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Search: authors:"Łukasz Drąg"

3 papers found.
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Application of dynamic optimisation to stabilise bending moments and top tension forces in risers

The study discusses the problem of determining vertical displacements of a riser’s ends, which, despite its horizontal displacements induced by waves, mitigate stresses. A spatial model of riser dynamics is presented that considers the geometric nonlinearity due to large deflections. The Rigid Finite Element Method was used for riser discretisation. Analyses are reported that ...

Application of dynamic optimisation to the trajectory of a cable-suspended load

The paper discusses a dynamic model of the system consisting of an on-board hoisting winch on a moving vessel, cable, and load. The model accounting for large rope sag and hydrodynamic drag force was used to solve the problem of dynamic optimisation. The essence of which is what angle of rotation should be selected for the hoisting winch to ensure that the load during the defined ...

Compensation of top horizontal displacements of a riser

The nonlinear dynamic problem of catenary risers is solved by means of the rigid finite element method. The method enables us to model slender systems such as lines, cables and risers undergoing large base motions. The formulation allows elimination of large values of stiffness coefficients: shear, longitudinal and torsional (dependent on permissibility of the system analyzed). The ...