Uncertainty in Structural Dynamics: Experimental Case Studies on Beams and Plates

Adhikari, S., Friswell, M. I. and Lonkar, K.
Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2007), Crete, Greece, June 2007.

The consideration of uncertainties in numerical models to obtain the probabilistic descriptions of vibration response is becoming more desirable for industrial scale finite element models. Broadly speaking, there are two aspects to this problem. The first is the quantification of parametric and non-parametric uncertainties associated with the model and the second is the propagation of uncertainties through the model. While methods of uncertainty propagation have been extensively researched in the past two decades (e.g., the stochastic finite element method), only relatively recently has quantification been considered seriously. This paper considers uncertainty quantification with the aim of gaining more insight into the nature of uncertainties in medium and high frequency vibration problems. Results from two experimental studies that may be used for this purpose are described in detail. The first experiment uses a fixed-fixed beam with 12 masses placed at random locations. The total `random mass' is about 2% of the total mass of the beam and this experiment simulates `random errors' in the mass matrix. The second experiment uses a cantilever plate with 10 randomly placed spring-mass oscillators. This experiment simulates the problem of `unmodelled dynamics', which in turn results in randomness in both the mass and stiffness matrices. For both experiments, 100 nominally identical dynamical systems are created and individually tested. The probabilistic characteristics of the frequency response functions are discussed in the low, medium and high frequency ranges. The data obtained in these experiments may be useful for the validation of uncertainty quantification and propagation methods in structural dynamics.
BiBTeX Entry
@INPROCEEDINGS{cp39,
    AUTHOR={S. Adhikari and M. I. Friswell and K. Lonkar},
    TITLE={Uncertainty in structural dynamics: Experimental case studies on beams and plates},
    BOOKTITLE={Proceedings of the Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN)},
    YEAR={2007},
    Address={Crete, Greece},
    Month={June},
    Note={}
}

by Sondipon Adhikari