Seismic response of underwater fluid-conveying concrete pipes reinforced with SiO2 nanoparticles and fiber reinforced polymer (FRP) layer

This study aims at investigating the seismic response of the fluid-conveying concrete pipes reinforced with SiO2 nanoparticles and fiber reinforced polymer (FRP) layer. The earthquake acceleration is consistent with the earthquake occurred in Tabas. It is assumed that the structure is subjected to external forces which exerted by inner and outer fluids. The force due to the inner fluid is evaluated using Navier-Stokes equation. Also, Mori Tanaka model is employed to take into account the agglomeration effect of SiO2 nanoparticles. The mathematical model of the structure is developed based on the first order shear deformation theory (FSDT) and the governing equations are derived using energy method and Hamilton's principle. Finally, the problem is solved employing differential quadrature method (DQM) and Newmark method and the effect of different parameters like SiO2 nanoparticles agglomeration and volume percent, inner and outer fluids, various boundary conditions and geometric parameters on the dynamic deflection of the structure is studied. The results indicate that with increasing the thickness to radius ratio and volume fraction of SiO2 nanoparticles and also employing the NFRP layer, the dynamic deflection of the structure decreases while considering the effect of inner and outer fluids and agglomeration of SiO2 nanoparticles and increasing the length to thickness ratio increases the dynamic deflection of the structure.