The analysis was done on behalf of BMH Marine AB. The construction under study, is a ship un-loader with transport-arms hoisted by wires. The target issue for the analysis is the shock loads of the structure in an event where the outer (near to the ship) transport-arm gets hooked by an obstacle, such that a considerable slack of the wires result, and is suddenly released from the obstacle now falling under gravity loading until the wires are streched. The simulation covers the initial 2 second and the simualtion tool used was LS-DYNA.

The model is built by shell and beam elements. The model entails such details as a proper consideration of the wires rolling on/off the reels, from the rear, with the hoisting motor, over the top reel, and a multiple loops around the forward low reel and top reel.

The figures show: the initial state where the feeder-arm has been hooked up, the state of deformation after 1.1 seconds (the forward packet of wires has reached its upper swing end in its "lash"), resulting buckles, due to plastic deformation, at time 2.4 seconds.

Keywords: BMH Marine AB, FE analysis, LS-DYNA, MEDINA, transient dynamic, elasto plastic, buckling analysis