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Wyszukujesz frazę "Romanowicz, P." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Application of 3-D fracture criteria for assessment of fatigue strength of composite plate with internal delamination
Autorzy:
Romanowicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/242045.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
aircraft engineering
mechanical engineering
Opis:
The fracture analysis of the composite plates with circular delaminations working in a regime of cyclic multi-axial stresses is the main object of the paper. Such structures with internal damage are mainly exposed for local or global buckling and delamination propagation under service loadings. Analyses of described phenomena are complex and require application of fracture mechanics and nonlinear analysis. The literature review of experimental and theoretical investigations of composite plates with circular delaminations is presented in the paper. The essential papers including experimental fatigue tests and theoretical techniques for studying of damage propagation growth are cited and crucial conclusions are given. In composite structures with internal delamination, the cyclic compression-tension and compression-compression stresses are the most dangerous. Moreover, the rapid increase of damage propagation occurs in the final stage of structure degradation. Such problem is investigated and illustrated on the example of rectangular plate with the circular delamination. The calculations are made for bi-axial compression and AS4/3501-6 graphite/epoxy material. The fracture analysis is made using different criteria based on the linear elastic fracture mechanics. The criteria are compared with the multiaxial experimental tests made for AS4/3501-6 graphite/epoxy material. It is observed that in composite plate with the internal delamination subjected for compressive loading the complex form of the gap opening occur. Because of this, the 3-D fracture criteria are applied in the investigations. Presented methodology allow for suitable selection of the multiaxial fracture model for analysis of such structures including interactions between different forms of the gap opening. The critical loadings for different layers orientation are estimated and given in the paper.
Źródło:
Journal of KONES; 2016, 23, 2; 301-308
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of crack presence on operating conditions of pressure vessels with flat endplates
Autorzy:
Szybiński, B.
Romanowicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/242804.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
pressure boilers
flat ends
cracks
fracture analysis
FEM
Opis:
The paper discusses influence of crack presence on operating conditions of boilers and pipes. In the study particular attention is paid to the vessels with flat endplates with circular stress relieve grooves. The endplates with such grooves are common alternative for widely used dished ends, particularly for smaller boiler diameters and also for vessels with non-circular cross-sections. The existing codes set the rules how to calculate the circular groove parameters – the groove radius and the location of the arc centre. These design parameters are limited by set of inequalities, which indicate the ranges for admissible radii values and the groove centre positions. The choice of the optimal values for the endplate design parameters has been worked out in recent Authors’ investigations. Such approach provides the minimum stress concentration in the vicinity of the cutout, but this notch area still can be the source of crack nucleation and its propagation leading to the premature fracture of the considered vessel. In standard calculations of pressure boilers, the fracture parameters are not taken into account. The current study concentrates on the assessment of the influence of the crack existence on the stable vessel operation. The cracks existing in inner wall of the vessel are of the main interest, because these are difficult to identify and monitor. In these studies the influence of different parameters like the crack length and orientation, and the fracture toughness were taken into account. The detailed numerical results were obtained by means of the finite element code ANSYS [1] for several crack sizes and locations. The cracks in the weld joining shell and end plate and cracks in the groove area, where the maximum stress concentration appeared were subject of the numerical study. The obtained results show the risk of possible premature failure of boilers with cracks.
Źródło:
Journal of KONES; 2016, 23, 1; 377-384
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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