LAUSR

Dynamically embedded plate anchors (DEPLAs) are a relatively new anchor type that combine the advantages of dynamically installed anchors and conventional plate anchors. Through three dimensional finite element modelling, this paper first derives the combined loading yield surface of the anchor holding capacity in clay and then uses this yield surface in plasticity analyses to study the anchor trajectory under chain loading. These analyses reveal that the anchor padeye in the current DEPLA design is not optimally located as the anchor will eventually pull out of the seabed when loaded beyond its design capacity. It also shows that there are alternative padeye locations that lead to an equilibrium condition, where the DEPLA attains an ultimate holding capacity. The plasticity analyses are supplemented by simplified closed-form equations that are used in a parametric study to calculate the ultimate DEPLA holding capacity for various padeye positions. The optimal padeye location from the analyses is at a location that has a padeye offset ratio (ratio of the normal to the parallel distance between the padeye and the centre of rotation of the plate) in the range 0.55–0.65, varying slightly with chain loading angle.