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Wyświetlanie 1-15 z 57
Tytuł:
Analysis of strain localization in porous media with transversely isotropic elasticity under undrained conditions
Autorzy:
Zhang, Y. Q.
Wang, L. Z.
Pang, M.
Fan, L. F.
Powiązania:
https://bibliotekanauki.pl/articles/949143.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
porous medium
strain localization
transverse isotropic elasticity
undrained condition
pore fluid compressibility
Opis:
The properties of strain localization for elastic-plastic porous media with transversely isotropic elasticity under undrained conditions are investigated. Under non-associated plasticity and tri-axial stress states, the conditions for strain localization of elastic-plastic porous media are derived, in which the effects of deviation from isotropic elasticity and pore fluid compressibility are included. Based on the Mohr-Coulomb yield criterion, the influences of the deviation from isotropic elasticity and pore fluid compressibility on the direction angle of localized band initiation and the corresponding critical hardening modulus for the case of plane strain are discussed. As a result, the properties of strain localization are dependent upon the deviation from isotropic elasticity and pore fluid compressibility. The deviation from isotropic elasticity and pore fluid compressibility has significant impacts on the direction angle of localized band initiation and the corresponding critical hardening modulus.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 199-211
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Detonation Pressure and Velocity of Explosives with Micrometer Aluminum Powders
Autorzy:
Zhang, Q.
Chang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358334.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
aluminized explosives
detonation pressure
nonideal explosives
detonation velocity
Opis:
The data reported shows that the Chapman-Jouguet (CJ) detonation parameters of non-ideal explosives calculated from existing thermodynamic computer codes are significantly different from experimental results. We use CJ detonation theory to present a new approach predicting detonation pressure and velocity of aluminized explosives by thermodynamic detonation theory. There is no need to use the assumption of full and partial equilibrium of aluminum powder in reaction zones in the new approach. In this work the best agreement with experimental data was obtained by adjusting the parameter k in the Becker- Kistiakosky-Wilson equations of state (BKW-EOS). The detonation pressure and velocity values calculated by the present method agree well with the experimental results. All of the deviations for the calculated pressures of aluminized explosives are less than 9% and those for the detonation velocities are less than 7%.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 1; 77-86
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Predictive Method for the Heat of Explosion of Non-ideal Aluminized Explosives
Autorzy:
Zhang, Q.
Chang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358737.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
aluminized explosives
heat of explosion
thermodynamic
nonideal explosives
high energy materials
Opis:
The heat of explosion is one of the most important thermodynamic parameters of aluminized explosives. Two improvements in numerical calculations to predict the behaviour of the explosion of non-ideal aluminized explosives were completed in this work. The chemical reaction between aluminum and the C-J detonation products of high energy ingredients was determined and the equation of state for the detonation products of high energy ingredients was revised. The constant k in the BKW equation was revised to obtain perfect results for predicting the C-J parameters for high energy ingredients. The predicted results show that the heats and temperatures of aluminized explosives become maximized when the mass fraction of aluminum powder is 30%, which is in good agreement with the results obtained by empirical formulae.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 4; 541-554
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and optimization design of offshore drilling seal
Autorzy:
Zhang, Y.
Zhang, X.
Chang, X.
Wu, Q.
Powiązania:
https://bibliotekanauki.pl/articles/260627.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
offshore drilling
design optimization
seals
finite element analysis
MATLAB
Opis:
Three-cone bit is the key equipment in the exploration of the oil in offshore drilling and exploration, the bearing system and the seal system are the critical components for the bit. Especially in the offshore drilling environment, the seal design need to be carefully considered. A multi-objective optimization design including orthogonal design method and F-test with finite element analysis for a three-cone bit seal is proposed. Firstly, the calculation method of optimization targets are given, including the minimization of maximum contact pressure and leakage rate analyzed by ANSYS and MATLAB respectively, to maximize seal life and reliability. Then, an orthogonal experiment approach is used to investigate the effects of the eleven parameters on the seal performance, and the influence degrees of the seal factors on the optimization targets have been confirmed by F-test, and the reasonable factors can be determined by the trend of the targets. Finally, in order to validate the analysis results, a new seal was designed and tested on a seal tester compared to the previous seal. In this test, the seal maximum interface temperature that reflects the position of maximum contact pressure can be obtained by using three high precision thermocouples. Both the experiment results and the numerical analyses proved that the maximum contact pressure and leakage rate of the improved seal have been reduced compared to the previous.
Źródło:
Polish Maritime Research; 2017, S 3; 72-78
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption of congo red from aqueous solutions by porous soybean curd xerogels
Autorzy:
Zhang, Z.
Li, Y.
Du, Q.
Li, Q.
Powiązania:
https://bibliotekanauki.pl/articles/778311.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Soybean curd
Congo red
Adsorption
Kinetics
Thermodynamics
Opis:
Soybean curd is a very popular food containing high-quality protein, polyunsaturated fats, vitamins, minerals and other nutrients. This study aims to prepare porous soybean curd xerogels via a vacuum freeze drying method and uses them as adsorbents to remove congo red from aqueous solutions. The morphology and functional groups of the soybean curd xerogels were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The adsorption properties of congo red onto the soybean curd xerogels were carried out through investigating the influencing experimental parameters such as the drying method, solution pH, adsorbent dose, contact time and temperature. The results showed that the adsorption isotherm data were fitted well to the Freundlich isotherm. Adsorption kinetics of congo red onto the soybean curd followed the pseudo-second-order kinetic model. The thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were also determined.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 3; 95-102
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3-aminopropyltriethoxysilane functionalized nanoscale zero-valent iron for the removal of dyes from aqueous solution
Autorzy:
Zhang, J.
Liu, Q.
Ding, Y.
Bei, Y.
Powiązania:
https://bibliotekanauki.pl/articles/779270.pdf
Data publikacji:
2011
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
3-aminopropylotrietoksysilan
żelazo zerowartościowe
separacja magnetyczna
3-aminopropyltriethoxysilane
nano zero-valent iron
acid brilliant scarlet GR
reactive brilliant red K-2BP
magnetic separation
Opis:
Batch studies were conducted to investigate the potential of 3-aminopropyltriethoxysilane modified nano zero-valent iron (APS-NZVI) to adsorb two dyes (acid brilliant scarlet GR and reactive brilliant red K-2BP) from aqueous solution. APS-NZVI showed good adsorption performance for two dyes. Under the adsorption conditions of pH 4.5, initial concentration was 100 mg/L, and time=4h, the maximum adsorption capacities of APS-NZVI were 121.06 mg/g for acid brilliant scarlet GR and 191.5 mg/g for reactive brilliant red K-2BP, respectively. The results revealed that the adsorption behavior of the dyes on the nano-particles fitted well with the Langmuir model and the sorption kinetics fits well the pseudo-second-order rate equation.
Źródło:
Polish Journal of Chemical Technology; 2011, 13, 2; 35-39
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on relationship between carbon dioxide emissions, imports, exports, and population in China
Autorzy:
Jin, Q.-Y.
Zhang, J.
Gao, Y.-Q.
Su, X.
Fu, Y.-S.
Powiązania:
https://bibliotekanauki.pl/articles/207318.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
population statistics
carbon dioxide
global warming
carbon dioxide emissions
total carbon
statystyki ludności
dwutlenek węgla
globalne ocieplenie
emisja dwutlenku węgla
węgiel całkowity
Opis:
Empirical relationships between carbon dioxide emission, imports, exports, and population have been investigated. An empirical model with carbon dioxide emissions, structure and scale of import and exports, populations was built Using ridge regression analysis and observed data from 1985 to 2006 in China, we examined the relationship between each part of carbon dioxide emission and corresponding coefficients, including GIV (gross imports value), GXV (gross exports value), and P (populations). The results have shown that the increasing trend in TCOE (total carbon dioxide emissions) was determined by the exports, while its standard level is determined by population. Increasing the imports may reduce TCOE. Considering working to expand economy, the best ways for China to reduce TCOE are to introduce advanced technology and take actions to guarantee strict execution of cut-emission policy. Although the increasing imports also can reduce TCOE, it is not reasonable for the global cut-emission policy. To control population is not applicable as the immense population base, so government's publicity for low-carbon live is a necessary and feasible way to reduce carbon dioxide emission.
Źródło:
Environment Protection Engineering; 2014, 40, 2; 75-85
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability analysis for multi-state system based on triangular fuzzy variety subset bayesian networks
Analiza niezawodności systemu wielostanowego z zastosowaniem sieci bayesowskich opartych na rozmytych podzbiorach zmienności opisanych przez trójkątną funkcję przynależności
Autorzy:
He, Q.
Zha, Y.
Zhang, R.
Sun, Q.
Liu, T.
Powiązania:
https://bibliotekanauki.pl/articles/302183.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
teoria zbiorów rozmytych
system wielostanowy
sieć bayesowska
wypadek podczas ruchu wózka windy
analiza niezawodności
reliability analysis
fuzzy set theory
Multi-State System
Bayesian network
elevator free movement accident
Opis:
W niniejszej pracy zaproponowano nową metodę analizy niezawodności systemów wielostanowych wykorzystującą sieci Bayesa (BN) oparte na rozmytych podzbiorach zmienności opisanych za pomocą trójkątnej funkcji przynależności. Metoda ta uwzględnia rozmyty charakter danych dotyczących uszkodzeń, wielostanowość systemu oraz zmienność prawdopodobieństwa wystąpienia uszkodzenia w czasie. BN, które znalazły zastosowanie w modelowaniu i metodach obliczeniowych, wykorzystuje się także do analizy niezawodności. W przedstawionych badaniach, analizę BN uzupełniono o elementy teorii zbiorów rozmytych wykorzystując do opisu prawdopodobieństwa wystąpienia uszkodzenia, podzbiory zmienności opisane przez trójkątną funkcję przynależności. Niepewność zależności logicznej pomiędzy awariami reprezentowanymi przez różne węzły sieci opisano za pomocą tabel rozmytego prawdopodobieństwa warunkowego. W pierwszej kolejności analizowano prawdopodobieństwo uszkodzenia każdego korzenia (węzła głównego) w funkcji czasu. Następnie, wyznaczono trójkątny rozmyty podzbiór zmienności, za pomocą którego opisano rozmyte prawdopodobieństwo uszkodzenia węzłów głównych. Podzbiór ten wykorzystano do analizy niezawodności systemu wielostanowego przy pomocy rozmytych BN. Artykuł kończy opis wypadku podczas ruchu wózka windy szybkobieżnej, który potwierdza skuteczność i możliwość praktycznego wykorzystania proponowanej metody. Wyniki pokazują, że proponowane podejście może skutecznie rozwiązywać na wczesnym etapie problemy związane z niepewnością informacji oraz wielostanowością systemu.
In this paper, a novel reliability analysis method for multi-state system is proposed on the basis of triangular fuzzy variety subset Bayesian network (BN). The method considers fuzziness, multi-state, and variety of failure probability over time. With advantages in modeling and computation, the BN is utilized for reliability analysis. Fuzzy set theory is introduced into the BN analysis by using triangular fuzzy variety subset to describe failure probability. The uncertainty of fault logical relationship between different nodes is described through fuzzy conditional probability tables. As a function of time, the failure probability of each root node is analyzed first. Subsequently, the triangle fuzzy variety subset is established to describe the fuzzy failure probability of root nodes. This subset is applied to analyze the reliability of multi-state system fuzzy BN. Finally, a case study on the car free movement accident of flexible high-speed elevator lift system is used to demonstrate the effectiveness and practicality of the proposed method. Results show that the proposed approach could effectively address the problems on information uncertainty and multi-state in the early stage.
Źródło:
Eksploatacja i Niezawodność; 2017, 19, 2; 158-165
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of provenance and water stress on biomass and polyphyllin content in the medicinal plant Paris polyphylla Smith var. yunnanensis
Autorzy:
Wu, X.
Zuo, .
Zhang, Q.
Wang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/12304075.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
plant cultivation
Paris polyphylla
medicinal plant
herbal plant
water stress
biomass
polyphyllin content
Opis:
Water stress and provenance could affect the secondary metabolites synthesis and accumulation in herbs. Thus, this study explored the effect of soil water moisture and provenance on the growth of Paris polyphylla Smith var. yunnanensis (PPY). Three provenances (Jinping, Luquan and Weixi in Yunnan, China) of PPY samples were grown in different soil water moisture conditions [0.80, 0.70 and 0.50 field capacity (FC)] during Dec. 2015 to Sep. 2017. Results showed that the highest biomass weight was presented in 0.70 FC for Luquan and Weixi samples. Biomass weight for Jinping provenance presented a decreasing tendency with the decreased soil water moisture and the highest biomass were shown in 0.80 FC. However, quantitative analysis revealed that the total content of polyphyllin increased with decreasing the soil water moisture for Jinping and Weixi samples. The highest total content of polyphyllin in rhizome was inclined to show in Jinping samples, while the stem and leaf tissues were shown in Weixi samples. Additionally, results of ANOVA combined with PCA indicated that the difference among these three provenances were significant. Correlation analysis results revealed that 0.50 FC induced the competitive relationship occurrence for polyphyllin distribution. Thus, 0.70 FC was the most suitable soil-water condition for PPY growth. Besides, provenance collected from Jinping could consider as a good quality germplasm. Consequently, this study might provide a preliminary foundation for irrigation project formulated and provenance screened for PPY cultivation.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 2; 171-191
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pre-concentration of graphite and LiCoO2 in spent lithium-ion batteries using enhanced gravity concentrator
Autorzy:
Zhu, X,-N.
Tao, Y.-J.
He, Y.-Q.
Zhang, Y.
Sun, Q.-X.
Powiązania:
https://bibliotekanauki.pl/articles/109609.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
spent lithium-ion batteries
electrode material
resource utilization
pre-concentration
enhanced gravity concentrator
Opis:
The pre-concentration of electrode material of spent lithium-ion battery has great significance on the resource utilization and environmental protection. The feasibility of separation of graphite and LiCoO2 based on density difference using the enhanced gravity concentrator was verified in this paper. Combustion characteristics of LiCoO2 and graphite were used to propose a simple evaluation index of separation efficiency. Separation tests were carried out to specify the influence of operating parameters on the separation efficiency. Moreover, the effect of particle size on the separation performance was studied. Combustion characteristics results showed that mass loss of graphite was much greater than that of LiCoO2. Thus, mass loss were used to evaluate the purity of product. Effective separation of graphite and LiCoO2 was achieved by the enhanced centrifugal separator. Separation results showed that increasing centrifugal force decreased the overflow yield and increased the graphite content of the overflow stream. In addition, yield of overflow grew an increase in fluidization water pressure, while the purity of graphite in overflow decreased. The effect of particle size on the separation efficiency was also significant, the separation efficiency decreased with the decreasing of particle size.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 293-299
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue Behavior and Mechanism of FV520B-I Owing to the Effect of Loading Frequency on the Fatigue Property in HCF and VHCF Regime
Autorzy:
Wang, J.
Zhang, Y.
Shi, B.
Zhao, Q.
Sun, Q.
Zhang, Z.
Lu, H.
Powiązania:
https://bibliotekanauki.pl/articles/353784.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrahigh loading frequency
FV520B-I
fatigue strength
fatigue conversion model
Opis:
Fatigue property of FV520B-I is affected by the ultrahigh loading frequency significantly, and the ultrasonic fatigue experimental data can’t be employed directly to analyze the fatigue failure in the actual remanufacturing engineering. However few theories about the effect of loading frequency on the fatigue property of FV520B-I has ever been proposed. In this paper, both ultrasonic experiment and conventional experiment are conducted out to obtain the fatigue data. The effect of loading frequency on the fatigue data distribution is discussed firstly, its fatigue limit declines with the increase of the loading frequency. Then the fracture surface observations are captured, the fatigue property and fatigue behavior mechanism of FV520B-I is examined by analyzing the fracture surface features, crack initiation and failure observations. A new material frequency correction factor is proposed and introduced to eliminate the influence of the loading frequency on the FV520B-I fatigue property. FV520B-I empirical fatigue life conversion model and fatigue strength conversion model are established with comprehensive use of a fitting algorithm based on the combination of experimental data and classic formula. A clear understand of the effect of loading frequency on the fatigue property of FV520B-I is novel and has an important significance in guaranteeing the accuracy of the actual fatigue analysis of FV520B-I in the remanufacturing engineering.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 347-357
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Population diversity maintenance in brain storm optimization algorithm
Autorzy:
Cheng, S.
Shi, Y.
Qin, Q.
Zhang, Q
Bai, R.
Powiązania:
https://bibliotekanauki.pl/articles/91571.pdf
Data publikacji:
2014
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
brainstorm
optimization algorithm
convergence
divergence
brainstorm optimization
BSO
swarm intelligence
BSO algorithm
Opis:
The convergence and divergence are two common phenomena in swarm intelligence. To obtain good search results, the algorithm should have a balance on convergence and divergence. The premature convergence happens partially due to the solutions getting clustered together, and not diverging again. The brain storm optimization (BSO), which is a young and promising algorithm in swarm intelligence, is based on the collective behavior of human being, that is, the brainstorming process. The convergence strategy is utilized in BSO algorithm to exploit search areas may contain good solutions. The new solutions are generated by divergence strategy to explore new search areas. Premature convergence also happens in the BSO algorithm. The solutions get clustered after a few iterations, which indicate that the population diversity decreases quickly during the search. A definition of population diversity in BSO algorithm is introduced in this paper to measure the change of solutions’ distribution. The algorithm’s exploration and exploitation ability can be measured based on the change of population diversity. Different kinds of partial reinitialization strategies are utilized to improve the population diversity in BSO algorithm. The experimental results show that the performance of the BSO is improved by part of solutions re-initialization strategies.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2014, 4, 2; 83-97
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Interaction of Water with Glycine: A Combined Inelastic Neutron Scattering and Raman Spectra Studies
Autorzy:
Zhang, P.
Zhang, Y.
Han, S.
Yan, Q.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/2044762.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.20.Ng
87.64.Je
25.40.Fq
82.30.Rs
Opis:
The vibrational dynamics of water around glycine was investigated by using Raman spectroscopy and inelastic neutron scattering. Experiments of deuterated glycine versus deuterium were performed as comparison. The study shows that for glycine, the exchange of proton-deuteron on the active NH$\text{}_{3}^{+}$ side was easy, whereas there was hardly exchange on the CH$\text{}_{2}$ side. Comparing different proportion of glycine vs. water molecules we obtained that the presence of water hardly changes the main features of glycine illustrating its hydrophobic character. The intralayer hydrogen bonds of glycine crystal are difficult to be replaced due to its stronger bond than water.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 399-404
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Constitutive model for time-dependent ratchetting of SS304 stainless steel: simulation and its finite element analysis
Konstytutywny model zależnego od czasu zjawiska ratchetingu dla stali SS304 – symulacja i analiza metodą elementów skończonych
Autorzy:
Jiang, X.
Zhu, Y.
Hong, J.
Zhang, Y.
Kan, Q.
Powiązania:
https://bibliotekanauki.pl/articles/280590.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ratchetting
time-dependence
constitutive model
finite element method
Opis:
Time-dependent ratchetting behaviour of SS304 stainless steel was experimentally conducted at room temperature and 973K. The material shows distinct time-dependent deformation. However, under cyclic stressing with a certain peak/valley stress hold and at 973K, more significant time-dependent inelastic behaviour was observed. Based on the Abdel-Karim-Ohno nonlinear kinematic hardening rule with the static recovery term, a time-dependent hardening rule incorporating an internal variable in the dynamic recovery term of the back stress is proposed to reasonably describe the evolution behaviour of time-dependent ratchetting with a certain peak/valley stress hold and at high temperature. Simultaneously, the proposed model is implemented into the ANSYS finite element package by User Programmable Features (UPFs). It is shown that the customized ANSYS model exhibits better performance than the reference model, especially under cyclic stressing with the certain peak/Valley stress hold and at high temperature.
W pracy przedstawiono wyniki badań eksperymentalnych nad zależnym od czasu procesem zmęczeniowym typu ratcheting przeprowadzonych w temperaturze pokojowej oraz podwyższonej do 973K. Materiał wykazał wyraźnie zależną od czasu funkcję deformacji. Podczas cyklicznego obciążania przy zadanych wartościach min/max naprężeń w temperaturze 973K zaobserwowano silnie nieliniowe i zależne od czasu zachowanie się badanej stali. Do wyjaśnienia tego zjawiska, zwanego ratchetingiem zależnym od czasu, wykorzystano model umocnienia materiału oparty na nieliniowej formule kinematycznego umocnienia Abdela-Karima-Ohno ze statycznym członem odprężania. Model ten zmodyfikowano, wprowadzając wewnętrzną zmienną w dynamicznym członie odprężania przy obciążeniu powrotnym. Jednocześnie zaproponowany model wdrożono do systemu ANSYS poprzez zastosowanie pakietu User Programmable Features (UPFs). Wykazano, że taka modyfikacja systemu ANSYS charakteryzuje się lepszym działaniem w stosunku do standardowego oprogramowania. Jest to szczególnie zauważalne dla symulacji cyklicznego obciążenia stali w podwyższonej temperaturze.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 63-73
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Evidence for Jahn-Teller Transition in a Fe(II)Fe(III) Bimetallic Oxalate
Autorzy:
Tang, G.
He, Y.
Xu, F.
Zhang, Q.
Powiązania:
https://bibliotekanauki.pl/articles/1400401.pdf
Data publikacji:
2013-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
76.80.+y
Opis:
Bimetallic oxalate ${[N-(n-C_4H_9)_4][FeFe(C_2O_4)_3]}_{n}$ has been investigated by the Mössbauer spectroscopy. The Mössbauer studies confirm that high-spin Fe(III) (S=5/2) and Fe(II) (S=2) ions are present in the compound. These spectra above 60 K consist of three quadrupole doublets, indicating that there are three different Fe sites in the material. The Mössbauer results reveal that spontaneous magnetization of Fe(II) sublattices increases more steeply than that of Fe(III) sublattices as the temperature decreases from $T_{C}$. Great increase of quadrupole splitting at 50 K provides compelling evidence for the predicted Jahn-Teller transition.
Źródło:
Acta Physica Polonica A; 2013, 123, 1; 118-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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