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An optimal design of thermal protection basedon materials morphology

Salosina Margarita O., Alifanov Oleg M., Nenarokomov Aleksey V.

Computer Assisted Methods in Engineering and Science

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2019

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Vol. 26, no. 1

49--60

EN

The paper presents a methodology for the optimal design of multilayer thermal protection based on high-porosity open-cell foam, taking into account the foam morphology. The vector of design parameters includes the thicknesses of layers, porosity and cell diameter of open-cell foam and should ensure required operation temperature on the boundaries of layers and a minimum of the total mass of the system. The optimization problem is solved using a computational scheme, which combines the projected Lagrangian method with the quadratic subproblem and the penalty function method. The penalty function method provides a good initial estimate of the optimal parameters’ values for the projected Lagrangian method with excellent local convergence properties. To illustrate the implementation of the developed algorithm and the corresponding software, the problem of choosing the optimal layer thicknesses for the multilayer thermal protection of a spacecraft along with the cell diameter and porosity of foam is considered.

2

Low-velocity impact behaviour of open-cell foams

Hedayati R., Sadighi M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 4

939--949

EN

Metal foams are cellular solids that show some unique properties which cannot be found in other natural or human-made materials. While the impact characteristics of closed-cell foams under static and impact loadings appear to be well-studied in the literature, the impact behaviour of open-cell foams is not yet well-understood. In this study, open-cell foams with two different densities are impacted by drop weights with different kinetic energies. The effects of foam density, impactor initial height, and impactor weight on the recorded stresstime, stress-strain, and energy-strain curves are investigated. While the stress-strain curve of closed-cell foams under impact loading usually consists of a single bell, the results of the current study showed that both the stress-time and stress-strain curves of most the samples consist of two consecutive bells. By increasing weight of the impacting weight, the number of bells increases which helps in increasing the impact period and keeping the maximum generated stress low. Compared to closed-cell foams, the open-cell foams can therefore better absorb the energy, as long as the impact energy is relatively small. The relatively low stiffness as well as the presence of large hollow space inside the open-cell foams also makes them favorable for being used as biomedical scaffolds.

3

Piana PUR i polimocznik – innowacyjne izolacje natryskowe

Matusiak A., Szafran J.

Inżynier Budownictwa

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2018

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nr 4

45--50

PL

Nowoczesne budownictwo generuje nowe i nieprzeciętne wymagania względem stosowanych materiałów budowlanych. Dotyczy to również wyrobów wykorzystywanych do izolacji termicznej, hydroizolacji oraz izolacji przeciwwilgociowej. Tu rozwiązaniem mogą być nowoczesne izolacje natryskowe w postaci piany PUR i polimocznika. W artykule zaprezentowano podstawowe ich właściwości, również w kontekście konkurencyjności w stosunku do tradycyjnych ich odpowiedników.

EN

Modern construction generates new and demanding requirements regarding building materials. This also applies to products used for thermal insulation, waterproofing and damp proofing. The solution here might be modern spray insulation in the form of PUR foam and polyurea. The article presents their basic properties, while emphasising their competitive advantage over their traditional counterparts.