Experimental identification of a stochastic computational dynamical model using modal data measured for a family of built-up structures

Anas Batou (1) , Christian Soize (1) , S. Audebert (2)

1 MSME - Laboratoire de Modélisation et Simulation Multi Echelle
2 EDF R&D AMA - Analyses Mécaniques et Acoustiques

This research is focused on the construction and the identification of a stochastic computational model (SCM), using experimental eigenfrequencies and mode shapes measured for a family of real structures exhibiting slight differences that induce variability in the measured quantities. The statistical properties of the SCM are controlled by a set of hyperparameters such as mean values, coefficients of variation, etc. The hyperparameters are identified using the first experimental natural frequencies, and the associated experimental mass-normalized mode shapes measured for the family of real structures. The methodology proposed introduces a random transformation of the computational modal quantities (computational eigenfrequencies and computational mode shapes) in order to make them almost surely in correspondence with the experimental modal data of each measured real structure. Thus this methodology automatically takes into account the mode crossings and mode veerings which can take place between the experimental configurations and the computational realizations of the SCM. Then the hyperparameters are identified using the maximum likelihood method. The proposed methodology is applied to a booster pump of thermal units for which experimental modal data have been measured on several sites.

Mots clés: Structural dynamics; Model identification; Computational stochastic dynamics; Mode crossing; Experimental modal analysis; Uncertainty Quantification

Domaines: Mécanique [physics.med-ph]; Probabilités [math.PR]; Statistiques [math.ST]

Anas Batou, Christian Soize, S. Audebert. Experimental identification of a stochastic computational dynamical model using modal data measured for a family of built-up structures. IMAC Conference & Exposition on Structural Dynamics (IMAC 2015), Feb 2015, Orlando, Florida, United States. pp.1-8. ⟨hal-01158275⟩