Wyniki wyszukiwania - BazTech

1

Stability and failure of thin-walled composite structures with a square cross-section

Czajka Błażej, Różyło Patryk, Dębski Hubert

Applied Computer Science

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2022

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Vol. 18, no 2

43--55

EN

This paper is devoted to the analysis of the stability and load-carrying capacity of thin-walled composite profiles in compression. The specimens reflect elements made of carbon fibre reinforced laminate (CFRP). Thin-walled columns with a square cross-section were made from 4 layers of composite in 3 different combinations of layer arrangements. Advanced numerical analyses have been carried out. In the first stage of the study, a buckling analysis of the structure was performed. In further numerical simulations, two advanced models were used simultaneously: the Progressive Failure Analysis (PFA) and the Cohesive Zone Model (CZM). The results showed significant differences between the critical load values for each layer configuration. The forms of buckling and the areas of damage initiation and evolution were also dependent on the applied layup.

2

Research on hybrid modified pathfinder algorithm for optimal reactive power dispatch

Suresh V., Senthil Kumar S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 4

art. no. e137733

EN

Hybridization of meta-heuristic algorithms plays a major role in the optimization problem. In this paper, a new hybrid meta-heuristic algorithm called hybrid pathfinder algorithm (HPFA) is proposed to solve the optimal reactive power dispatch (ORPD) problem. The superiority of the Differential Evolution (DE) algorithm is the fast convergence speed, a mutation operator in the DE algorithm incorporates into the pathfinder algorithm (PFA). The main objective of this research is to minimize the real power losses and subject to equality and inequality constraints. The HPFA is used to find optimal control variables such as generator voltage magnitude, transformer tap settings and capacitor banks. The proposed HPFA is implemented through several simulation cases on the IEEE 118-bus system and IEEE 300-bus power system. Results show the superiority of the proposed algorithm with good quality of optimal solutions over existing optimization techniques, and hence confirm its potential to solve the ORPD problem.

3

Preparation and properties of carbon/carbon and polymer/carbon porous monolithic composites

Krzesińska M.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 1

45--53

EN

Purpose: An overview of own works on preparation of monolithic carbon/carbon and polymer/carbon composites, that were fabricated using natural biological precursors for both composite components: carbonized plant stem for a support and chitosan or furfuryl alcohol for a filler, is presented. Composites based on monolithic porous supports prepared from expanded graphite are also discussed. Design/methodology/approach: The supports were prepared by carbonization of plants stems or by compression of expanded graphite. Next step was infiltration with the polymers, that were cross-linked on the supports. The structure and properties of the supports and the composites were characterized using numerous experimental techniques: thermogravimetry, helium gas densitometry, mercury porosimetry and adsorption of N2 gas, ultrasonic and electrical measurements, FTIR, EPR and observed with microscopes: optical, SEM and TEM. Findings: The carbon based composites were found to exhibit properties of the polymeric fillers, as well as electrical conductivity and high stiffness of monolithic carbon framework. Practical implications: The materials could be utilized as adsorbents/absorbents, catalysts supports, sensors, filters, etc. Originality/value: New class of original biodegradable bio-composites in the form of monoliths of optional shapes was obtained in contrast to adsorbents usually fabricated as granules or to composites being resins fulfilled by granules or fibres.

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Analiza składowych głównych - narzędzie również dla inżynierów

Stasiak M.

Nowa Elektrotechnika

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2006

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nr 4 (20)

6--7