Estudo do comportamento mecânico de uniões de tubulações de FRP sujeitas ao golpe de aríete

Abstract

Fiber Reinforced Polymer pipes, or simply FRP pipes, have an excellent strength to weight ratio. They are commonly installed in corrosive environments for fluid transportation such as produced water, potable water, salt water, chemical products and low pressure firefighting lines. Fabrication of this kind of piping is very diversified and demands a series of bonding and lamination techniques combining polymeric resins, fiberglass or carbon fiber. Being a relatively recent technology, still establishing itself on the market, technical information is scarce when compared to more traditional materials. Therefore new procedures and methodologies are needed to aid research and characterization of such lines. In every process plant and hydraulics system occurs an undesirable effect called water hammer (WH). WH occurs when there is a rapid variation of the flow rate, due to the closing of a valve or start of a pump, causing pressure variation. This work is not aimed at investigating the maximum pressure, but rather to analyze FRP piping when submitted to WH and its behavior during failure. Test conditions were, piping with 10 in diameter and maximum working pressure of 20 bar. The water hammer occurred at an interval between 1 and 2 seconds, in which the pressure was up to 5x higher than the maximum working pressure. To accomplish this a partnership between Laboratory of Adhesion and Adherence and a private company was established to develop the equipment fit to purpose. Various failure modes could be observed during testing, from small debonding and points of weepage, to complete shearing of the joints. Failure analysis is of key importance to the integrity of the system, helping prevent from small leaks to damage to equipment, property and occupational hazards.