SUBSTRUCTURE-SUBDOMAIN METHODS FOR POWER FLOW ANALYSIS OF FLUID-STRUCTURE INTERACTION DYNAMICS

摘要

Based on a variational method adopting the dynamic pressure in the fluid or acoustic field and the acceleration of the solid as arguments in the functional, several substructure - subdomain methods are extended to power flow analysis of fluid - structure interaction systems. Formulations are presented of a displacement consistency model and a hybrid displacement model for the solid structure, a pressure equilibrium model for the fluid / acoustic field and a mixed substructure-subdomain model for the fluid-structure interaction system. The energy-flow density vector defining the energy transmission between one part of a material body / fluid field / system and another is expressed by mode vectors and the corresponding generalised coordinators of the substructures / subdomains. The local equation of energy-flow balance within a substructure / subdomain and the integral equation of energy-flow balance for a substructure / subdomain are presented. These substructure-subdomain methods make the application of a power flow analysis to structures, fluids and their interaction systems more effective and efficient especially in calculating solutions to large complex engineering problems. This is achieved through a suitable selection of mode vectors to reduce the number of degrees of freedom to a manageable size in a finite element method without reducing significantly the accuracy of solution of the original dynamics problem.