A Specialised Element for Finite Element Model Updating of Moveable Joints

Multibody system dynamics is a vast area of study that mayoften involve the need to know the vibration behaviour of rigid/flexiblesystems with configurations that change with time due to the existenceof moveable joints. This paper introduces and discusses the motivationbehind the development of a technique, based on a modified springelement, to model the dynamic behaviour of such moveable joints. Thistype of joint generally connects the constituent components ofmechanical systems. The modified element is used to establish linksbetween nodes inside the joint volume, for an arbitrary jointconfiguration, without the need to introduce any distortions in thefinite element mesh pertaining to the connected components. Itintroduces two parameters ideally suited for model updating, a geometryindependent parameter that defines global link stiffness and a geometrydependent one that gives a measure of link effectiveness as a functionof joint configuration. The element usage and a comparison of resultsobtained with a model using standard elements for selectedconfigurations are illustrated by means of an example.