The present paper addresses comparison between predicted and measured bending stresses in one umbilical cross section during manufacturing. A factor with significant uncertainties has been which stresses that will occur during the manufacturing procedure when the umbilical is reeled on and off storage drums. The umbilical components may not only be exposed to pure elastic bending stresses due to the curvature radius but also second order axial stresses due to the combination of curvature gradients and finite length to the end fittings. In cooperation with Aker Kværner Subsea a.s., Marintek has developed a tool for stress analysis of Aker Kværner umbilical cross-section designs. The main motivation behind the development has been to reduce technical risk and costs associated with umbilical manufacturing, installation and operation. This is obtained by increasing the basic understanding of the umbilical cross-sections mechanical behaviour and the ability to quantify the stress response when exposed to various loads. In order to calibrate the mathematical model with regard to manufacturing stresses a 70 m long umbilical prototype was instrumented by strain gauges and reeled on an off a storage reel with radius 4.4 m. The paper presents the model applied to simulate this operation as well as the results from comparing predicted and measured stresses.

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