The Application of FEM-BEM Approach to Simultaneous Dynamic Analysis of Several Thin-walled Fuel Tanks

At research of dynamics of longitudinal movement of the flying device with big weights of fuel the problem about fluctuations of thin-walled fuel tanks preliminary is solved. In such problems has well proved a method of finite and boundary elements. This approach allows to lead direct calculation of a sheaf of tanks, that considerably facilitates procedure of construction of mechanical analogue. Dynamic pressure of a liquid upon stacks of a tank within the limits of a direct method of boundary elements is expressed through moving shells and the mass and rigidity matrix of the attached weights of a liquid which joins in the settlement scheme together with matrixes of weights and a tank, received as a result of digitization of a design of a tank on FEM is calculated. After the decision of the generalized problem of own values for the received matrixes integrated characteristics of fluctuations which can be used at construction of mechanical or "matrix" analogue of a tank for the decision of the general problems of flying device dynamics can be found. The way of the description of geometry of a tank on the basis of natural approximation of a curve is offered.