles/950658.pdf
Data publikacji:
2015
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
value effect
size effect
momentum
volatility effect
anomaly of low risk
inter-market effects
cross-section analysis of returns
factor returns
international diversification
asset pricing
Opis:
This study examines 16 country selection strategies based on inter-market value, size, momentum, quality and volatility effects. We investigate a sample of 78 countries for the period 1999-2014. Having considered country-specific dividend tax rates, market liquidity and openness for investment flows we can state that chosen strategy based on earnings to price ratio proves useful for investors. Momentum strategies should be approached with caution, as they appear effective only in small markets and may lead to loses in large markets. Selecting low leveraged and illiquid countries also proves beneficial. The relation between volatility displays different characteristics for open and closed economies.
Źródło:
Financial Sciences. Nauki o Finansach; 2015, 1(22); 101-119
2080-5993
2449-9811
Pojawia się w:
Financial Sciences. Nauki o Finansach
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nośność na przebicie krępych płyt żelbetowych – badania i analiza metodą S-T
Punching shear behavior of thick reinforced concrete slabs according to Strut-and-Tie model
Autorzy:
Urban, T.
Krakowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/391037.pdf
Data publikacji:
2014
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
metoda kratownicowa (strut-and-tie)
przebicie osiowe
smukłość ścinania
fundament
efekt skali
Strut-and-tie model
punching shear
shear slenderness
footing
size effect
Opis:
W pracy przedstawiono próbę analizy nośności na przebicie płyt krępych za pomocą metody kratownicowej (strut-and-tie, S-T). Procedura obliczeniowa została porównana z wynikami własnych badań eksperymentalnych. Zakres analizy obejmuje wyłącznie elementy bez zbrojenia poprzecznego obciążone osiowo symetrycznie.
The punching shear behavior of thick reinforced concrete slabs was analyzed in this paper by using strut-and-tie model (S-T). Calculating procedures were compared to our own experimental test results. The analyzed elements were subjected to symmetric loading and without shear reinforcement.
Źródło:
Budownictwo i Architektura; 2014, 13, 3; 183-191
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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