355 results on '"Cyclic model"'
Search Results
2. A new cyclic model for FRP‐confined rubberized concrete.
- Author
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Raffoul, Samar, Margarit, David Escolano, Garcia, Reyes, Guadagnini, Maurizio, and Pilakoutas, Kypros
- Subjects
- *
FIBER-reinforced plastics , *RUBBER , *CONCRETE , *CONSTRUCTION materials , *CYCLIC loads , *FIBER-reinforced concrete - Abstract
This article proposes a new constitutive model for the cyclic behavior of rubberized concrete confined with fiber‐reinforced polymer (FRP) sheets. The model is calibrated with experimental results from 18 confined rubberized concrete (CRuC) cylinders tested in cyclic compression. The cylinders had 60% total aggregate volume replacement with recycled tyre rubber. Parameters investigated include the type of confining material (Carbon or Aramid FRP) and number of layers (two, three, or four). The results indicate that using FRP confinement leads to a strong (up to 100 MPa) and highly deformable (axial strains up to 7%) rubberized concrete that can be used in structural applications. The proposed constitutive model predicts accurately the material response under cyclic loading and can thus be used for design/analysis of highly deformable components made of FRP CRuC. This article contributes toward the development of advanced constitutive models for FRP CRuC, thus promoting the wider use of recycled materials in construction industry. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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3. FringeNet: A cyclic U-Net model with continuity imposed hybrid cyclic loss for demodulation of isochromatics in digital photoelasticity.
- Author
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M. S., Vishnu Mohan, M. P., Hariprasad, and Menon, Vivek
- Subjects
- *
PHOTOELASTICITY , *SIGNAL-to-noise ratio , *DEMODULATION , *IMAGE processing , *DIGITAL learning - Abstract
This study introduces FringeNet, an innovative deep learning-based cyclic model to enhance the fringe order demodulation from single isochromatic images. A Continuity-Imposed Hybrid Cyclic Loss (CHCL) function, which combines Mean Squared Error (MSE), Structural Similarity Index (SSIM), Peak Signal-to-Noise Ratio (PSNR), and a continuity loss is proposed for optimizing multiple objectives, while enforcing the fringe order continuity in the isochromatic data. The proposed FringeNet is trained using available open-source ischromatic image dataset and the effectiveness of the model is validated using realistic experimental isochromatics. The FringeNet demonstrates a 92.4% improvement in MSE over existing methods, indicating substantial gains in predictive accuracy and model robustness. Additionally, a 16.19% enhancement in PSNR is observed, highlighting superior fidelity compared to existing approaches. The cyclic model employed in FringeNet represents a significant advancement in enhancing the deep learning-based predictive modeling used in the field of digital photoelasticity. • FringeNet: A novel deep learning cyclic model for fringe order demodulation from isochromatic images. • CHCL: Custom loss function combining MSE, SSIM, PSNR, and continuity loss to improve model performance. • Validation of FringeNet using realistic experimental isochromatics is demonstrated. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. ЦИКЛИЧЕСКАЯ ФАБУЛЬНАЯ МОДЕЛЬ В ГОТИЧЕСКОМ РАССКАЗЕ Х. УОЛПОЛА «МАЛЕНЬКОЕ ПРИВИДЕНИЕ»
- Author
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Бурцева, М.А.
- Subjects
готический рассказ ,фабула ,циклическая модель ,кумулятивная схема ,х. уолпол ,gothic story ,fabula ,cyclic model ,cumulative scheme ,h. walpole ,Philology. Linguistics ,P1-1091 - Abstract
В статье проводится анализ фабулы рассказа английского писателя Х. Уолпола «Маленькое привидение» в соответствии с циклической моделью сюжетосложения. Последовательно выделяются: отправка главного героя в графство Глебесшир после смерти близкого друга; пребывание в старинном доме семьи Болдуинов в поисках тишины и уединения; счастливое возвращение в Лондон, знаменующее восстановление исходной ситуации. Основной этап циклической схемы гипертрофируется в кумулятивный сюжет испытаний, ключевыми элементами которого становятся столкновения героя с холодным рационализмом хозяев, стихийным волюнтаризмом детей и контактом с существом из потустороннего мира. Редуцированная кумулятивная схема испытаний реализуется и пределах сюжетной линии призрака, совмещающейся с линией героя, что обусловливает идентичность художественного итога произведения в отношении этих персонажей. Аналитическое исследование рассказа Х. Уолпола на основании универсальной фабульной схемы позволяет, с одной стороны, рассматривать его в русле готической традиции, с другой - полнее раскрыть его художественное своеобразие.
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- 2021
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5. Study of Changes of the Individual Parameter of Resources in the Modelling of Renewable Systems
- Author
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Karelin, Oleksandr, Tarasenko, Anna, Barabash, Oleksandr, Gonzalez-Hernandez, Manuel, Medina-Marin, Joselito, Ao, Sio-Iong, editor, Gelman, Len, editor, and Kim, Haeng Kon, editor
- Published
- 2019
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6. Cyclic Model and Map for Estimating Predictive Potential of Prognostic-Planning Methodology Development
- Author
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Yu. I. Busheneva
- Subjects
methodology ,planning ,forecasting ,cyclic model ,predictive potential ,Political institutions and public administration (General) ,JF20-2112 - Abstract
The article states that in our country considerable experience has been gained in forecasting and planning work, the formation of which is based on certain methodological approaches that undergo transformation at different historical stages. The purpose of the article is to assess the features of the development of the forecasting and planning methodology of the domestic national economy in various historical periods of time.Based on the analysis of historical facts, the author’s expert assessment and graphic modeling techniques, a cyclic model and a map for assessing the predictive development potential of the forecasting and planning methodology of the domestic national economy are developed, which differs by identifying the stages in the development of forecasted and planned work depending on the nature of the obligatory execution, the depth of the impact of forecasts and plans for economic development, resource methods, predictability of the future.The results of the study can be applied in the activities of government to improve the quality of forecasting and planning work, to determine the turning points of phase shifts in the development of the forecasting and planning methodology.
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- 2021
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7. Effect of Size and Slenderness on the Axial-Compressive Behavior of Basalt FRP-Confined Predamaged Concrete.
- Author
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Ma, Gao, Chen, Xiaohuang, Biçici, Erkan, Hou, Chunxu, and Sezen, Halil
- Subjects
BASALT ,ULTIMATE strength ,CONCRETE ,ENGINEERING mathematics ,SIZE - Abstract
To investigate the size and slenderness effect on the axial-compressive behavior of basalt fiber–reinforced polymer (BFRP)-confined predamaged concrete, five groups of concrete cylinders with different sizes and slenderness ratios were designed and tested. The cylinders were axially preloaded to three predamage levels, then repaired using BFRP, and reloaded. The results showed that the concrete predamage had an adverse effect on the ultimate strength and initial elastic modulus of BFRP-confined concrete. Except for the smallest specimens affected by the wall effect, the initial analysis found that the ultimate strength of BFRP-confined concrete decreased with an increase in size and slenderness ratio, and the size and slenderness effect decreased with an increase in BFRP confining pressure, while these increased with the severity of concrete predamage. However, there was no obvious size or slenderness effect on the ultimate strain of BFRP-confined concrete. Through multifactorial analysis, it was confirmed that the ultimate strength of BFRP-confined undamaged and predamaged concrete was influenced by the slenderness. Considering the effect of size, slenderness, and predamage, monotonic and cyclic models were developed for BFRP-confined concrete. Finally, a uniaxial material object was added into OpenSees to provide an effective numerical material model for theoretical analyses and engineering applications. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
8. Time and Institutions
- Author
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Volchenkov, Dimitri, Abarbanel, Henry, Series editor, Braha, Dan, Series editor, Érdi, Péter, Series editor, Friston, Karl, Series editor, Haken, Hermann, Series editor, Jirsa, Viktor, Series editor, Kacprzyk, Janusz, Series editor, Kaneko, Kunihiko, Series editor, Kelso, Scott, Series editor, Kirkilionis, Markus, Series editor, Kurths, Jürgen, Series editor, Nowak, Andrzej, Series editor, Qudrat-Ullah, Hassan, Series editor, Schuster, Peter, Series editor, Schweitzer, Frank, Series editor, Sornette, Didier, Series editor, Thurner, Stefan, Series editor, and Volchenkov, Dimitri
- Published
- 2016
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9. Experimental study on four-point cyclic bending behaviours of concrete with high density polyethylene granules.
- Author
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Chen, Yuzhi, Xu, Lingyu, Xuan, Weihong, and Zhou, Zan
- Subjects
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CONCRETE , *HIGH density polyethylene , *BENDING (Metalwork) , *MATERIAL plasticity , *CYCLIC loads , *TENSILE tests - Abstract
Highlights • The impact of HDPE granule contents on tensile strength and deformation ability of concrete are studied. • Plastic strain and secant modulus of concrete with HDPE granules under cyclic tensile loading are investigated. • Unloading and reloading processes are characterized with both HDPE granule contents and damage. • A cyclic stress-strain model for concrete with different contents of HDPE granules is proposed. Abstract In recent years, plastic pollution has become more serious. The incorporation of waste plastic into concrete as part of the aggregate not only greatly reduces the environmental pressure, but also lowers the cost of concrete. In order to investigate the effect of plastic content on the mechanical properties of concrete, the MTS322 device was used to perform four-point bending monotonic and cyclic loading tests on concrete specimens with six contents of high density polyethylene (HDPE) granules. The test results show that with the increase of HDPE granule contents, both the tensile strength and the initial elastic modulus of concrete with HDPE granules declined gradually, while the peak strain increased. The plastic strain during the loading process was not affected by the HDPE granule content, but increased with the increase of unloading strain. According to the degradation of secant modulus during the cyclic loading process, the damage was defined, based on which the cyclic stress-strain model of concrete with HDPE granules was obtained. According to equations provided, the predicted model was in good agreement with the test results. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
10. Numerical simulation of soft brick unreinforced masonry walls subjected to lateral loads
- Author
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Jayaprakash Vemuri, Syed Ehteshamuddin, and Subramaniam Kolluru
- Subjects
soft brick masonry ,numerical analysis ,monotonic load envelope ,cyclic model ,hysteretic model ,simplified micro modeling ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Unreinforced soft-brick masonry structures comprise a large portion of buildings in earthquake prone regions of India. Recent earthquakes have extensively damaged such structures. Experimental and numerical studies on soft brick unreinforced masonry structures are scarce in literature. In this paper, numerical simulation of soft brick unreinforced masonry panels subjected to lateral loads is performed. At the panel level, the masonry structure is modelled using the micro modelling approach within a finite element framework. Monotonic load envelope curve is generated through a pushover analysis of the finite element model. The in-plane failure modes are identified, and the effect of aspect ratio and axial stress on failure is examined. Cyclic load analyses are performed on the finite element model to understand the complex hysteretic behaviour of unreinforced soft-brick masonry walls.
- Published
- 2018
- Full Text
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11. On Non-Singular Space-times and the Beginning of the Universe
- Author
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Craig, William Lane, Sinclair, James D., and Nagasawa, Yujin, editor
- Published
- 2012
- Full Text
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12. Cyclic stress-strain model incorporating buckling effect for steel reinforcing bars embedded in FRP-confined concrete.
- Author
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Bai, Yu-Lei, Dai, Jian-Guo, and Ozbakkaloglu, Togay
- Subjects
- *
REINFORCING bars , *MECHANICAL buckling , *STEEL , *REINFORCED concrete , *ENGINE cylinders - Abstract
Buckling of steel reinforcement usually causes a sudden loss of the load-carrying capacity and the ultimate state of conventional reinforced concrete (RC) cylinders. However, reinforcing bars behave differently in fiber-reinforced polymer (FRP)-confined RC cylinders due to the lateral confinement effect of FRP. This paper presents a theoretical study into the buckling behavior of longitudinal steel reinforcing bars embedded in FRP-confined concrete subjected to cyclic axial compression. An empirical monotonic compressive stress-strain model considering the buckling effects proposed previously for laterally supported reinforcing bars is extended to a cyclic model by combining the monotonic envelope and the Menegotto-Pinto model accounting for the cyclic loops. The cyclic stress-strain models for both laterally supported reinforcing bars and FRP-confined plain concrete are then implemented into the OpenSees software platform and validated through comparisons with compressive test results on cyclically loaded FRP-confined plain and RC cylinders. The proposed cyclic stress-strain model for laterally supported reinforcing bars is expected to serve as a fundamental model for predicting the seismic behavior of FRP-strengthened RC cylinders with widely-spaced transverse ties under cyclic axial compression, in which case the local buckling of reinforcing bars usually occurs between two adjacent transverse ties. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. ЦИКЛИЧЕСКАЯ ФАБУЛЬНАЯ МОДЕЛЬ В ГОТИЧЕСКОМ РАССКАЗЕ Х. УОЛПОЛА «МАЛЕНЬКОЕ ПРИВИДЕНИЕ»
- Subjects
х. уолпол ,gothic story ,фабула ,циклическая модель ,кумулятивная схема ,готический рассказ ,fabula ,P1-1091 ,cumulative scheme ,h. walpole ,cyclic model ,Philology. Linguistics - Abstract
В статье проводится анализ фабулы рассказа английского писателя Х. Уолпола «Маленькое привидение» в соответствии с циклической моделью сюжетосложения. Последовательно выделяются: отправка главного героя в графство Глебесшир после смерти близкого друга; пребывание в старинном доме семьи Болдуинов в поисках тишины и уединения; счастливое возвращение в Лондон, знаменующее восстановление исходной ситуации. Основной этап циклической схемы гипертрофируется в кумулятивный сюжет испытаний, ключевыми элементами которого становятся столкновения героя с холодным рационализмом хозяев, стихийным волюнтаризмом детей и контактом с существом из потустороннего мира. Редуцированная кумулятивная схема испытаний реализуется и пределах сюжетной линии призрака, совмещающейся с линией героя, что обусловливает идентичность художественного итога произведения в отношении этих персонажей. Аналитическое исследование рассказа Х. Уолпола на основании универсальной фабульной схемы позволяет, с одной стороны, рассматривать его в русле готической традиции, с другой - полнее раскрыть его художественное своеобразие., The article analyzes the fabula of the story “The Little Ghost” by an English writer Hugh Walpole following the cyclical model of plot construction. The sequence of events is as follows: the main character setting off to the County of Glebesshire after the death of a close friend; his stay at the old house of the Baldwin family in search of peace and solitude; his happy return to London, marking the restoration of the original situation. The main stage of the cyclic scheme is hypertrophied into a cumulative plot of tests, the key elements of which being the hero's encounters with the cold rationalism of the owners and the spontaneous voluntarism of the children, as well as a contact with a creature from the other world. The reduced cumulative test scheme is also implemented within the ghost storyline, combined with the hero's line, which determines the identical artistic outcomes in relation to these characters of the story. Based on the universal fabula scheme, an analytical study of H. Walpole's story allows, on the one hand, to consider it in the context of the Gothic tradition and on the other hand – to reveal its artistic originality in full., Russian Linguistic Bulletin, Выпуск 2 (26) 2021, Pages 129-135
- Published
- 2021
14. Stationary and Non-Stationary Models of Extreme Ground-Level Ozone in Peninsular Malaysia
- Author
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Nasrul Hamidin, Noor Fadhilah Ahmad Radi, Siti Aisyah Zakaria, and Nor Azrita Mohd Amin
- Subjects
Statistics and Probability ,Cyclic model ,Economics and Econometrics ,Location parameter ,Ground Level Ozone ,Likelihood-ratio test ,Statistics ,Generalized extreme value distribution ,Linear model ,Statistics, Probability and Uncertainty ,Akaike information criterion ,Air quality index ,Mathematics - Abstract
High ground-level ozone (GLO) concentrations will adversely affect human health, vegetations as well as the ecosystem. Therefore, continuous monitoring for GLO trends is a good practice to address issues related to air quality based on high concentrations of GLO. The purpose of this study is to introduce stationary and non-stationary model of extreme GLO. The method is applied to 25 selected stations in Peninsular Malaysia. The maximum daily GLO concentration data over 8 hours from year 2000 to 2016 are used. The factors of this distribution are anticipated using maximum likelihood estimation. A comparison between stationary (constant model) and non-stationary (linear and cyclic model) is performed using the likelihood ratio test (LRT). The LRT is based on the larger value of deviance statistics compared to a chi-square distribution providing the significance evidence to non-stationary model either there is linear trend or cyclic trend. The best fit model between selected models is tested by Akaike's Information Criterion. The results show that 25 stations conform to the non-stationary model either linear or cyclic model, with 14 stations showing significant improvement over the linear model in location parameter while 11 stations follow the cyclic model. This study is important to identify the trends of ozone phenomenon for better quality risk management.
- Published
- 2021
15. COMMUNICATIVE COMPETENCE OF BACHELORS OF EDUCATION IN THE FIELD OF HEALTH AND SAFETY: CONCEPTUAL APPROACHES AND CYCLIC MODEL OF FORMATION
- Author
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G. S. Kamerilova and M. A. Kartavykh
- Subjects
communicative competence ,bachelor of education ,health and safety ,world outlook ideas ,cyclic model ,phase logic of formation of communicative competence ,dialogue ,Education (General) ,L7-991 - Abstract
In article the role of communicative competence of training of bachelors of education in the field of health and safety reveals, are proved an image communicatively - the competent teacher ready and capable to the diverse intersubject dialogue providing the general vision of sharpness of problems of safe activity as bases for development of uniform decisions and actions. The methodology of formation of communicative competence at bachelors of education in the field of health and safety including the leading world outlook ideas, psychology and pedagogical approaches, the methodical principles is considered. The cyclic model of formation of communicative competence of bachelors of education on the basis of the maintenance of the educational area "Health and safety" including target, substantial, procedural, technological, reflexive and estimated components is proved. Cyclic process of formation of communicative competence at bachelors has phase logic and is based on various models of communication and the corresponding smyslotselevy dialogues. Assessment of effectiveness was determined by levels of formation of communicative competence and showed positive dynamics.
- Published
- 2017
16. Modelo dinámico para analizar el ciclo de construcción de vivienda económica de la zona metropolitana de San Luis Potosí, México
- Author
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Parra Rodríguez, Omar, López Mares, Lourdes Marcela, Pérez Pozos, Omar Nahúm, and Alva Fuentes, Benjamín
- Subjects
políticas públicas ,public policy ,planeación urbana ,housing offer and demand ,disponibilidad del suelo ,precio de la tierra ,modelo cíclico ,oferta y demanda de vivienda ,land price ,cyclic model ,land availability ,urban planning - Abstract
Housing is one of the most dynamic markets in cities. However, low-income housing in Mexico, whose acquisition is subsidized by the public sector, does not behave the same and is in constant deficit. The objective of this research is to identify and project into the future the most important variables that intervene in the construction cycle of this type of housing in the Metropolitan Area of San Luis Potosí, Mexico. This is a prospective study that estimates possible future scenarios with specialized simulation software. The study variables were identified from the literature review and interviews with experts. Subsequently, these were projected for 20 years using a dynamic cyclical structure model. The results of the study show that the variable of greatest interference is the price per square meter of land, which rises in relation to its availability and increases the housing price. If this variable maintains its increasing trend, building affordable housing in the study area will not be feasible in the next five years. If, on the other hand, the availability of land is increased by 35%, the trend in the price of land will decrease by 10% and that of housing by 5%, increasing its affordability. This situation demands public policies that promote access to affordable land for the construction of inexpensive housing for underprivileged strata of the population., La vivienda es uno de los mercados más dinámicos en las ciudades. Sin embargo, la vivienda de interés social en México, cuya producción y adquisición es subsidiada por el sector público no se comporta igual y presenta déficits constantes. Esta investigación tiene por objetivo el identificar y proyectar a futuro las variables de mayor injerencia en el ciclo de construcción de este tipo de vivienda en la Zona Metropolitana de San Luis Potosí, México. Este es un estudio prospectivo en el que se utilizó software especializado de simulación para estimar posibles escenarios futuros. Las variables de estudio fueron identificadas a partir de la revisión literaria y de entrevistas con expertos en el tema. Posteriormente, estas fueron proyectadas a 20 años mediante un modelo dinámico de estructura cíclica. Los resultados del estudio muestran que la variable de mayor injerencia es el precio por metro cuadrado de terreno, que se eleva en relación a su disponibilidad y a la vez incrementa el precio de la vivienda. Si esta variable mantiene su tendencia incremental, construir vivienda de interés social en el área de estudio no será factible en los próximos cinco años. Si, por el contrario, se incrementa la disponibilidad del suelo en un 35%, la tendencia del precio de la tierra decrecería un 10% y el de la vivienda un 5%, incrementando su asequibilidad. Esta situación demanda políticas públicas que promuevan el acceso al suelo asequible para la construcción de vivienda económica para estratos desfavorecidos de la población.
- Published
- 2022
- Full Text
- View/download PDF
17. An enhanced damage plasticity model for predicting the cyclic behavior of plain concrete under multiaxial loading conditions
- Author
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Ertugrul Taciroglu and Mohammad Reza Azadi Kakavand
- Subjects
Cyclic model ,021110 strategic, defence & security studies ,Materials science ,Tension (physics) ,business.industry ,Constitutive equation ,0211 other engineering and technologies ,Uniaxial tension ,020101 civil engineering ,02 engineering and technology ,Structural engineering ,Plasticity ,Compression (physics) ,0201 civil engineering ,Architecture ,Ultimate tensile strength ,business ,Independence (probability theory) ,Civil and Structural Engineering - Abstract
Some of the current concrete damage plasticity models in the literature employ a single damage variable for both the tension and compression regimes, while a few more advanced models employ two damage variables. Models with a single variable have an inherent difficulty in accounting for the damage accrued due to tensile and compressive actions in appropriately different manners, and their mutual dependencies. In the current models that adopt two damage variables, the independence of these damage variables during cyclic loading results in the failure to capture the effects of tensile damage on the compressive behavior of concrete and vice-versa. This study presents a cyclic model established by extending an existing monotonic constitutive model. The model describes the cyclic behavior of concrete under multiaxial loading conditions and considers the influence of tensile/compressive damage on the compressive/tensile response. The proposed model, dubbed the enhanced concrete damage plasticity model (ECDPM), is an extension of an existing model that combines the theories of classical plasticity and continuum damage mechanics. Unlike most prior studies on models in the same category, the performance of the proposed ECDPM is evaluated using experimental data on concrete specimens at the material level obtained under cyclic multiaxial loading conditions including uniaxial tension and confined compression. The performance of the model is observed to be satisfactory. Furthermore, the superiority of ECDPM over three previously proposed constitutive models is demonstrated through comparisons with the results of a uniaxial tension-compression test and a virtual test.
- Published
- 2020
18. РЕФЛЕКСИЯТА В ОБУЧЕНИЕТО ПО „ИНФОРМАЦИО...
- Author
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Тодорова, Елена and Чиликова, Стелиана
- Abstract
The article explores the formation of reflexive skills of students in the process of studying the topic “Computer Text Editing” at school. This study provides a detailed explanation of the applications of the ALACT model where the process of reflection is realized via a cyclic model. An overlook on specific examples from the IT education which realize reflection is given. [ABSTRACT FROM AUTHOR]
- Published
- 2016
19. Cyclic performance of composite shear walls with boundary elements
- Author
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Siamak Epackachi, Nakisa Haghi, and Mohammad Kazemi
- Subjects
Cyclic model ,Materials science ,business.industry ,Composite number ,0211 other engineering and technologies ,Stiffness ,Boundary (topology) ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Structural engineering ,Finite element method ,0201 civil engineering ,Composite plate ,021105 building & construction ,Architecture ,medicine ,Shear strength ,Shear wall ,medicine.symptom ,Safety, Risk, Reliability and Quality ,business ,Civil and Structural Engineering - Abstract
In the past three decades, several experiments were conducted to investigate the seismic behavior of composite plate shear walls (C-PSW) because of their advantages to conventional reinforced concrete (RC) and steel plate shear walls (SPSW). Numerical studies, however, are limited due to the complexities for the finite element modeling of the steel and concrete material behaviors and their composite action. Herein, the cyclic behavior of various C-PSW with and without boundary elements (BE) is investigated numerically. The effects of design parameters such as aspect ratio, axial load ratio, and the length of the BE on the response of C-PSW are investigated. The advanced finite element software LS-DYNA is utilized to develop the cyclic model of C-PSW. The LS-DYNA model is validated using the available experimental data in the literature. Numerical analyses indicate that the BE has a significant impact on the stiffness, strength, and energy absorption of C-PSW especially in high aspect ratio walls. A simplified method is proposed to estimate the peak shear strength of C-PSW with BE using the results of the numerical and experimental study.
- Published
- 2020
20. The cyclic model of use diffusion-adoption on the decision to select mobile network operator
- Author
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Widya Granita, Ngadino Surip, Yuli Harwani, and Rina Astini
- Subjects
Cyclic model ,user evaluation ,Mathematical optimization ,business.industry ,Computer science ,media_common.quotation_subject ,lcsh:HF5735-5746 ,task technology fit ,lcsh:Business records management ,General Business, Management and Accounting ,usage behavior ,Loyalty ,needs technology fit ,Diffusion (business) ,business ,cyclic ,Versa ,Mobile network operator ,media_common - Abstract
During the last few years, the growth of mobile data service users has increased, followed by stagnant usage and even tends to decline. The challenge that mobile telecommunications operators face is increasing revenue in a situation of intense competition in the mature telecommunications industry market. It takes customers systematically, through ordering, behavior based on the suitability of technology that functions to meet user’s needs. Thus, Mobile Network Operator (MNO) provides user satisfaction scores, thereby increasing use and loyalty to the MNO it has chosen. This study aims to cyclically analyze the decision to choose an operator in shaping evaluation use behavior to create loyalty and continued use. In this study, quantitative data was carried out through a survey of 250 respondents and data analysis using Structural Equation Modelling (SEM). The findings in this study are: (1) The decision to choose MNO affects usage behavior and vice versa (2) The decision to choose MNO influences user evaluation and vice versa; (3) Usage behavior influences user evaluation. The results of this study can enrich the literature with theoretical contributions related to the concept of behavior in organizations, especially the telecommunications industry. Besides, it can assist mobile operators in designing usage behavior.
- Published
- 2020
21. Spatial and temporal landscape patterns in arid and semi-arid African savannas
- Author
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Belsky, A. Joy, Hansson, Lennart, editor, Fahrig, Lenore, editor, and Merriam, Gray, editor
- Published
- 1995
- Full Text
- View/download PDF
22. Theoretical investigation of the excited states dynamics of the polydiacetylene backbone
- Author
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Barisien, T., Turki, M., Daniel, C., Bigot, J.-Y., Schäfer, F. P., editor, Toennies, J. P., editor, Zinth, W., editor, Elsaesser, T., Mukamel, S., Murnane, M. M., and Scherer, N. F.
- Published
- 2001
- Full Text
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23. By Way of Introduction: Alliances Between Science Research and Innovation Research
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Grupp, Hariolf, Albrecht, Edo, Koschatzky, Knut, and Grupp, Hariolf, editor
- Published
- 1992
- Full Text
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24. Experimental Study on Waste Tire Chips-Reinforced Sand Using Cyclic Plate Load Test
- Author
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Ashirbad Satapathy, Sanket Rawat, and Ravi Kant Mittal
- Subjects
Cyclic model ,Mixing (process engineering) ,Environmental science ,Geotechnical engineering ,Bearing capacity ,Reinforcement ,Compression (physics) ,Subsoil ,Plate load test ,Intensity (heat transfer) - Abstract
The scarcity in availability of suitable land and the associated huge costs for construction of deep and large foundations supporting tall superstructures have compelled engineers across the globe to resort to numerous ground improvement techniques to improve the subsoil properties. With the emphasis on sustainable construction practices and waste management techniques gaining attention worldwide, research towards the same to alleviate engineering problems has witnessed a surge. Therefore, the use of industrial, common and construction wastes for enhancement of structural properties in fresh construction is being studied widely. Similarly, utilizing shredded waste tire chips as reinforcement in soil has shown promising results. In the present study, cyclic model footing load tests are performed on square footing supported by a sand bed reinforced with randomly distributed waste tire chips in a square tank. Various intensities of cyclic loads (loading, unloading, and reloading) are applied on the model footing and subsequently, the elastic rebound of the footing corresponding to each intensity of loading and the pattern of variation of the coefficient of elastic uniform compression (Cu) of reinforced sand are assessed. The influence of different percentages of tire chips (5–40%) is analyzed by randomly mixing them in the soil medium at 70% equivalent relative density for a depth of up to the width of the footing. The results indicate that tire chip addition can significantly improve the bearing capacity as well as the coefficient of elastic uniform compression and this improvement can further be enhanced on an increase in the percentage of reinforcement (improvement of up to 50% is observed).
- Published
- 2021
25. Seismic evaluation of reinforced concrete structures infilled with masonry infill walls
- Author
-
Mohamed Sayed Gomma, Hany El-Ghazaly, and Mohamed Magdi Abdelaziz
- Subjects
Soft story building ,Cyclic model ,Infilled frames ,business.industry ,Seismic loading ,Infill ,Structural engineering ,Masonry ,Reinforced concrete ,business ,Software package ,Geology ,Civil and Structural Engineering - Abstract
The current research work aims to investigate the seismic performance of the reinforced concrete structures fully, as well as, partially infilled with masonry infill (MI) walls. For that, a numerical study of three groups of two-dimensional framed structure has been conducted under dynamic time–history analysis. The three building groups are classified as nine, six and three stories representing high-rise building, medium-rise building, and low-rise building, respectively. Different infill walls’ configurations have been studied for each group to simulate the bare frame, the infilled frame, the open ground story frame, and the partially opened ground story frame. Double-strut nonlinear cyclic model for MI walls has been utilized to represent nonlinear behavior of infill walls in the framed structures using the structural software package SeismoStruct software. Dynamic time–history analysis, using three different ground motion records to represent wide range of frequency content, has been utilized to study the performance of the studied cases under seismic loading conditions. Based on the obtained results, the seismic performance of the framed structures is strongly influenced after using the infill walls. However, removing the MI walls from the ground story leads to soft story phenomena and makes the structures vulnerable to collapse especially in moderate-to-severe earthquakes.
- Published
- 2019
26. Prediction of oedometer terminal densities through a memory-enhanced cyclic model for sand
- Author
-
Federico Pisanò and H. Y. Liu
- Subjects
Cyclic model ,Plasticity ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,Oedometer test ,0201 civil engineering ,Terminal (electronics) ,Numerical modelling ,Earth and Planetary Sciences (miscellaneous) ,Geotechnical engineering ,Cyclic response ,Constitutive relations ,Geology ,021101 geological & geomatics engineering - Abstract
Predicting the cyclic response of soils is still challenging in many geotechnical applications. In this area, the continual efforts on the constitutive modelling of cyclic sand behaviour demand new and reliable dataset for model validation – even more so for loading conditions involving numerous loading cycles (‘high-cyclic’ loading). This paper concerns the recent memory-enhanced bounding surface formulation by Liu et al. as a suitable platform to reproduce the high-cyclic response of sands. New evidence of its suitability is provided based on the recent dataset published by Park and Santamarina, comprising the results of high-cyclic oedometer tests at varying initial/loading conditions. Model simulations show satisfactory agreement with experimental data, and prove the ability of the model to predict ‘terminal densities’ under confined cyclic compression.
- Published
- 2019
27. Stress-strain model for FRP-confined concrete subject to arbitrary load path
- Author
-
Feng Xing, Pengda Li, Yu-Fei Wu, and Yingwu Zhou
- Subjects
Cyclic model ,Materials science ,business.industry ,Mechanical Engineering ,Stress–strain curve ,Tangent ,Modulus ,02 engineering and technology ,Structural engineering ,Fibre-reinforced plastic ,Plasticity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Stress (mechanics) ,Mechanics of Materials ,Ceramics and Composites ,Cylinder stress ,Composite material ,0210 nano-technology ,business - Abstract
Most existing stress-strain models for fiber reinforced polymer (FRP) confined concrete are applicable to monotonic loading or complete cyclic loading where unloading/reloading is a continuous process between envelope curve and zero stress. However, load cycling is mostly incomplete or partial in practical problems where reverse of loading occurs before the previous load cycle is completed, and this unloading and reloading process is random. Cyclic model allowing for random partial load cycling is rare, if any, due to the lack of experimental data, and the insufficient understanding on the behavior of confined concrete under partial cyclic loading. In this study, FRP confined concrete cylinders were tested under six typical cyclic load patterns. The test results reveal that the partial cyclic stress-strain behavior is different from that under full cyclic loading. The key parameters determining unloading/reloading curves, such as reloading modulus, plastic strain, and tangent unloading modulus are related to loading history and axial stress level. It is found that the key parameters will change, or accumulative damage to concrete will occur, only under certain condition which is defined as effective partial cyclic loading in this work. A simple method is proposed to define the effective partial cyclic loading. Based on an existing complete cyclic model, a stress-strain model for FRP confined concrete under random partial cyclic loading is developed in this work. The proposed model performs well under different load patterns.
- Published
- 2019
28. Long term cyclic behavior of unsaturated granular soils
- Author
-
Zhigang Cao, Jingyu Chen, Eduardo Alonso, Chuan Gu, and Yuanqiang Cai
- Subjects
Cyclic model ,Cyclic stress ,Materials science ,Suction ,0211 other engineering and technologies ,Transportation ,02 engineering and technology ,Geotechnical Engineering and Engineering Geology ,Granular material ,Subbase (pavement) ,Long period ,021105 building & construction ,Soil water ,Geotechnical engineering ,Deformation (engineering) ,021101 geological & geomatics engineering ,Civil and Structural Engineering - Abstract
The road base and subbase materials are normally situated in unsaturated conditions, and are subject to traffic loadings over a long period of time. To study the influences of matric suction on the long-term deformation of road base and subbase materials, the large-scale cyclic tri-axial apparatus, equipped with unsaturated system, was adopted to conduct tests on these unsaturated coarse granular materials. Four matric suction and three cyclic stress amplitudes were applied on the specimens through the apparatus. The axis-translation technique was used to control the matric suction in the specimen. The test results indicate that with the increase of matric suction, the axial accumulated strain decreases at the declining rate, and larger cyclic stress amplitude will strengthen the influence of matric suction. An improved cyclic model containing a new exponential function to describe the influence of matric suction was then proposed. By comparing the experimental results and the calculated results, the improved model was validated to be effective to predict the long-term deformation of unsaturated granular soils.
- Published
- 2018
29. Fractional-Order Elastoplastic Modeling of Sands Considering Cyclic Mobility
- Author
-
Wei Cheng, Leiye Wu, and Zhehao Zhu
- Subjects
liquefaction ,Constitutive equation ,0211 other engineering and technologies ,020101 civil engineering ,Ocean Engineering ,constitutive model ,02 engineering and technology ,Plasticity ,0201 civil engineering ,soil ,Stress (mechanics) ,lcsh:Oceanography ,lcsh:VM1-989 ,Geotechnical engineering ,lcsh:GC1-1581 ,Seabed ,021101 geological & geomatics engineering ,Water Science and Technology ,Civil and Structural Engineering ,Cyclic model ,Liquefaction ,lcsh:Naval architecture. Shipbuilding. Marine engineering ,fractional order ,cyclic mobility ,Submarine pipeline ,Reduction (mathematics) ,Geology - Abstract
Seabed soil may experience a reduction in strength or even liquefaction when subjected to cyclic loadings exerted by offshore structures and environmental loadings such as ocean waves and earthquakes. A reasonable and robust constitutive soil model is indispensable for accurate assessment of such structure–seabed interactions in marine environments. In this paper, a new constitutive model is proposed by enriching subloading surface theory with a fractional-order plastic flow rule and multiple hardening rules. A detailed validation of both stress- and strain-controlled undrained cyclic test results of medium-dense Karlsruhe fine sand is provided to demonstrate the robustness of the present constitutive model to capture the non-associativity and cyclic mobility of sandy soils. The new fractional cyclic model is then implemented into a finite element code based on a two-phase field theory via a user subroutine, and a numerical case study on the response of seabed soils around a submarine pipeline under cyclic wave loadings is presented to highlight the practical applications of this model in structure–seabed interactions.
- Published
- 2021
30. Model of Soft Soils under Cyclic Loading.
- Author
-
Jing Ni, Indraratna, Buddhima, Xue-Yu Geng, Carter, John Phillip, and You-Liang Chen
- Subjects
- *
REGOLITH , *CRUST of the earth , *ARABLE land , *PLANT growing media , *CYCLIC loads , *MECHANICAL loads - Abstract
This paper presents a new constitutive model for cyclic loading of soil to predict the behavior of soft clays under undrained cyclic triaxial loading. It is inspired by the modified Cam-clay theory, and a new yield surface for elastic unloading is proposed to capture the soil behavior under cyclic loading. Only two additional parameters that characterize the cyclic behavior are used together with the traditional parameters associated with the modified Cam-clay constitutive model. The details of the relevant soil properties, initial states, and cyclic loading conditions are presented, and a computational procedure for determining the effective stresses and strains is demonstrated. The new model is used to simulate cyclic triaxial tests on kaolin, and the model predictions are generally found to be in agreement with the measured excess pore pressures and axial strains. Furthermore, numerous factors that influence the cyclic performance of soft soils can be considered in the new model, such as cyclic stress ratios, preshearing, and cyclic loading frequency. The critical cyclic stress ratio is also predictable using the proposed model in terms of excess pore pressures and axial strains. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
31. Seismic Evaluation and Retrofit of Reinforced Concrete Buildings with Masonry Infills Based on Material Strain Limit Approach
- Author
-
Denise-Penelope N. Kontoni, Mangeshkumar R. Shendkar, P. R. Maiti, Omid Tavasoli, and S. Mandal
- Subjects
Article Subject ,QC1-999 ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,0201 civil engineering ,021105 building & construction ,Infill ,medicine ,Reduction factor ,Civil and Structural Engineering ,Cyclic model ,business.industry ,Mechanical Engineering ,Physics ,Design tool ,Stiffness ,Structural engineering ,Strain limit ,Masonry ,Geotechnical Engineering and Engineering Geology ,Condensed Matter Physics ,Reinforced concrete ,Mechanics of Materials ,medicine.symptom ,business ,Geology - Abstract
The seismic evaluation and retrofit of reinforced concrete (RC) structures considering masonry infills is the correct methodology because the infill walls are an essential part of RC structures and increase the stiffness and strength of structures in seismically active areas. A three-dimensional four-storey building with masonry infills has been analyzed with nonlinear static adaptive pushover analysis by using the SeismoStruct software. Two models have been considered in this study: the first model is a full RC-infilled frame and the second model is an open ground storey RC-infilled frame. The infill walls have been modeled as a double strut nonlinear cyclic model. In this study, the “material strain limit approach” is first time used for the seismic evaluation of RC buildings with masonry infills. This method is based on the threshold strain limit of concrete and steel to identify the actual damage scenarios of the structural members of RC structures. The two models of the four-storey RC building have been retrofitted with local and global strengthening techniques (RC-jacketing method and incorporation of infills) as per the requirements of the structure to evaluate their effect on the response reduction factor (R) because the R-factor is an important design tool that shows the level of inelasticity in a structure. A significant increase in the response reduction factor (R) and structural plan density (SPD) has been observed in the case of the open ground storey RC-infilled frame after the retrofit. Thus, this paper aims to present a most effective way for the seismic evaluation and retrofit of any reinforced concrete structure through the material strain limit approach.
- Published
- 2021
- Full Text
- View/download PDF
32. On Optimal Leader’s Investments Strategy in a Cyclic Model of Innovation Race with Random Inventions Times
- Author
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Sergey Mironovich Aseev and Masakazu Katsumoto
- Subjects
Statistics and Probability ,R& ,Computer science ,media_common.quotation_subject ,O40 ,Time horizon ,lcsh:Technology ,optimal allocation of resources ,imitation ,lcsh:Social Sciences ,0502 economics and business ,ddc:330 ,dynamic optimization ,050207 economics ,media_common ,Cyclic model ,technology spillovers ,R&D ,lcsh:T ,Stochastic process ,Technological change ,Applied Mathematics ,05 social sciences ,O30 ,Probabilistic logic ,lcsh:H ,C61 ,stochastic innovation race ,Product (mathematics) ,050211 marketing ,Stochastic optimization ,Statistics, Probability and Uncertainty ,Imitation ,Mathematical economics ,amp - Abstract
In this paper, we develop a new dynamic model of optimal investments in R&, D and manufacturing for a technological leader competing with a large number of identical followers on the market of a technological product. The model is formulated in the form of the infinite time horizon stochastic optimization problem. The evolution of new generations of the product is treated as a Poisson-type cyclic stochastic process. The technology spillovers effect acts as a driving force of technological change. We show that the original probabilistic problem that the leader is faced with can be reduced to a deterministic one. This result makes it possible to perform analytical studies and numerical calculations. Numerical simulations and economic interpretations are presented as well.
- Published
- 2020
33. Notes on the post-bounce background dynamics in bouncing cosmologies
- Author
-
Ui Ri Mun, Thae Hyok Kim, Ok Song An, and Jin U Kang
- Subjects
Cyclic model ,Physics ,High Energy Physics - Theory ,Nuclear and High Energy Physics ,Spacetime Singularities ,COSMIC cancer database ,Computer Science::Information Retrieval ,Dynamics (mechanics) ,FOS: Physical sciences ,QC770-798 ,General Relativity and Quantum Cosmology (gr-qc) ,Cosmology of Theories beyond the SM ,Negative exponential ,General Relativity and Quantum Cosmology ,Ekpyrotic universe ,High Energy Physics - Theory (hep-th) ,Nuclear and particle physics. Atomic energy. Radioactivity ,Statistical physics ,Scalar field - Abstract
We investigate the post-bounce background dynamics in a certain class of single bounce scenarios studied in the literature, in which the cosmic bounce is driven by a scalar field with negative exponential potential such as the ekpyrotic potential. We show that those models can actually lead to cyclic evolutions with repeated bounces. These cyclic evolutions, however, do not account for the currently observed late-time accelerated expansion and hence are not cosmologically viable. In this respect we consider a new kind of cyclic model proposed recently and derive some cosmological constraints on this model., 26 pages, 15 figures. Significantly revised and accepted version for JHEP
- Published
- 2020
34. RC frame structures retrofitted by FRP-wrapping: A model for columns under axial loading and cyclic bending
- Author
-
Marco Savoia, Maria Zucconi, Barbara Ferracuti, Ferracuti B., Savoia M., and Zucconi M.
- Subjects
Cyclic model ,Cyclic constitutive law ,Distributed plasticity ,Materials science ,business.industry ,0211 other engineering and technologies ,RC column ,020101 civil engineering ,02 engineering and technology ,Structural engineering ,Bending ,Plasticity ,Fibre-reinforced plastic ,FRP – wrapping ,Finite element method ,0201 civil engineering ,021105 building & construction ,Retrofitting ,Axial force and cyclic bending ,Pushover analysi ,Seismic risk ,business ,Ductility ,Civil and Structural Engineering ,Confinement - Abstract
In order to mitigate the seismic risk of existing RC frame structures not designed with seismic criteria, a widespread strengthening strategy is based on increasing strength and ductility of RC columns by means of Fiber Reinforced Polymer wrapping. The existing models for RC cross-sections wrapped by FRP sheets were developed principally considering pure axial loads with uniform confinement pressure. In seismic areas, RC columns are instead usually subjected to axial load and cyclic bending. In the present work, in order to consider the effective loading conditions, an iterative cyclic model for square RC cross-sections wrapped by composite FRP sheets subjected to axial force and cyclic bending is proposed. The model considers the strain gradient-effect over the cross-section due to the bending loads that change significantly the confinement level of RC cross-section. Moreover, the model has been validated by comparing the numerical outcomes with various cyclic experimental results. The model has been also implemented in an open-source software with distributed plasticity finite elements in order to perform pushover analyses of an existing RC frame structure with different retrofitting strategies to improve the ductility of the columns for lateral forces.
- Published
- 2020
35. ЦИКЛИЧНАЯ МОДЕЛЬ СМЕШАННОГО ОБУЧЕНИЯ: ТЕХНОЛОГИЧЕСКИЙ ПОДХОД
- Subjects
BLENDED LEARNING ,ЭЛЕКТРОННЫЕ СРЕДСТВА ОБУЧЕНИЯ ,ELECTRONIC TOOLS ,ОНЛАЙН ОБУЧЕНИЕ ,ONLINE LEARNING ,CYCLIC MODEL ,ПЕРЕВЕРНУТЫЙ КЛАСС ,СМЕШАННОЕ ОБУЧЕНИЕ ,ЦИКЛИЧНАЯ МОДЕЛЬ ,FLIPPED CLASSROOM - Abstract
Актуальность исследуемой проблемы обусловлена необходимостью преодолеть разрыв между стремительным ростом индустрии электронных средств обучения и недостаточным дидактическим обоснованием их использования в процессе обучения. Цель данной статьи выявить параметры для построения технологической модели смешанного обучения для организации учебной деятельности обучающихся с использованием электронных средств обучения. В исследовании применен общенаучный системный подход, в соответствии с которым обучение рассматривается как сложная динамическая многоуровневая система, а также дидактический подход технологического проектирования и моделирования образовательных систем. Анализ зарубежной и отечественной литературы показал, что существующие технологические модели смешанного обучения основаны на соотношении онлайн-обучения дома и «лицом к лицу» в классе, причем параметры моделей жестко привязаны друг к другу, что ограничивает дидактические возможности применения таких моделей. На основе анализа сущностных характеристик смешанного обучения предложена цикличная модель смешанного обучения, разработанная в русле технологического подхода. Цикличная модель состоит из трех компонентов: 1. Целевой компонент: (1) ознакомление с материалом; (2) его отработка; (3) контроль сформированности знаний, умений и навыков. 2. Средства обучения (электронные или не электронные. 3. Место обучения (в учебном заведении или вне его). Три составляющие целевого компонента отражают логику учебного процесса и образуют один цикл. Циклы следуют друг за другом непрерывно по восходящей спирали. Две составляющие из второго и третьего компонентов цикличной модели могут комбинироваться между собой в любых сочетаниях и свободно применяться на любом из трех этапов цикла. Модели присущи такие характеристики, как целенаправленность, последовательность, вариативность и гибкость. На ее основе можно построить разнообразные варианты обучения для учебной группы в целом, сочетая компоненты в зависимости от конкретной дидактической задачи, состава группы, обеспеченности образовательного учреждения электронными средствами и других условий обучения. Кроме того, цикличная модель может служить инструментом для построения индивидуальных образовательных маршрутов отдельных обучающихся. Модель носит общепедагогический характер и может быть применена в преподавании любой дисциплины.
- Published
- 2020
- Full Text
- View/download PDF
36. Application of a high-cycle accumulation model to the analysis of soil liquefaction around a vibrating pile toe.
- Author
-
Osinov, V. A.
- Subjects
- *
BIOACCUMULATION , *SOIL liquefaction , *SOIL mechanics , *HIGH technology industries personnel , *ATMOSPHERIC pressure , *SOIL physics - Abstract
High residual pore pressure observed in the vicinity of piles driven in saturated soil indicates that the soil around the pile may be liquefied. In the present paper, the problem of deformation of saturated sand around a vibrating pile is formulated with the use of a high-cycle accumulation model capable of describing a large number of cycles. The problem is solved numerically for locally undrained conditions in spherically symmetric formulation suitable for the lower part of a cylindrical closed-ended pile near the toe. The aim of the study is to calculate the evolution of the liquefaction zone around the pile for a large number of cycles. A parametric study is carried out to show how the growth of the liquefaction zone depends on the pile displacement amplitude, the relative soil density, the effective stress in the far field and the pore fluid compressibility. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
37. Simplified plasticity damage model for large rupture strain (LRS) FRP-confined concrete
- Author
-
Qiang Han, Yu-Lei Bai, Yu-Feng Zhang, Shi-Jie Mei, Jian-Guo Dai, and Junfeng Jia
- Subjects
Cyclic model ,Materials science ,Strain (chemistry) ,business.industry ,Structural engineering ,Plasticity ,Fibre-reinforced plastic ,Rc columns ,Structural load ,Ceramics and Composites ,Axial load ,business ,Softening ,Civil and Structural Engineering - Abstract
Large rupture strain (LRS) fiber-reinforced polymers (FRP) composites with an elongation greater than 5% offer an attractive solution for seismic strengthening of reinforced concrete (RC) columns. For a quick and reliable design of LRS FRP-strengthened RC columns, this paper presents a simplified plasticity damage model for LRS FRP-confined concrete under cyclic axial compression. This model consists of two parts: (a) a recent monotonic LRS FRP-confined concrete model developed by the authors’ group as an envelope curve and (b) a simplified linear plasticity damage cyclic rule for predicting unloading and reloading paths. To solve the cyclic model deviation induced by concrete softening under a large axial strain, a pseudo-plastic strain was proposed, based on which the damage degradation of FRP-confined concrete can be quantified. The model comparisons show that although the proposed model sacrificed some precision when directly applied for the cyclic axial compressive behavior of FRP-confined concrete, it can give similarly accurate predictions as a complex model does for the behavior of conventional or LRS FRP-jacketed RC columns under a combined axial load and cyclic lateral load. Thus, this simplified plasticity damage model serves as a promising basic model for simulation of the seismic performance of FRP-strengthened structures.
- Published
- 2022
38. Cyclic stress-strain model for FRP-confined concrete considering post-peak softening
- Author
-
Pengda Li, Yingwu Zhou, Yu-Fei Wu, and Feng Xing
- Subjects
Cyclic model ,Cyclic stress ,Materials science ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,Strain hardening exponent ,Fibre-reinforced plastic ,0201 civil engineering ,Strain softening ,Condensed Matter::Materials Science ,021105 building & construction ,Ceramics and Composites ,Hardening (metallurgy) ,Cyclic loading ,Composite material ,Softening ,Civil and Structural Engineering - Abstract
The majority of existing cyclic stress–strain models for fiber reinforced polymer (FRP) confined concrete are applicable only to cases where post-peak strain hardening occurs. Cyclic model catering for strain softening is rare due to the lack of sufficient experimental data. Recent experimental tests on FRP-confined concrete cylinders involving strain-softening have identified new factors that have a significant effect on the cyclic behavior. Through an analytical study, a newly defined parameter, the effective confinement rigidity, is found to be a key factor governing the cyclic softening and hardening. By including the additional key factors and using the latest database with more strain-softening cyclic stress–strain curves, a stress–strain model of FRP-confined concrete subjected to cyclic loading considering both post-peak hardening and softening is proposed. Compared with the existing models, the proposed model can predict the cyclic behavior of FRP-confined concrete with better accuracy.
- Published
- 2018
39. Proposing a Cyclic Model of Tourist Decision Making: A Review and Integration of Behavioral and Choice-Set Models
- Author
-
Ruizhe Fang
- Subjects
Cyclic model ,Choice set ,Operations research ,Computer science ,Tourism, Leisure and Hospitality Management ,Tourism ,Education - Abstract
Tourist decision studies focus on modeling decision-making behaviors, conceptualizing phases in decision making, and influential factors. Incorporating behavioral and choice-set model strategies, the current study proposes a generalizable cyclic model of tourist decision-making processes with a structure of repeatable behavioral stages integrated with relevant consideration sets. A “decision-making threshold” and “information loop limit” are introduced to control how and when the decision-making process starts or ends. The proposed model makes it possible to represent different decision-making styles by capturing the dynamic repetition of behavioral stages and the revision of consideration sets. The integration allows a novel approach for analyzing the formation of final decisions resulting from decision makers’ limited subjective evaluations and for studying decision rules as the combinations of “evaluation rule” and “information loop limit.” Practical implications and measures are provided for tourism practitioners to better understand and influence potential consumers. Future research questions are also suggested.
- Published
- 2021
40. Cyclic shear displacement model for reinforced concrete columns
- Author
-
Halil Sezen and Erkan Bicici
- Subjects
Cyclic model ,Materials science ,business.industry ,Stiffness ,Structural engineering ,Shear (sheet metal) ,OpenSees ,Flexural strength ,medicine ,Displacement (orthopedic surgery) ,Slippage ,medicine.symptom ,business ,Envelope (mathematics) ,Civil and Structural Engineering - Abstract
Lateral response of reinforced concrete (RC) columns can be modeled and simulated considering three displacement components: flexural displacement, displacement due to slippage of longitudinal bars at column ends, and shear displacement. The incorporation of shear displacement in a computational model is essential for accurate calculation of lateral load–displacement relationship. The contribution of shear displacement can be significant for RC columns with low displacement capacity or ductility. An easy-to-apply shear displacement model is proposed in this study, and implemented in the open source software, OpenSees. The proposed model is based on a pre-defined envelope or monotonic model and does not require updating of modeling parameters during each cycle. The model is validated using experimental data. New rules are developed for the cyclic model to capture the effects of cracking and change in stiffness and strength during the loading and unloading cycles. Comparison of the calculated and measured shear displacements indicates that the cyclic shear response can be captured by the proposed model.
- Published
- 2021
41. Cyclic stress-strain model incorporating buckling effect for steel reinforcing bars embedded in FRP-confined concrete
- Author
-
Jian-Guo Dai, Togay Ozbakkaloglu, and Yu-Lei Bai
- Subjects
Cyclic model ,Cyclic stress ,Materials science ,business.industry ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,Structural engineering ,Fibre-reinforced plastic ,0201 civil engineering ,Transverse plane ,OpenSees ,Buckling ,021105 building & construction ,Ceramics and Composites ,Composite material ,Reinforcement ,Envelope (mathematics) ,business ,Civil and Structural Engineering - Abstract
Buckling of steel reinforcement usually causes a sudden loss of the load-carrying capacity and the ultimate state of conventional reinforced concrete (RC) cylinders. However, reinforcing bars behave differently in fiber-reinforced polymer (FRP)-confined RC cylinders due to the lateral confinement effect of FRP. This paper presents a theoretical study into the buckling behavior of longitudinal steel reinforcing bars embedded in FRP-confined concrete subjected to cyclic axial compression. An empirical monotonic compressive stress-strain model considering the buckling effects proposed previously for laterally supported reinforcing bars is extended to a cyclic model by combining the monotonic envelope and the Menegotto-Pinto model accounting for the cyclic loops. The cyclic stress-strain models for both laterally supported reinforcing bars and FRP-confined plain concrete are then implemented into the OpenSees software platform and validated through comparisons with compressive test results on cyclically loaded FRP-confined plain and RC cylinders. The proposed cyclic stress-strain model for laterally supported reinforcing bars is expected to serve as a fundamental model for predicting the seismic behavior of FRP-strengthened RC cylinders with widely-spaced transverse ties under cyclic axial compression, in which case the local buckling of reinforcing bars usually occurs between two adjacent transverse ties.
- Published
- 2017
42. Two Layer Model for Performance Evolution of V2I Network.
- Author
-
Bogdanovs, N., Petersons, E., and Jansons, J.
- Subjects
COMPUTER networks ,BIT rate ,IEEE 802.11 (Standard) ,VEHICULAR ad hoc networks ,DATA analysis ,MATHEMATICAL models ,PERFORMANCE evaluation - Abstract
This research presents data evaluating data transfer rate between a remote object and base station in wireless network standard 802.1g/n. Regularity was observed in data transfer rate dependency from the M number of remote objects. All measurements and conclusions were made under circumstances where objects were positioned stationary relative to base station. As the result of the experiment, the mathematical models for two layer wireless networks and closed cyclic wireless networks were selected as ones who are to be used for choosing an optimal method for performance evaluation of a short range communication vehicular network. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
43. PERSISTENCE OF BLACK HOLES THROUGH A COSMOLOGICAL BOUNCE.
- Author
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CARR, B. J. and COLEY, A. A.
- Subjects
- *
BLACK holes , *GRAVITATIONAL collapse , *QUANTUM gravity , *ASTRONOMICAL observations , *ASTROPHYSICS , *METAPHYSICAL cosmology - Abstract
We discuss whether black holes could persist in a universe which recollapses and then bounces into a new expansion phase. Whether the bounce is of classical or quantum gravitational origin, such cosmological models are of great current interest. In particular, we investigate the mass range in which black holes might survive a bounce and ways of differentiating observationally between black holes formed just after and just before the last bounce. We also discuss the consequences of the universe going through a sequence of dimensional changes as it passes through a bounce. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
44. Modeling and seismic response of structures with concrete rocking columns and viscous dampers
- Author
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Roh, Hwasung and Reinhorn, Andrei M.
- Subjects
- *
EARTHQUAKE resistant design , *STRUCTURAL analysis (Engineering) , *DAMPERS (Mechanical devices) , *STRENGTH of materials , *CONCRETE , *STIFFNESS (Engineering) , *STRAINS & stresses (Mechanics) , *NONLINEAR statistical models - Abstract
Abstract: The maximum acceleration response of a simple yielding structure is proportional to its structural strength. Therefore, in order to reduce accelerations, the overall strength of the structure should be decreased while controlling possible resulting increases of displacements with supplemental damping. The use of “rocking columns”, a type of double hinged gravity column, is suggested to reduce the strength of part of the lateral resisting system. A simplified analytical model of the columns represented by a moment–curvature relationship and a stiffness matrix, verified through experiments, is developed and implemented in the structural analysis program IDARC2D. The experimental study done on rocking concrete columns is briefly presented to show their global behavior and adjust the simplified model. For dynamic analysis, nonlinear stress zone approach and hysteretic models are also developed. A numerical study is conducted to demonstrate that story acceleration responses can be reduced compared to conventional structures, while the increased displacements are controlled using supplemental viscous dampers. A 1/3 scaled model structure, previously tested at the University at Buffalo, is used to evaluate the global seismic behavior of weakening alternatives modified using rocking columns and added viscous dampers. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
45. Modelling systems with renewable resources based on functional operators with shift
- Author
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Tarasenko, Anna, Karelin, Aleksandr, Pérez Lechuga, Gilberto, and González Hernández, Manuel
- Subjects
- *
MATHEMATICAL models , *RENEWABLE energy sources , *OPERATOR theory , *DISCRETE-time systems , *FUNCTIONAL equations , *EXISTENCE theorems - Abstract
Abstract: A method for the study of systems with renewable resources is proposed. The individual and the group parameters are separated and a discretization of time is carried out. We obtain equilibrium proportions which are functional equations with shift. A cyclic model and an open model are considered. Conditions for the existence and uniqueness of the solution are formulated for the cyclic model. For the open model, the system’s evolution is analyzed. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
46. Cyclic shear displacement model for reinforced concrete columns.
- Author
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Bicici, Erkan and Sezen, Halil
- Subjects
- *
REINFORCED concrete , *OPEN source software , *CYCLIC loads , *LATERAL loads , *CONCRETE columns , *CONCRETE fatigue , *CONCRETE beams - Abstract
• Lateral displacement of concrete columns is sum of flexural, slip and shear displacements. • A new cyclic shear displacement model is proposed. • The proposed model is implemented in an open-source structural analysis software (OpenSees). • Column lateral displacement under cyclic loading is accurately calculated with the proposed model. Lateral response of reinforced concrete (RC) columns can be modeled and simulated considering three displacement components: flexural displacement, displacement due to slippage of longitudinal bars at column ends, and shear displacement. The incorporation of shear displacement in a computational model is essential for accurate calculation of lateral load–displacement relationship. The contribution of shear displacement can be significant for RC columns with low displacement capacity or ductility. An easy-to-apply shear displacement model is proposed in this study, and implemented in the open source software, OpenSees. The proposed model is based on a pre-defined envelope or monotonic model and does not require updating of modeling parameters during each cycle. The model is validated using experimental data. New rules are developed for the cyclic model to capture the effects of cracking and change in stiffness and strength during the loading and unloading cycles. Comparison of the calculated and measured shear displacements indicates that the cyclic shear response can be captured by the proposed model. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
47. A Cyclic Model of Universe with Energy Exchange between Radiation, Matter and Vacuum Energy.
- Author
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Guang-Wen Ma and Jing-Yuan Ma
- Subjects
- *
ACCELERATION (Mechanics) , *ASTRONOMY , *RADIATION , *FLUID mechanics , *VACUUM - Abstract
We further extend the cosmological scenario with energy exchange by Barrow and Clifton and our previous work to the more complex case with energy exchange between three fluids: radiation, matter and vacuum energy. By prescribing the form of energy exchange function, we construct an infinitely cyclic cosmological model, in which the universe undergoes an endless sequence of cosmic epoch and each consisting of expansion and contraction, and the cosmological parameters, such as the Hubble parameter H, deceleration parameter q, transition red-shift Z T, and densities ρ r , ρ m , and ρ Λ are consistent with the present observed values. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
48. Experimental analysis and modelling of bolted T-stubs under cyclic loads
- Author
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Piluso, Vincenzo and Rizzano, Gianvittorio
- Subjects
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MECHANICAL loads , *BOLTED joints , *SEALING (Technology) , *SOLDER & soldering - Abstract
Abstract: Bolted connections have recently attracted new research efforts after the unexpected failures of welded connections during Northridge and Kobe earthquakes. The criteria and the formulations for predicting the rotational stiffness and the flexural resistance, under static loading conditions, of the most common connection typologies have been codified by Eurocode 3 [CEN. EN 1993-1-8 Eurocode 3: Design of steel structures — Part 1.8 Design of joints. 2005] which is based on the so-called component approach. In order to extend the component approach to the prediction of the seismic response of partial-strength connections, the modelling of the cyclic response of the joint components is necessary. Starting from the observation that the main sources of deformability and plastic deformation capacity of bolted connections can be modelled by means of an equivalent T-stub, an experimental program devoted to the cyclic response of the most important component of bolted connections has been carried out aiming at the modelling of the cyclic force–displacement curve of bolted T-stubs. In this paper, starting from the analysis of the results of the experimental tests performed, stiffness and strength degradation rules are derived as a function of the displacement amplitude required at any cycle and of the energy dissipated in the previous loading history. The combination of these rules with the theoretical prediction of the monotonic envelope leads to a proposal for predicting the cyclic behaviour of bolted T-stubs starting from the knowledge of their geometrical and mechanical properties. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
49. COSMOLOGY IN NONLINEAR BORN–INFELD SCALAR FIELD THEORY WITH NEGATIVE POTENTIALS.
- Author
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FANG, WEI, LU, H. Q., and HUANG, Z. G.
- Subjects
- *
DARK energy , *FORCE & energy , *METAPHYSICAL cosmology , *METAPHYSICS , *ASTRONOMY , *SCALAR field theory - Abstract
The cosmological evolution in Nonlinear Born–Infeld (hereafter NLBI) scalar field theory with negative potentials was investigated. The cosmological solutions in some important evolutive epoches were obtained. The different evolutional behaviors between NLBI and linear (canonical) scalar field theory have been presented. A notable characteristic is that NLBI scalar field behaves as ordinary matter nearly the singularity while the linear scalar field behaves as "stiff" matter. We find that in order to accommodate current observational accelerating expanding universe the value of potential parameters |m| and |V0| must have an upper bound. We compare different cosmological evolutions for different potential parameters m, V0. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
50. Invariant integral: The earliest works and most recent application
- Author
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G. P. Cherepanov
- Subjects
Physics ,Cyclic model ,Big Bang ,Ultimate fate of the universe ,Big Rip ,02 engineering and technology ,Surfaces and Interfaces ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Physical cosmology ,020303 mechanical engineering & transports ,Classical mechanics ,0203 mechanical engineering ,Mechanics of Materials ,De Sitter universe ,0103 physical sciences ,General Materials Science ,Invariant (mathematics) ,Big Bounce - Abstract
The present paper embraces mainly the three-year period of 1966 to 1968 when the invariant integral of fracture mechanics appeared and became popular, and the last two years of 2015 to 2016 when the neoclassic cosmology based on the invariant integral came up. A mention is given to the previous works of Euler, Cauchy, Maxwell, Nother, Gunther and Eshelby who dealt with invariant integrals in mathematics, hydrodynamics, electrodynamics, and the theory of dislocations. A brief review is given of the creation of the invariant integral of fracture mechanics under static and dynamic conditions for a solid continuum including elastic, plastic and viscoelastic materials, as well as of some of its most important applications, ramifications and generalizations for other physical fields. The initial phase of the expansion and revolution of the large-scale universe is studied in the framework of the neoclassic approach, including the Big Bang and the Dark Energy; it is shown that the spheroidal shape of the universe assumed at the Big Bang retains its eccentricity constant in the initial phase. The assumption of a superphoton as a primordial universe was analyzed.
- Published
- 2017
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