Reliable onboard stability assessment for a damaged ship is of great importance to ship operators. This paper presents a practical method to calculate ship's damage stability directly from the full three-dimensional (3D) geometric models, in which the method of lost buoyancy is used. First, the computational database is established by cutting the 3D models of hull and compartments in transverse direction according to ship's frame distance table; Then, trapezoidal rule integration method is adopted to calculate ship's volumetric data; After that, the centre of gravity of liquid loads is calculated using Newton's iterative method; Finally, ship's equilibrium state of balanced trim and draft for a given heel angle is determined using a successive linear method, and the right level could be obtained. Lloyd's Register (LR) test cases for IACS UR L5 Type 1, 2 and 3 are used to verify the proposed method. In every stage of the test program, the method achieves a high-accuracy result, and thus can be used onboard to calculate intact stability and damage stability of ships by direct application of preprogrammed damage cases, especially for bulk carriers and tankers.

对受损船舶进行可靠的船上稳定性评估对船舶经营者至关重要。本文提出了一种实用的方法，可以直接从完整的三维（3D）几何模型中计算船舶的破坏稳定性，其中使用了失去浮力的方法。首先，根据船架距离表，通过横向剖切船体和舱室的3D模型，建立计算数据库。然后，采用梯形规则积分法计算船舶的体积数据。之后，使用牛顿迭代法计算液体载荷的重心；最后，使用连续线性方法确定给定倾角时船体平衡的吃水和吃水深度的平衡状态，可以获得正确的水平。劳埃德 ■使用IACS UR L5类型1、2和3的寄存器（LR）测试用例来验证所提出的方法。在测试程序的每个阶段，该方法均能获得高精度的结果，因此可通过直接应用预编程的损坏案例（特别是散货船和油轮）在船上用于计算船舶的完整稳定性和损坏稳定性。