Study Of Ship Damaged Stability Calculation Method

Based on the project named WARSHIP DAMAGED STABILITY RESEARCH AND REAL-TIME CALCULATION SOFTWARE DEVELOPMENT, sponsored by China Navy, this thesis studies typical methods of damaged stability calculation, and discuss the question of the compartment definition. This thesis puts forward a method to calculate the effect of the free surface to the great inclining angle stability at the greatest inclining moment, and calculates the damaged stability by using multi-SUMT.a) This thesis employs the simple boxes combination method, making full use of the ribs model data of the hull, getting the transverse section data of the compartment on every rib's position.b) A new method that uses the greatest inclining moment to calculate the free surface effect to the great angle stability in the paper. The method can reflect the effect of the liquid banks' shape, loading rates to the great angle inclining stability.c) This paper presents multi-SUMT to calculate the damaged stability of the ship in arbitrary inclining position in space. An optimization model with an objective function of the value of arm of stability and constraint of displacement equaling gravity and three variables of draft, heel angle and trim angle. Compared with traditional method by solving a Jacobi matrix, calculating account is greatly decreased because only displacement and center of buoyancy need computing while those elements of waterline plane are not required.d) Based on the research mentioned above, the paper presents the computer programmes of compartment definition, free surface effection, and some modules of the programme of the intact and damaged stability calculation. All the programmes have been tested by the real ships data.