Variation of structural vibration characteristics versus non-uniform temperature distribution

Abstract

In vibration-based condition assessment exercises, it is necessary to discriminate the variation of structural properties due to environmental changes from those caused by structural damage. Some efforts have been made to correlate the structural vibration characteristics and the air temperature or temperatures at the structural surface. As the temperature of an entire structure is generally non-uniformly distributed, using the air temperature or surface temperatures alone may not sufficiently capture the relation between the structural responses and temperatures. The present paper aims to investigate the variation of the structural vibration characteristics versus the non-uniform temperature field of the structure. Thermodynamic models are employed to estimate the temperature at different components of the structure at different time.As the material mechanical properties are temperature dependent, the structure can be regarded as a composite structure consisting of elements with different Young's moduli.Consequently the natural frequencies of the structure can be calculated with the finite

Long-Term Vibration Monitoring of the Effects of Temperature and Humidity on PC Girders with and without Fly Ash considering ASR Deterioration

“…The results of the torsional modes were not shown because they were not identified with sufficient precision to detect the environmental effects. These obstacles were reported in other studies as well [8,15,19]. The results of the extensive validations show that the correlation between the variations in the natural frequencies and the temperature-induced changes in Young's modulus could be proved reasonably using the FE model developed in this study.…”

“…Thus, the fly ash significantly affected the vibration properties of the PC girders subjected to the ASR-induced deteriorations. Because Young's modulus of concrete is temperature dependent, the changes in the natural frequencies of the PC girders due to the ambient temperature can be simulated using a finite element (FE) model [15]. Another objective of this study includes performing validation tests of the numerical analyses against the results of the measurement by assuming Young's modulus of concrete as a function of the temperature.…”

Laser heating induced plastic deformation in a pre-elastic-stretched titanium alloy strip

“…Actually, a great many of pre-stressed structures may practice non-uniform temperature elevation due to external localized heating [8,9]. In a structure subjected to tensile stress high enough, the plastic strain will be developed and concentrated on some region wherein the material weakening arises due to the defects or other disturbances, which will in turn enhance the material weakening.…”

Vibration Analysis of Reinforced Concrete Simply Supported Beam versus Variation Temperature

“…Numerical simulations of the bridge were used along with the recorded temperatures and deflections to suggest a possible reason for the observed changes in the natural frequencies of the bridge. Moreover, Xia et al [36] investigated the variation of the structural modal characteristics versus the nonuniform temperature field of the structure. A good linear correlation between the natural frequencies measured and the structural temperatures other than the air temperature or surface temperatures is observed.…”