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Damage Assessment of Structures with Uncertainties Using Modal Interval Analysis(PDF)


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Damage Assessment of Structures with Uncertainties Using Modal Interval Analysis
FANG Sheng-en HUANG Ji-yuan ZHANG Bao
College of Civil Engineering, Fuzhou University
damage assessment uncertainty modal interval analysis interval expansion beam structures
In view of uncertain factors difficult to avoid in realworld engineering structures, such as inhomogeneous materials, unclear boundary conditions, testing and modeling errors, a method based on modal interval analysis was developed to solve the damage assessment problems of beams with uncertain parameters. Firstly, the calculation models of a steel box beam and a reinforced concrete beam were established in which the uncertainties of the geometric and material parameters were defined by intervals. The intervals reflected the possible fluctuation ranges of the parameters. Then the beam statics equations were extended to their interval forms, which were further interpreted and expressed by the modal logic. After that, the interval working states of the critical strain points of the beam were calculated under certain concentrated loads. In the analysis the damage was simulated by decreasing elastic modulus of the beam elements. The analysis results given by the deterministic method, the classical interval algorithm and the modal interval analysis were compared to find the difference. The results show that different to the deterministic method, interval analysis allows the involvement of uncertain parameters and the strains within the intervals are regarded as rational values. On the contrary, the strains beyond the interval envelope imply the damage occurrence of the beams under the specific loads. Meanwhile, the interval envelope given by the modal interval analysis is obviously smaller than that given by the classical interval algorithm, which means that the former can effectively avoid the interval expansion during the calculation process. Furthermore, the modal interval analysis can early detect the beam damage, as well as the corresponding external load, which can avoid the further deterioration of the damage.



Last Update: 2018-09-03