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Effect of Modified Carbon Nanotubes Epoxy on the Mechanical Properties of Concrete Reinforced with FRP Sheets

Kazemi Hamid, Heydari Mostafa, Bamoharam Fateme Farash

Civil and Environmental Engineering Reports

2021

Vol. 31, no. 3

177--196

Today, using Fiber Reinforced Polymer (FRP) sheets is one of the conventional methods in retrofitting concrete structures. Some factors affecting FRP sheets proper performance include mechanical properties, surface specifications, connector’s material and connecting approach in concrete elements. Previous studies showed that FRP epoxy resin and its basic surface have a significant impact on the ultimate bearing capacity. In line with the development of nanotechnology in recent years, this paper presents an experimental study to show the effects of adding the best percentage of nano-carbons to adhesive resin and evaluate the ultimate axial, shear and bending strengths in concrete samples. The results show that using FRP with carbon nanotube reinforced resins will significantly increase stiffness and ductility by 100%; moreover, it shows an effective increase of almost 13% in axial and flexural strengths of specimens.

The hydrodynamic resistance of stepped planing hulls under different geometrical and physical conditions

Najafi Amin, Nowruzi Hashem, Salari Mahmoud, Kazemi Hamid

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2019

nr 58 (130)

24--31

In this paper, the hydrodynamic resistance of one-step planing craft has been experimentally investigated under different geometrical and physical conditions. For this to be accomplished, a Fridsma body model with different deadrise angles was considered. Moreover, the effect of the longitudinal distance of the step from the transom and the step height on the hydrodynamic resistance of a stepped planing craft has been evaluated at different hull velocities. According to the experimental results, frictional resistance can be enhanced by decreasing the height of the step. However, a greater total resistance can be obtained by increasing the longitudinal distance of the step from the transom. Moreover, it was found that the proportionality of the longitudinal distance of the step from the transom to the step height has a remarkable effect on the hydrodynamic efficiency of the step in stepped planing craft.