The Holtrop & Mennen method is widely used at the initial design stage of ships for estimating the resistance of the ship (Holtrop and Mennen, 1982). The Holtrop & Mennen method provide a prediction of the total resistance’s components. In this work we present a neural network model which performs the same task as the Holtrop & Mennem’s method, for two of the total resistance’s components. A multilayer perceptron has been therefore trained to learn the relationship between the input (length-displacement ratio, prismatic coefficient, longitudinal position of the centre of buoyancy, after body form and Froude number) and the target variables (form factor and wave-making and wave-breaking resistance per unit weight of displacement). The network architecture with best generalization properties was obtained through an exhaustive validation analysis (Bishop, 1995). The results of this model have been compared against those provided by the Holtrop & Mennen method, and it was found that the quality of the prediction is improved over the entire range of data. The neural network provides an accurate estimation of two total resistance’s components with Froude number and hull geometry coefficients as variables.
Ortigosa Barragán, Inmaculada; Garcia Espinosa, Julio International Conference on Computational Methods in Marine Engineering p. 129-132 Presentation's date: 2009-06-18 Presentation of work at congresses
The model presented in this paper is part of the development and integration of a System to Support Decision (SAD) for assistance in the design and actuation of sails. The model is based on the union of a wireless sensor system, continuously connected to a calculation/simulation system. This system will predict the structural behavior and
performance of the different configurations of the rigging of a sailing ship.
The simulation software will be communicated in real time with wireless sensors and
interfaces through suitable filters. The information gathered by the sensors, which are integrated into the structure of the boat, will be used in numerical algorithms to determine the efforts that are suffering the Structure and evaluate the overall performance of the sailboat.
The system of calculation / simulation is made up of a model of structural calculation based on a quasi-static method with a formulation for large displacement typical of the finite element method, and includes models of membranes, cables and bars. And the starting point of the simulation tool of fluid dynamics is the method of vortices (contour elements). The algorithms are adapted so that they can make real-time data that offers the monitoring system. The software also has algorithms simulation maneuver with which you can change the
position of the sails.
Ortigosa Barragán, Inmaculada; López González, Roberto; Garcia Espinosa, Julio International Congress on Maritime Technological Innovations and Research p. 211-220 Presentation's date: 2007-11-22 Presentation of work at congresses
Ortigosa Barragán, Inmaculada; Garcia Espinosa, Julio II International Conference on Computational Methods in Marine Engineering (MARINE 2007) p. 223-226 Presentation's date: 2007-06 Presentation of work at congresses