Finite element models of spot welds in structural dynamics: review and updating Matteo Palmonella a , Michael I. Friswell b, * , John E. Mottershead c , Arthur W. Lees a a School of Engineering, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, UK b Department of Aerospace Engineering, Queen’s Building, University Walk, University of Bristol, Bristol BS8 1TR, UK c Department of Engineering, University of Liverpool, Liverpool L69 3GH, UK Received 17 October 2003; accepted 7 November 2004 Available online 11 January 2005 Abstract Spot welds are used extensively in the automotive industry to join panels, and car bodies contain many thousands of spot welds. Different finite element models of spot welds have been created for various types of analysis. When struc- tures with many spot welds are analysed, these detailed models have too many degrees of freedom to be used in practice. Simple models that use few elements must be used instead. This paper reviews the spot weld models available in the literature. Model updating based on the measured vibration characteristics is then used to improve the accuracy of the most common coarse models of spot welds. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Spot welds; Finite element analysis; Structural dynamics; Model updating; Automotive structures 1. Introduction There are many models of spot welds used for static and dynamic structural analysis. Modelling spot welds is difficult, mainly because there are many local effects such as geometrical irregularities, residual stresses, material inhomogeneities and defects due to the welding process, that are not taken into account by finite element model- ling. Furthermore, models with a small number of de- grees of freedom must be used since real structures usually contain many spot welds and modelling each of them in detail would require a major computational effort. Two main types of spot weld models exist, namely those that require the stress within the weld spot to be calculated and those that do not. In the first case very detailed models are necessary to compute a smooth stress field at the spot weld. In the second case the only requirement from the model is to simulate, as closely as possible, the stiffness (and mass) characteristics of the real spot welds and their influence on the rest of the structure. This allows the use of much simpler models with far fewer degrees of freedom. A very detailed model produces a detailed and smooth stress field, but it will not necessarily accurately predict the stiffness of real spot welds and their effect on the rest of the structure. Detailed models will produce apparently reliable stress fields, whereas they may poorly estimate the forces that are interchanged between the 0045-7949/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.compstruc.2004.11.003 * Corresponding author. Fax: +44 117 927 2771. E-mail address: [email protected] (M.I. Friswell). Computers and Structures 83 (2005) 648–661 www.elsevier.com/locate/compstruc
Finite element models of spot welds in structural dynamics: review and updating
Jun 04, 2023
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