Wyniki wyszukiwania - BazTech

1

Mechanical Compression Behaviour of "Green" Rocket Propellants

Dîrloman Florin M., Rotariu Traian, Rotariu Adrian N., Toader Gabriela, Matache Liviu C., Noja Gabriel F.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

|

2023

|

Vol. 14, Nr 2 (52)

9--18

EN

The issues related to mechanical resistance of solid rocket propellants, which can appear during storage or handling of the launching system, are considered to directly influence the burning performance. Thus, in this study, four new types of composite rocket propellants, based on an environmentally friendly oxidizer (phase-stabilized ammonium nitrate), a metallic fuel (aluminium), and a "green" polyurethane-based binder (synthesized from an oligomeric isocyanate and a blend of polyester-polyols obtained through the catalytic degradation of polyethylene terephthalate), were subjected to compression mechanical analysis in order to highlight the importance of the binder on the response given by the tested materials subjected to compressive loads. The samples showed remarkable mechanical performances, the experiments allowing us also to determine the influence of the binder composition and fuel granulation on mechanical properties of the composite propellant.

2

Design and mechanical analysis of a composite T-type connection structure for marine structures

Li Xiaowen, Zhu Zhaoyi, Li Yan, Hu Zhe

Polish Maritime Research

|

2020

|

nr 2

145--157

EN

A new T-type connection structure consisting of composite sandwich plates, reinforced cores and adhesive was proposed for the construction of lightweight ships to resolve connection problems between bulkheads and decks of composite lightweight ship superstructures. Based on the design principles and mechanical properties of composite structures, the mechanical behaviour of the structure under a dangerous loading condition was investigated. In addition, the ultimate bearing capacities and damage modes were examined, the results of which demonstrated that the strength of the structure is weak, and that the adhesive and reinforced core between the face plate and the web plate is the primary weakness of the structure. A numerical simulation method was verified using the results of the mechanical tests, and five characteristic paths at the connection area were established. The stresses and displacements along the five paths were calculated using the numerical method. Then, variations in the geometric parameter and the strength and weight of the connection were summarised. The optimal angle of the adhesive bonding area is approximately 60°, which supports the optimal design and practical application of the lightweight ship adhesive-bonded connection structure.

3

Projekt i analiza wytrzymałościowa modelu mostu

Sosnowski M., Skupiński A.

Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Technika, Informatyka, Inżynieria Bezpieczeństwa

|

2015

|

T. 3

245-252

PL

W ramach pracy zaprojektowano i wykonano model konstrukcji mostowej jak również przeprowadzono badania eksperymentalne dotyczące wytrzymałości opracowanej koncepcji. Ponadto równolegle zrealizowano numeryczną analizę wytrzymałościową wirtualnego modelu opracowanego mostu oraz dokonano porównania wyników badań numerycznych i eksperymentalnych.

EN

The bridge model was designed and manufactured within the conffines of the work. The experimental research as well as numerical analysis concerning the mechanical strength of the developed design were performed. The comparison of experimental and numerical research results is presented in the paper.

4

Mechanisms and mechanics of porosity formation in ductile iron castings

Perzyk M., Witemberg-Perzyk D.

Archives of Foundry Engineering

|

2007

|

Vol. 7, iss. 4

147-150

EN

Shrinkage defects in ductile iron castings can be of two basic types: shrinkage cavities associated with the liquid contraction prior to the expansion period of the iron as well as the porosity, which may appear even if the liquid shrinkage is fully compensated. In the present paper two possible mechanisms of the porosity are presented and analyzed. The first one is the Karsay's mechanism based on the secondary shrinkage concept. The second one is the mechanism acting during the expansion period of the iron, first suggested by Ohnaka and co-authors and essentially modified by the present authors. The mechanical interactions between casting and mould are determined for the both mechanisms. Their analysis leads to the conclusion, that porosity forms during expansion period of the melt. The direct cause is the negative pressure which appears in the central part of the casting due to the differences in expansion coefficients of the fast cooling surface layer and slow cooling inner region. Observations concerning feeding behavior of ductile iron castings, based on this mechanism, agree well with industrial practice. The secondary shrinkage is not only needless to induce the porosity, but the corresponding mechanism of its occurrence, proposed by Karsay, does not seem to be valid.