Papers by Keyword: Thermal and Mechanical Properties

Abstract: This paper focuses on both thermal and mechanical properties of the composite pastes. Heat-treatment was carried out at temperatures up to 105 and 900 °C for 6h, respectively. Thermal conductivity of the specimens enriched with 3 wt% nanoSiO₂ was approximately 60% higher than that of pure paste. Volume heat capacity of the composite pastes displayed 28% increase. Moreover, the composite pastes contributed to ~25% improvement of compressive strength. XRD, and TG-DSC were employed to investigate the cause of physical and thermal changes in the heated specimens.

Abstract: A low expense chloro-monomer, 1-(4'-chloro-1-benzoyl)-3-(4'-1-choro-benzene sulfonyl)-benzene(CBCBSB), was synthesized by the Friedel-Crafts reaction of m-chlorosu1fonyl benzoyl chloride with chlorobenzene. A novel poly (aryl ether sulfone ketone)s (PAESK) containing m-sulfonylbenzoyl linkages in the main chains were prepared by copolycondensation of CBCBSB with hydroquinone in N, N-Dimethylacetamide (DMAc). The structure of PAESK was confirmed by FT-IR, 1H-NMR and characterized by XRD. thermogravimetry (TG) and Differential Scanning Calorimeter (DSC) were carried out to demonstrate its good melt processability. The polymer exhibited the better solubility in chloroform, N-methyl-2-pyrrlidone(NMP), dimethylacetamide(DMAC), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) and excellent mechanical performance.

Abstract: In this paper the behavior of hexagonal honeycombs under dynamic in-plane loading is described. Additionally, the presence and influence of the filler gas inside the honeycomb cells is considered. Such structures are subjected to very large deformation during an impact, where the filler gas might strongly affect their behavior and the capability of deformational energy absorption, especially at very low relative densities. The purpose of this research was therefore to evaluate the influence of filler gas on the macroscopic cellular structure behavior under dynamic uniaxial loading conditions by means of computational simulations. The LS-DYNA code has been used for this purpose, where a fully coupled interaction between the honeycomb structure and the filler gas was simulated. Different relative densities, initial pore pressures and strain rates have been considered. The computational results clearly show the influence of the filler gas on the macroscopic behavior of analyzed honeycomb structures. Because of very large deformation of the cellular structure, the gas inside the cells is also enormously compressed which results in very high gas temperatures and contributes to increased crash energy absorption capability. The evaluated results are valuable for further research considering also the heat transfer in honeycomb structures and for investigations of variation of the base material mechanical properties due to increased gas temperatures under impact loading conditions.