In the past decade, Victaulic couplings have gained significant recognition as important piping elements, which are used mainly in water and slurry transportation systems. For example, grooved flexible Victaulic couplings offered significant economical and reliable piping connections when compared to other connecting elements such as flanges. Victaulic couplings are on average three times faster to install than welding piping connections. They are more reliable and cost-effective than flanges or threaded connectors. In addition, the speed and easiness of their assembly or disassembly as well as their flexibility and ability to provide thermal gaps make the couplings desirable as piping elements. Furthermore, the couplings provide stress designers with a rare opportunity to cheaply and reliably compensate for piping loads which are otherwise exerted on equipment attached to piping. For the above reasons Victaulic couplings are frequently used in current piping designs. In spite of their simple design and application they pose a significant challenge for stress designers. The stress software packages based on piping finite element theories which are commonly used in industry do not provide the means to model Victaulic couplings adequately. These packages are based on stress linear theories, and Victaulic couplings with their gaps are definitely non-linear elements. Therefore, the approach to model these elements is very approximate and is usually done by the use of nonlinear restraints built into the software. The stiffness and friction for Victaulic coupling “restraints” are rarely known and assumptions of their values have to be made in order to carry out calculations. Therefore, the prescribed values for the restraints directly influence the stress results. This work discusses assumptions based on several simple stress models. An attempt is made by the author to minimize conservatism as much as practical in the modelling of Victaulic couplings, while waiting for the manufacturers of these elements to test their products and provide meaningful statistical information, which could then be used to carry out stress predictions. The couplings’ stiffness, bending moment and axial force capabilities provided in this work must not be used for design purposes unless verified and accepted by the couplings’ manufacturers.

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