Surrogate Based Optimization Of Resistance Reduction Of The Amphibious Vehicle

With the fast development of science and technology applied in the defensesector, owning the high performance amphibious vehicle has important strategicsignificance for the country with vast land, many coastal countries, and complexgeographical environment. In order to improve the operational performance of theamphibious vehicle, sailing speed must be increased. As one of the most importantmeans to increase sailing speed, optimization on shape is of great value. In this paper,optimization of resistance reduction is mainly carried on based on CFD and Surrogatemodel. The main contents and results are as follows:A more applicable method of numerical research of amphibious vehicle isadopted. Contrast to the traditional method, the ways to getting unstructured grid, toadjusting the position and angle of the vehicle are changed, besides a properiateadjustment strategy in numerical calculation is presented. Compared the CFD resultswith the experiment results, they are in high similarity which means the CFD methodis highly reliable.A method of optimization of resistance reduction based on Surrogate model isadopted. The steps of the optimization, a detailed explanation of the each step, and theMATLAB programme are all shown in the method. Considering the particularity ofthe method and the amphibious vehicle issues, common optimization of the vehicleare divided into six types.The optimal solution of the sailing tilt of the amphibious vehicle is obtained byusing the optimization method. And it is as an example of the problems with oneindependent varialbe and one target variable. The result shows that the sailing tilt ofthe amphibious vehicle has a perfect solution, and the resistance increases if givenanother sailing tilts.The optimal solution of the aspect ratio of the amphibious vehicle is obtained byusing the optimization method. And it is as an example of the problems with oneindependent varialbe and two or more variables. The result shows that the resistance decreases with the increase of the aspect ratio, but at the expense of stablity of thevehicle, and therefore the aspect ratio of the amphibious vehicle do have an optimalsolution.The optimal solution of the angle of the empennage, the angle breakwater, andthe center of the gravity of the amphibious vehicle is obtained by using theoptimization method. And it is as an example of the problems with two or moreindependent varialbes and two or more target variables. The result shows that thesensitivity of the resistance to the three factors varies with the sailing speed. Since theoptimal solution at each speed is different, the optimal solution at all speed is at theexpense of all the single resistance at each speed.