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In this paper, Taguchi statistical method is implemented in the design of energy-absorbing composite shell structures with cylindrical geometry. Six energy-absorbing structure design parameters considered in this study are: geometric parameters including internal diameter, length and thickness; the other parameters are the stacking sequence of layers, fiber reinforcement type and manufacturing process. The first three parameters and the remaining ones have four and two levels respectively. So the orthogonal array L16 (4 ** 3 2 ** 3) was used for analysis of Taguchi. The purpose of design of experiment in this study was to maximize the amount of specific energy absorbed in the structure. The result shows that the stacking sequence of layers and geometry parameter include internal diameter and thickness had an effect on the opposite side, the other parameters had Minimal effect on specific energy absorbing. The first three parameters had most important role in design of energy absorbing structures. Another important result of this analysis was to determine the optimal characteristics of composite energy absorbing shells with stacking sequence of layers (90/0), internal diameter 63 mm, thickness 2 mm, vacuum bag molding process (VB), the fiber reinforcement type carbon and the length 160 mm.

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In recent decades, new materials have had widespread applications in the construction industry. In the present research, a steel-FRP flooring system is proposed and tested. The implanted experiments are performed in two sections: at first, tests of constituent materials used in composite decks are done, and then full-scale tests of hybrid composite decks are performed. Mechanical tests, including three-point bending, compression, and tensile tests of GFRP profiles, tensile tests of steel plate, shear, and tensile tests of epoxy adhesives, are done with the aim of reaching mechanical properties. Next, flexural tests on four decks are performed. The main variables considered are the length of composite decks, the cold-formed steel channel effect, and the number of GFRP profiles. In examining the composite decks, the fracture between cohesive layers was observed, and damage localization and fracture in profiles occurred. It found that the use of the steel plate increases the stiffness and load-bearing capacity of the decks. The primary failure mode in the experimental work was deboning between profiles and adhesive fracturing in the decks without steel plates. In the decks which are used steel channels, the complete composite action of the structure was observed, resulting in suppressing the debonding phenomenon. The decks with cold-formed steel channels exhibit higher reliability as a result of their ductile behavior. After the tests of composite decks, the composite decks were modeled in the Abaqus software, and the results of the experiments and simulations were compared together. The results of numerical analysis have good agreement with experimental data.