Nonlinear free vibrations analysis of cracked composite stiffened plates via X-Ritz approach

Risultato della ricerca: Conference contribution

Abstract

Thin and moderately thick composite multi-layered plates are widely employed in naval and aerospacestructures. They can experience the presence of cracks, generated for example by corrosion, fatigueor accidental external causes, which aect their static and dynamic behaviour. As regard the dynamiccharacteristics of plates, many studies have focused on the linear vibration analysis of both isotropicand composite thin and thick plates, providing for a comprehensive knowledge of the plate dynamicbehaviour. However, for an accurate appraisal of the plate dynamics, in some applications it is neededto investigate the nonlinear free vibration problem; a literature survey evidences that the large amplitudevibrations have received considerable attention for single plate congurations. Dierent approaches havebeen proposed to model cracked plates and, among others, the Ritz method shows adequate accuracyand computational eciency. To apply the Ritz method to crack problems by using standard admissiblefunctions the sub-structuring or multi-domain strategy has been employed. More recently, the Ritzapproach has been proposed with special trial functions, which account for the presence of the crack bydescribing the discontinuity of the solution across the crack and the tip singularity [1,2]. In the presentwork, nonlinear free vibrations of cracked stiened composite plates are investigated by modelling theproblem by the X-Ritz formulation recently presented by the authors [3]. In the framework of the rstorder shear deformation theory, this formulation combines the features of both the Ritz method and theX-FEM strategy, as it employs variables approximations obtained by enriching the Ritz series expansionwith suitably dened crack functions. This modelization applies to a single quadrangular plate and iscoupled with a multi-domain approach which open towards an ecient modelization of stiened panelsand thin-walled structures. Thus, the entire structure is modelled as individual, separated plates whichcan contain cracks; these plates are then joined by enforcing the continuity conditions along the commonedges through penalty techniques. This approach has: (i) the advantage of a very simple pre-processingstage, as it only requires the geometrical information on the plates that compose the structure and thecracks locations; (ii) the feature to incorporate the singular behaviour at the crack tips. Convergenceand accuracy studies on linear and nonlinear free vibrations of uncracked congurations are carried outon uncracked congurations to validate the approach by comparison with literature and nite elementsresults. Cracked stiened panels nonlinear free vibrations results are then presented to discuss thepotential of the method.References 1. Milazzo, A., Benedetti, I., Gulizzi, V. (2018). An extendedRitz formulation for buckling and post-buckling analysis of cracked multilayered plates. CompositeStructures, 201, 980-994. 2. Milazzo, A., Benedetti, I., Gulizzi, V. (2019). A single-domain Ritzapproach for buckling and post-buckling analysis of cracked plates. International Journal of Solids andStructures, 159, 221-231. 3. Gulizzi, V., Oliveri, V., Milazzo, A. (2019), Buckling and post-bucklinganalysis of cracked stiened panels via an X-Ritz method. Aerospace Science and Technology, in press
Lingua originaleEnglish
Titolo della pubblicazione ospiteMECHCOMP 2019 5th International Conference on Mechanics of Composites Book of Abstracts
Numero di pagine1
Stato di pubblicazionePublished - 2019

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