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Title: On the dynamic analysis of engineering structures with high and low level random uncertainties
Author: Cheepsomsong, Thana
ISNI:       0000 0004 5348 0239
Awarding Body: University of Sussex
Current Institution: University of Sussex
Date of Award: 2014
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The ability to predict the effect of dimension and thickness variability on the dynamic response of realistically uncertain engineering structures is examined in this thesis. Initially, available methods for predicting key response statistics and probabilities, for both low and high frequencies are examined to establish their strengths and limitations for specified levels of random dimension variability. For low frequency applications, the ability of Direct Integration (DI) and the First-Order Reliability Method (FORM) to predict exceedance probability is examined. For high frequency applications, the ability of the methods of Statistical Energy Analysis (SEA) and DI to predict the mean and standard deviation of the energy response is examined. The use of Extreme Value (EV) theory is included as a way to bound responses using simulated or measured responses. The strengths and limitations of Monte Carlo simulation methods are explored for both low and high frequency responses of randomly uncertain structures using both simple mode superposition plate-structure solutions and (commercially available) finite element solutions for coupled plate structures. To address, without the need to undertake expensive Monte Carlo simulation, the problem of predicting response bounds for structures with varying levels of uncertainty, a novel DI-EV method is developed and examined. It is tested first on a simple plate structure, then on a coupled plate structure, with low-level and high-level random dimension and thickness uncertainty. In addition, the method is compared with the SEA-EV method. The thesis shows that the results from the existing SEA-EV bounding approach gives good bounds only at particular frequencies and mainly for low levels of dimension variability. In contrast, the proposed DI-EV bounding approach compare extremely well with Monte Carlo simulations, which is not only at all frequencies but also with both low-level and high-level uncertainties, for simple and coupled plate structures with dimension and thickness variation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA0630 Structural engineering (General)