DYNAMIC STABILITY AND TRANSIENT RESPONSE OF PIPE STRUCTURES CONVEYING FLUID FLOW USING FINITE ELEMENTS

A general finite element algorithm is developed to study the transient response and dynamic stability of three-dimensional pipe structures conveying fluid flows. The formulation fully takes into account the dynamic interactions between the structures and the flowing fluid. Transient solutions are obtained by employing a direct integration approach. Stability conditions are determined either by tracing the conventional Argand diagrams or, alternatively, by evaluating the attenuation behaviors of the transient responses. The structural impedance method, another numerical method, is reviewed and improvements of existing formulations are presented. The advantages and limitations of the numerical methods are discussed. Numerical examples of conservative and nonconservative systems are presented. The behaviors of straight pipes, curved pipes and combination of straight and curved pipes with in-plane and out-of-plane motions are presented and compared with analytical results and data from experimental work