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 the methods of uncertainty propagation have been extensively researched in the past three 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. This paper and its companion describe in detail the setup and results from two experimental studies that may be used for this purpose. The experimental work in this paper 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. One hundred 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 variability in the amplitude and phase of the measured frequency response functions is compared with numerical Monte Carlo simulation results. The data obtained in this experiments may be useful for the validation of uncertainty quantification and propagation methods in structural dynamics.
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| Amplitude across the frequency range | Amplitude in the Low-frequency range |
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| Amplitude in the Medium-frequency range | Amplitude in the High-frequency range |
