Mixed finite element method and applications to dynamic analysis of fluid-structure interaction systems subject to earthquake, explosion and impact loads

A mixed finite element method and corresponding computer code for dynamic analysis of fluid structure interaction systems subject to earthquake excitations, explosion waves and impact loads are presented. A variational principle is formulated to describe interaction dynamics and a mixed displacement-pressure finite element model is derived. To improve numerical efficiency, a substructure-subdomain technique is adopted. Three examples are presented to provide some engineering applications of the developed method and computer code. Example 1 concerns a LNG tank-water interaction system subject to an explosion pressure wave. Example 2 investigates the dynamics of a building structure-acoustic volume system subject to human footfall impacts. Example 3 studies a liquid storage tank excited by earthquake loads. Natural vibrations and dynamic responses of three examples are obtained and discussed for the designs of engineering products involving fluid-structure interactions.