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Dynamic response of fully-clamped laminated plate subjected to small mass and low-velocity impact studied in this paper by using the suitable Algebraic Polynomials and Galerkin method. The first-order deformation theory as well as the displacement filed is used to solve the governing equations of the composite plate analytically. The interaction between the impactor and the target are considered in the impact analysis. This interaction is modeled with the help of a two degrees-of-freedom system, consisting of springs-masses. The results indicated that some of parameters like mass and velocity of the impactor in a constant impact energy level, mass of the plate (target), increasing the length-to-width ratio of the plate (a/b ratio) and orientation of composite fibers of plate are important factors affecting the impact process and the design of structures.

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The present research deals with the impact response of notched aluminum plates repaired by fiber metal laminate (FML) patches under various temperatures using drop weight impact test status. Some aluminum samples repaired by FML patches were prepaired to study their impact behavior and frcture mechanisms under drop weight tests at the temperature range of -20 ℃ to 60 ℃. An Energy Profiling Diagram (EPD) was used to obtain the penetration and perforation thresholds of hybrid composites. Besides, the effect of temperature on some impact characteristics such as endurance load, contact time and permanent deflection were also studied. The results showed that the amount of force for nearly all of the samples increased by increasing of the room temperature. The ability of energy absorption of the samples was also the most at the room temperature, therefore the energy thereshold of samples increases by increasing of the room temperature. Temperature variation also affects on the impact characteristics of composites patches and in some cases results in a 20 percent reduce in impact strength of the samples. It was also shown that the most value of impact parameters reaches at -20 ℃ and 60 ℃.

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Since aircrafts are subjected to aerodynamic and structural loads; one common defect in the aircraft fuselage and its wings is crack criterion. In most of the cases, the service life of defective parts can be increased by some sort of repairs. One of the most common types of repairs in this field is using composite patches and pasting them on damaged parts. These patches have significant advantages such as high strength, corrosion and moisture resistance, low weight and also excellent fatigue properties. In this study, base notched plates were fabricated by using of 2024 T4 aluminum alloy. Fiber metal laminate (FML) patches were made of carbon-epoxy and Phosphor – Bronze layers. These patches were attached to the base notched plate by using adhesive Arldit 2011. Specimens were subjected to tensile test and results of the tests were compared. The tested variables were chosen as lay-up, metal layer thickness and composite patch length. The results of current study indicate a dramatic increase in tensile strength of repaired parts by using these patches compared with the repaired notched parts without patches so that tensile strength is increased up to 82.4 % in the best sort of repair.

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In this study, the mechanical properties of PP/Graphene and PP/Talc/Graphene hybrid nanocomposites compared. All samples were prepared by melt mixing technique using an internal mixer. The coupling agent between filler and matrix was Maleic anhydride grafted polypropylene. For PP/Graphene binary nanocomposites, by adding 0.75wt. % Graphene, elastic modulus, tensile and impact strength were increased. In higher amounts of Graphene, modulus was increased while tensile and impact strength were decreased. For PP/Talc/Graphene hybrid nanocomposites, adding 15% wt. Talc to PP caused an increase in elastic modulus and a decrease in tensile and impact strength. Furthermore, after adding Graphene to PP/Talc, elastic modulus, tensile and impact strength were increased. In higher amounts of Graphene (0.75 to 1.5% wt.), tensile and impact strength were decreased. The morphology of the samples was characterized by using Scanning Electron Microscopy (SEM) technique and crystallinity behavior was characterized by Differential Scanning Calorimetry (DSC). The SEM micrographs shows that there is no good adhesion between talc and PP matrix. Also from SEM, in higher amounts of Graphene, its plates stack together. The DSC result shows that talc has no considerable effect and Graphene has negative effect on the crystallinity. The results showed that hybrid nanocomposites containing 15% wt. Talc and 1.5% wt. Graphene had highest elastic modulus while PP/Graphene nanocomposites containing 0.75% wt. Graphene had highest tensile and impact strength.

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Abstract- In this study, effect of adding graphene and poly olefin elastomer (POE) in polypropylene matrix, in various mix time were studied. Method of fabrication samples were melt-blending samples with 0, 2, and 4 %wt of graphene, 0, 15, and 30 %wt of POE and 8,12, and 16 minute mixing time were used. For a better analysis of mechanical properties, tensile and impact tests and DSC, SEM analyses were employed. Results of tensile tests indicated that adding of POE caused reduction of elastic modulus, reduction of tensile strength, good improvement of impact strength and poor improvement of elongation. While presence of graphene caused a good improvement of modulus, without meaningful effect on tensile strength, reduction of elongation and poor improvement of impact strength. DSC analysis of samples showed that graphene and POE has no visible effect on degree of crystallinity but graphen cause temperature of crystallinity increased. SEM observations showed that byincreasing of mixing time an improvehappens on dispersion of grapheme.A reduction in size of POE particles in blending of course agglomerations of grapheme in all samples were showed that for the method of fabrication , surface area of graphene and percents of graphene in samples was not unexpected.