Investigating long‐term creep in a composite pipe subjected to transverse loading and aqueous condition

Abstract Glass‐fiber reinforced‐polymer (GFRP) pipes are widely used in various applications under wet conditions. Despite the considerable efforts on characterizing the mechanical response of GFRP pipes from various viewpoints in dry condition, less attention has been given to the influence of moisture absorption on their performance. The main goal of this research is to investigate the influence of moisture absorption on the long‐term creep behavior of GFRP pipes experimentally and theoretically. As experimental program, a GFRP pipe is subjected to a constant compressive transverse loading while it is submerged in water. Thus, the interaction between creep and water absorption are studied up to 5000 h. A systematic modeling procedure is also developed to evaluate the long‐term wet‐creep response of the GFRP pipes. Two scales of micro and macro are linked through an explicit modeling procedure. An excellent agreement is observed between experimental observations and outputs of the developed modeling procedure. Highlights A process is developed to model long‐term creep in composites under wet condition. Long‐term creep is predicted based on short‐term creep behavior of pure resin. Long‐term creep on immersed pipe in water under the transverse loading is simulated. Updating constitutive equations, nonlinear viscoelastic behavior is estimated. The effect of moisture absorption on the long‐term creep behavior is investigated.