Identification of design parameter variability of honeycomb sandwich beams from a study of limited available experimental dynamic structural response data
The goal of this paper is to characterise the variability of two important design parameters of thermoplastic honeycomb sandwich beams from the analysis of experimentally determined resonance frequencies and mode shapes of a limited number of test beams, under free boundary conditions. The design parameters are the Youngs modulus of the skin in length direction of the beam and the out-of-plane shear modulus of the honeycomb core. These two independent parameters are expressed as random fields using a KarhunenLove series expansion of the covariance matrix, available after updating the finite element models using the experimental vibration data. The random variables of this series expansion are expressed in terms of a Hermite polynomial chaos. The aleatory uncertainty is modelled by the Gaussian random variables while the epistemic uncertainty is described by the randomness of the polynomial chaos coefficients. An estimation of the uncertainty resulting from the experimental and numerical modal analysis is discussed, along with its influence on the two considered stiffness parameters.
pc polynomial chaos kl karhoenenlove fem finite element modelling fea finite element analysis ema experimental modal analysis rf random field pdf probability density function frf frequency response function fft fast fourier transform mc monte carlo mcmc monte carlo markov chain bi bayesian inference svs shell volume shell mac modal assurance criterion ci confidence interval cov coefficient of variation