Research on mechanical model for the J-lay method

The J-lay method is regarded as the most feasible way to lay pipeline in ultra-deep water; however, the time required to compute the forces generated is considerable. In this article, a new and simple mechanical model is developed in order to reduce the calculation time required. It comprises two parts: the first is a pipe-soil interaction model based on the linear beam theory and the Winkler foundation model, and the second is a nonlinear, large deflection beam theory to calculate the forces on the suspended segment. The accuracy of the numerical calculations has been verified against the output of commercial software with good results. Furthermore, high-order shear effect, which has been largely ignored in other publications, is discussed. The results show that computational accuracy can be improved by 3.1% by taking this effect into account. Therefore, the mechanical model proposed in this article is quicker and more accurate for determining the forces encountered during J-lay operations.