Wyniki wyszukiwania - BazTech

1

Validation of the continuum orthotropic model of tensegrity beam-like and plate-like structures

Obara P., Tomasik J.

Archives of Mechanics

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2023

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Vol. 75, nr 3

249--269

EN

In this paper, an attempt was made to develop the continuum orthotropic model of tensegrity structures. A basic four-module tensegrity grid built from modified Quadruplex modules was proposed. A procedure called the energy equivalency method was adopted. The basis of this approach is the assumption that the finite element strain energy of a deformed tensegrity truss system contains the same energy as its continuum counterpart. Next, the six-parameter shell theory was used and closed forms for maximum displacements were obtained. Finally, in order to fill the gap in the existing literature, the continuum model was validated – the displacements were compared with displacements obtained from a discrete nonlinear model (the finite element method). The continuum model of tensegrity is a simple tool for analyzing large beam-like structures, plate-like structures and plate strips. It is important in case when discrete modeling becomes too tedious for the analysis. Another point is that many commercial software programs cannot analyze structures characterized by mechanisms. The finding of this work can also be useful for modeling metamaterials whose topology is based on the concept of tensegrity.

2

Service behaviour of the self-stressed members reinforced with FRP bars

Semianiuk Volha, Semianiuk Siarhei, Tur Victar

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

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2020

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Nr 2

1--10

EN

Fiber reinforced polymer (FRP) bars, as a structural reinforcement, are characterized by the number of advantages, such as: high strength-to-density ratio; absence of corrosion; resistance to the negative influence of the different aggressive mediums. Nevertheless, a wide practical application of such a bars finds an embarrassment because of the law modulus of elasticity (it varies from 30 GPa to 60 GPa), that leads to the development of the excessive crack opening as well as deflections under the loading. To enhance structural performance of the FRP reinforced concrete members, pretensioning of FRP bars can be considered as a good option. Opposite to the concrete members mechanical pretensioning, physico-chemical method of bars pretensioning based on the self-stressing concrete utilizing is considered. Influence of the controlled initial stress-strain state obtained during early age concrete expansion on the mechanical resistance of the self-stressed concrete members reinforced with both steel and FRP bars was studied.

3

Strains and self-stresses estimation in the expansive concrete members reinforced with GFRP bars

Tur V., Semianiuk V.

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

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2016

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Nr 4

3--9

EN

Advantages of the self-stressed concrete members with FRP reinforcement are described. Analytical model for the restrained expansion strains (self-stresses) estimation in the self-stressed concrete members reinforced with FRP bars is proposed. Established modified strains development model (MSDM) is based on deformation compatibility approach in combination with taking into account imposed internal force in reinforcement as an additional restriction for the expansion strains development. Comparison of experimentally established and predicted data that was obtained in accordance with the proposed model for the case of GFRP bars uniaxially symmetrically reinforced high expansion energy capacity concrete members is presented. Verification of the proposed MSDM has shown a good agreement between calculated and experimental values that indicates its validity for the design of the self-stressed concrete members with GFRP reinforcement.

4

On possible applications of smart structures controlled by self-stress

Gilewski W., Al Sabouni-Zawadzka A.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 2

469--478

EN

Civil Engineering (CE) is one of the many fields of possible implementation of smart or intelligent technologies. The present paper is an attempt to specify and estimate problems and areas of CE suitable for the application of such technologies, with the focus on Bridge Engineering (BE). Precise definitions, explanations and classifications of terms used in smart technique are introduced and components of smart systems are defined. Analogies between smart systems and biological ones are indicated. The paper presents some of the research projects carried out in the field of CE, according to the current state-of-the-art. Concepts of smart bridges are proposed and several examples of structural control performed on space trusses and tensegrity structures with self-stress are introduced. Examples of structural control presented in the paper show that characteristic displacements of the analysed structures may be reduced by changing the prestressing force applied to the single modules, which are a part of the structure. Results of the performed analysis indicate that tensegrity structures are much more prone to the changes in the value of prestressing force than truss structures, which makes them a promising solution as far as structural control is concerned.