In this thesis, the dynamic behavior and life estimation of conveying fluid pipes made of carbon nanotube reinforced composite materials have been studied. In this regard, the linear and nonlinear dynamic model of these pipes under the effect of fluid flow has been created, and by considering the pipe as a beam, the governing equations of motion of the system have been derived using Hamilton's principle for open systems. Since the ratio of the diameter to the length of the pipe is considered a relatively large value, shear deformation theories of beams have been used for dynamic modeling. Therefore, linear equations of motion have been derived using higher order shear deformation theory and nonlinear equations of motion have been derived using Timoshenko's beam theory. In the linear model, the assumption of inextensibility of the neutral axis of the beam has been applied where by this assumption, the number of motion equations has been reduced from three equations to two. In this case, it has been shown that for some specific values of the mass ratio, there are several values for the critical velocity, in which the pipe becomes unstable and then becomes stable in these regions with the increase of the fluid velocity. In the nonlinear model, assuming large deformations and applying von Karman's nonlinear geometric assumptions, nonlinear expressions are included in the equations of motion. By extracting the equations of motion of the pipe and applying the finite element method and the Newmark method, the equations of motion have been discretized in spatial dimension and time, respectively. Then by solving the resulting algebraic equations, the numerical results are presented in the form of figures and tables. In order to analyze the dynamic behavior of the system, the starting points of pipe instability specified as of Hopf bifurcation have been calculated and discussed. Also, the effect of fluid velocity and material properties of the pipe on the vibration behavior o