Finite element model updating using in-situ experimental data

Meggitt, JWR; Moorhouse, AT

Abstract

Conventional model updating methods are based on frequency response functions (FRFs) and/or modal parameters
estimates obtained from freely suspended, or sometimes rigidly constrained, sub-structures. These idealised boundary
conditions are however often difficult to realise in a practical scenario. Furthermore, they are in conflict with the requirement that the sub-structure should also be measured whilst under a representative mounting condition. This paper
addresses the question whether model updating can be achieved in the presence of an arbitrary or unknown boundary
condition using in-situ measurements, i.e. without removing the sub-structure from its assembly. It is shown that
some measurable properties, dynamic transfer stiffness and generalised transmissibility, are invariant to sub-structural
boundary conditions and can therefore be obtained in-situ. It is further shown that, with minor adaption, existing
transmissibility-based updating methods can be applied more widely than previously thought; to sub-structures whose
boundary conditions are non-ideal. The theory is verified by a numerical beam example. Application to a resilient
isolator is then demonstrated where a finite element model is successfully updated without removing the isolator from
its assembly.

• Journal Article Type: Article
• Acceptance Date: Aug 27, 2020
• Online Publication Date: Sep 1, 2020
• Publication Date: Dec 22, 2020
• Deposit Date: Aug 27, 2020
• Publicly Available Date: Oct 2, 2020
• Journal: Journal of Sound and Vibration
• Print ISSN: 0022-460X
• Publisher: Elsevier
• Volume: 489
• Pages: 115675
• DOI: https://doi.org/10.1016/j.jsv.2020.115675
• Publisher URL: https://doi.org/10.1016/j.jsv.2020.115675
• Related Public URLs: http://www.journals.elsevier.com/journal-of-sound-and-vibration/