MECHANICAL STRESSES IN MARITIME （机械应力在海上）.pdfVIP

MECHANICAL STRESSES IN MARITIME TRANSPORT Section 1 General conditions in the CTU packing guidelines clearly states, for example in point 1.1: Voyages are made in a variety of weather conditions which are likely to exert a combination of forces upon the ship and its cargo over a prolonged period. Such forces may arise from pitching, rolling, heaving, surging, yawing or swaying or a combination of any two or more. Point 1.2 continues: Packing and securing of cargo into/onto a CTU should be carried out with this in mind. It should never be assumed that the weather will be calm and the sea smooth or that securing methods used for land transport will always be adequate at sea. The acceleration values to be anticipated in maritime transport depend on the shape of the surface or sub- surface vessel, its beam, the position of the center of gravity and center of buoyancy and similar parameters which determine the behavior of ships at sea Ship movement at sea SUMMARY OF SHIP MOVEMENT All kinds of ship movement may be divided into three types of linear motion and three types of rotational motion. Linear motion Rotational motion Surging is motion along the longitudinal axis. Rolling is motion around the longitudinal axis. Swaying is motion along the transverse axis. Pitching is motion around the transverse axis. Heaving is motion along the vertical axis. Yawing is motion around the vertical axis. It can in general be stated that the outwardly directed centrifugal