Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: thermal interactions

Sortuj według:

Ogranicz wyniki do:

Modeling of temperature field inside the tissue with a blood vessel using the BEM-FDM algorithm

100%

Majchrzak E. , Borowska J. , Klekot J. , Tarasek D.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

2012

tom Vol. 11, nr 4

85-92

The thermal interactions between the blood vessel and surrounding biological tissue are analyzed. The tissue temperature is described by the Pennes equation, while the equation determining the change of blood temperature along the blood vessel is formulated on the basis of adequate energy balance. These equations are coupled by a boundary condition given at the blood vessel wall. The problem is solved using the hybrid algorithm, this means the temperature field in biological tissue is determined by means of the boundary element method (BEM), while the blood temperature is determined by means of the finite difference method (FDM). In the final part the examples of computations are presented.

Influence of temperature changes on stresses in carbon composite fastening bolts

100%

Arkuszyńska A. , Godzimirski J. , Rośkowicz M.

Technologia i Automatyzacja Montażu

2024

tom nr 2

3--10

High joint strength of composite structures can be achieved by using mechanical fasteners. The materials used for rivets and bolts have lower coefficients of thermal expansion than composites in the direction perpendicular to the reinforcement fibers. It is suspected, therefore, that temperature changes can cause stress changes in mechanical fasteners. The purpose of this study was to experimentally determine and analytically substantiate the values of stress changes resulting from a change in temperature in the range from -20 to 60C in M8 steel bolts fastening carbon composite. The value of stress changes was estimated to be around 100 MPa, which can consequently lead to joint unsealing or plastic deformation of the mechanical fastener.

Wysoka wytrzymałość połączeń struktur kompozytowych może zostać osiągnięta dzięki zastosowaniu łączników mechanicznych. Materiały wykorzystywane do produkcji nitów oraz śrub cechują mniejsze wartości współczynników rozszerzalności cieplnej niż kompozytów w kierunku prostopadłym do włókien zbrojenia. Podejrzewa się więc, że zmiany temperatury mogą powodować zmiany naprężeń w łącznikach mechanicznych. Celem przeprowadzonych badań było eksperymentalne określenie i analityczne uzasadnienie wartości zmian naprężeń wynikających ze zmiany temperatury w zakresie od -20 do 60C w stalowych śrubach M8 łączących kompozyt węglowy. Wartość zmian naprężeń oszacowano na około 100 MPa, co w konsekwencji może prowadzić do rozszczelnienia połączenia lub plastycznych odkształceń łącznika mechanicznego.

Investigation of thermal interactions between elements of propulsion system and selected parts of the airplane skin in small aircrafts

80%

Łapka P. , Seredyński M. , Furmański P.

Archives of Thermodynamics

2018

tom Vol. 39, no 3

45--61

Development of new or upgrading of existing airplanes requires many different analyses, e.g., thermal, aerodynamical, structural, and safety. Similar studies were performed during re-design of two small aircrafts, which were equipped with new turboprop engines. In this paper thermo-fluid analyses of interactions of new propulsion systems with selected elements of airplane skin were carried out. Commercial software based numerical models were developed. Analyses of heat and fluid flow in the engine bay and nacelle of a single-engine airplane with a power unit in the front part of the fuselage were performed in the first stage. Subsequently, numerical simulations of thermal interactions between the hot exhaust gases, which leave the exhaust system close to the front landing gear, and the bottom part of the fuselage were investigated. Similar studies were carried out for the twin-engine airplane with power units mounted on the wings. In this case thermal interactions between the hot exhaust gases, which were flowing out below the wings, and the wing covers and flaps were studied. Simulations were carried out for different airplane configurations and operating conditions. The aim of these studies was to check if for the assumed airplane skin materials and the initially proposed airplane geometries, the cover destruction due to high temperature is likely. The results of the simulations were used to recommend some modifications of constructions of the considered airplanes.