Discrete Element Idealization of Fluids for Vibration Analysis

A new type of structural element for discrete element idealization of fluids is investigated. With this structural element and the standard structural elements, a missile and liquid propellant can be idealized as one composite structure consisting of many elements. A theory for taking slosh into account is derived by establishing a slosh stiffness matrix for the fluid elements. This development enables all linear displacement modes of a missile and liquid propellant to be computed. Some of the modes are zero frequency modes, reflecting a true liquid characteristic.