Development of a Multifactor Regression Model of Ship Maneuvering Forces Based on Optimized Captive-Model Tests

The paper provides the results of model tests planned with an optimized experimental design method. Captive-model tests have been carried out according to such a design on a computerized planar-motion carriage with a model of a fast catamaran with five varying factors (drift angle, rate-of-yaw amplitude, sinkage, trim and heel angles) and with all six force/moment components measured at each run. The measured values were used after preprocessing for construction of polynomial regression models for all force components acting upon the catamaran's hulls. It is demonstrated that the optimized experimental design method allows rather complicated mathematical models for maneuvering hydrodynamics forces to be obtained from captive model tests at a reasonable level of effort.</jats:p

An Algorithm for Optimized Design of Maneuvering Experiments

Properties of an adjusted version of Mitchell's algorithm for synthesis of D-optimized experimental designs for response estimation were studied numerically for a third-order polynomial linear regression model widely used in ship maneuvering. Numerical experiments for 2, 3, and 4-factor cases were conducted for different numbers of levels in the classic full-factorial plan used as a set of candidate points. Selection of the runs to be included in the design under construction was made after an exhaustive search. Initial designs were obtained with the pseudo-random or quasi-random generation. A method of assembling an optimized design with the given degree of redundancy is proposed. An important conclusion is that relatively coarse grids can be used for discretizing the factor space that can facilitate substantially the synthesis of the designs without any significant loss of quality.</jats:p