Random eigenvalue problems in structural dynamics: An experimental investigation

Adhikari, S., Phani, A. S. and Pape, D. A.
50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics & Materials Conference, Palm Springs, California, USA, May 2009.

An experimental investigation of uncertainty in natural frequencies of linear structures estimated from measured frequency response function (FRF) under dynamic loading is presented. Experiments were conducted on one hundred nominally identical realizations of a fixed-fixed beam; each realisation was obtained by placing twelve identical masses at random spatial locations (generated by a computer) along the length of the beam. The total ‘random mass’ is about 2% of the total mass of the beam. These experiments represent parametric uncertainty in the mass matrix, and hence may be useful for the validation of many random eigenvalue analysis and prediction methods currently available to structural dynamicist. Predictions from Monte Carlo simulation of deterministic finite elements model are compared with experiments. It is concluded that the method of estimation of natural frequencies from FRFs and the spatial location of the measurements has significant influence upon the first two moments (mean and standard deviation) of the natural frequency ensemble. Furthermore, whilst the Monte Carlo simulation estimates of the mean and standard deviation are in reasonable agreement with experiments at higher frequencies, the probability density function differ appreciably, within the limits of the sample size investigated in this study.
BiBTeX Entry
@INPROCEEDINGS{cp63,
    AUTHOR={S. Adhikari and A. Srikanth Phani and D. A. Pape},
    TITLE={Random eigenvalue problems in structural dynamics: An experimental investigation},
    BOOKTITLE={Proceedings of the 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics \& Materials Conference},
    YEAR={2009},
    Address={Palm Springs, California, USA},
    Month={May}
}
by Sondipon Adhikari