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Wyszukujesz frazę "imperfection" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Some selected FEM analyses of motion of a bullet with imperfections while interacting with the barrel
Autorzy:
Łazowski, J.
Małachowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/243313.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
barrel
bullet
simulation
movement modelling
imperfection
Opis:
The intended aim of studies on the modelling of a bullet interacting with a barrel is to generale a virtual, computer-based model, experimentally verified for some selected mating conditions, and to become able to predict -with strong probability - processes and phenomena that take place within a system with imperfections. In the case under consideration the problem of contact between the barrel and the bullet has been described with the calculation method based on the penalty function. Calculations were made using the so-called direct-integration procedurę, colloquially called the ,,explicit integration ". Preliminary analysis has been carried out on the effect of the shift of the centre ofmass of the bullet moving in the barrel. Simulation included the bullet displacement along the barrel's axis, with the assumed positions of the centre ofmass -5% and +5% as measured from the bottom and referred to the initial model (0%). Results ofnumerical calculations suggest the effect of shift of the bullet's centre of mass, which -when exposed to complex states of loading - experiences oscillating movements of the bottom and the tip. Additionally, this analysis proves that there is a complex state of stress due to compression, torsion, and bending of the bullet while interacting with the inner part of the barrel. Numerical solutions may support the analytically approached solving of such mechanical system. They may also offer more precise determination of, e.g. initial and boundary conditions for the bullet 's free flight, which is of great significance to the accuracy of fire, and therefore, to the weapons effectiveness.
Źródło:
Journal of KONES; 2008, 15, 1; 145-152
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some selected examples of fem modelling of structure-affecting material and manufacturing faults
Autorzy:
Jachimowicz, J.
Małachowski, J.
Krasoń, W.
Kajka, R.
Powiązania:
https://bibliotekanauki.pl/articles/243333.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
FEM modelling
combustion engine
landing gear
imperfection
Opis:
In design practice, in most of cases, stresses and deformations of structures with nominal dimensions and average material properties were analyzed. It have been concluded that such procedure is most often sufficient. However, there are design solutions, especially in high-effort structures for example aircraft and turbine engines, where scatter of geometrical dimensions consistent with assumed tolerances cause significant scatter of stresses and strains, differ from values coming from nominal dimensions. Scatter of these values have essential influence on service life of presented structures. Example of such effect is described in the paper. There were used FEM analyses to determination of scatter of stresses and stres s concentration coefficient in herringbone lock joint of K-15 engine's turbine. Another example of fault impact on stresses in structure is analysis of undercarriage element with material fault. Both these examples indicate on great sensitivity of stress distribution on manufacturing imperfections. The impact of these faults and imperfections reaches hundreds of per cent, and in some cases could be serious menace of operating safety. In structures with the multiple 3D stress state, non-linear geometric and material phenomena, with contact between friction-affected elements, any geometric imperfections can cause considerable local changes in the stress and strain.
Źródło:
Journal of KONES; 2008, 15, 1; 97-107
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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