Effects of extensible modelling on composite riser mechanical responses

The change from steel risers to composites comes with uncertainties that led large safety factors. One area of uncertainty is the predicted response and stresses derived commercial packages are based on formulations assume in-extensible riser. However, composite pipes exhibit a lower axial stiffness therefore velocity waves will corresponding in dynamic response. To determine effect this assumption, paper assesses extensibility time-domain It found model predicts 3 times number high frequency tension cycles 20 kN range. impact stress, accuracy available pipe models benchmarked using shell, continuum-shell solid elements. quadratic elements provide maximum percentage difference 4% compared but selected as it has computational cost. extensible input into model, they similar Tsai-Wu failure factors, alleviating concerns when modelling strength. dynamics remains concern for other applications such machine-learning or digital-twins.