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Badania dwubazowego paliwa rakietowego za pomocą dynamicznej analizy mechanicznej

100%

Cegła M. , Zmywaczyk J. , Koniorczyk P.

tom R. 43, z. 131

49--55

W artykule przedstawiono wyniki badań stałego dwubazowego paliwa rakietowego za pomocą dynamicznej analizy mechanicznej (DMA). Autorzy wykonali badania właściwości mechanicznych takich jak dynamiczny moduł zachowawczy (E'), dynamiczny moduł stratności (E'') oraz tanδ (E''/E'). Ich charakterystyki temperaturowe zostały wyznaczone za pomocą urządzenia Netzsch DMA 242C w zakresie temperatury od -120°C do +90°C przy szybkości ogrzewania wynoszącej 1K/min lub 2K/min. Próbka zamocowana była w uchwytach typu podwójny wspornik (dual-cantilever) i poddana obciążeniom o częstotliwości 1Hz. Szczególną uwagę poświęcono właściwemu doborowi parametrów i wymiarów próbki w celu otrzymania prawidłowych wyników badań DMA. Dla potwierdzenia wyników badań DMA jako materiał referencyjny przebadano PTFE (teflon) i porównano z wynikami literaturowymi.

The paper presents results of Dynamic Mechanical Analysis (DMA) of solid double-base rocket propellant. The authors investigated mechanical properties such as dynamic storage modulus (E'), dynamic loss modulus (E'') and tanδ (E''/E').Their temperature characteristics were measured with the use of Netzsch DMA 242C analyzer within temperature range from -120°C up to +90°C at 1K/min or 2K/min of heating rate, respectively. The sample was fixed in dual cantilever and subjected to 1Hz testing loads. Special attention was paid to the problem of proper selection of parameters of the analyzer as well as sample dimensions which were essential to obtain correct DMA results. To validate the results of DMA measurement polytetrafluoroethylene (PTFE) was tested as a reference material and compared with literature data.

Dynamic mechanical properties of parts from multicavity injection mould

75%

Bociąga E. , Jaruga T.

tom Vol. 23, nr 2

83-86

Purpose: The examination of dynamic mechanical properties of injection moulded parts, obtained from different cavities of injection mould, was the purpose of this research. The parts were manufactured from polypropylene. Design/methodology/approach: The testing method used was DMTA - "Dynamic Mechanical Thermal Analysis" - which is often used to determine the properties of polymers, blends and composites as well as the manufactured parts. Findings: The differences in storage modulus E' and loss factor tan delta of parts from particular mould cavities were found. The differences are caused by polymer flow and thermal conditions specific for each cavity. Research limitations/implications: An injection mould with geometrically balanced runners was used for investigation. The differences in parts' properties occur for every injection mould, but they are dependent on the cavities layout and runners configuration. Practical implications: The results of investigation provided the information that there are significant differences in parts' properties. Knowing that, the mould designers should take an effort to minimize the temperature differences in the mould and to assure the equal cavity filling. Originality/value: Usually the naturally balanced runners were supposed to assure the equal filling for all the cavities. Lately some research was made which discovered that this is not true. There were some solutions of this problem proposed. All investigation was focused on simultaneous plastic flow into all cavities, but there were no investigation of parts' properties.