Flexible Pipe Anchoring System: Resin Ratio Effects on Mechanical Properties

At the end of flexible pipe manufacturing, the assembly of end fittings ancillaries is necessary to provide the connection with the platform and the subsea systems. The assembly process uses epoxy resin to ensure the holding of the tensile armor layers inside the end fitting. The anchoring system has great importance in the integrity of the flexible pipes system, since their failure causes the separation between the flexible pipe and ancillaries, what can put on risk the production and the environment. During the qualification tests of new structures were observed that some variables of the process could be determinant on the mechanical strength resistance required for the product. One of these known variables is the ratio resin/hardener. Resin supplier specifies at the datasheet the proper ratio to obtain the full cure, but it was observed that small variations in the concentration alters the maximum tensile anchoring strength supported by the structure, as well the minimum curing time that should be obeyed, so it can be better used regarding their mechanical properties. In this way, laboratorial tests were conducted to enhance the performance of this resin in the tensile anchoring system, according to Prysmian Surflex products’ necessity. Compression tests varying the resin/hardener ratio were done to evaluate the resistance as a function of curing time. Besides this, tensile tests (tensile wire pulls over from resin) were conducted to establish a relation between maximum tensile load and the resin ratio, and so provide enough data to control the best proportion of resin during the end fitting assembly phase.