Abstract Summary
This paper presents the application of reverse engineering in assessing the magnitude of dynamic loading on an industry steel structure. The studied steel structure is subjected to a frequently occurring plug load in the pipeline of the conveying system. This dynamic load leads to significant vibrations of the structure, and it is likely to govern the fatigue analysis. To assess the magnitude of the dynamic load, vibration measurements have been performed. Velocities in the transverse, longitudinal and vertical directions are measured at five points throughout the structure for a continuous period of seven days. A finite element (FE) model of the structure is properly set up such that its eigenfrequencies match the dominant vibration frequencies found in the measurement data. Furthermore, a linear time history (LTH) analysis with impulse loading is carried out, to interpret and reproduce the measured vibrations. Two selected measurement transients, one representative excitation and one randomly selected excitation, are used to validate and fine-tune the FE model to match the vibration responses of the structure. The magnitude of the impulse load is tuned such that the response of the analysis model corresponds best to the measurement data in terms of the first and the second peak velocities, as well as frequencies. Based on the results of the FEM analyses, the magnitude of the dynamic load is determined and the maximum occurring stresses are calculated. Besides these, a statistical analysis is performed to determine the distribution of vibration velocities over the entire measurement period. With the combination of vibration measurements, FEM analysis and statistical analysis, a good estimation is made for the amount of stress cycles in 50 years, which can be further used in the fatigue analysis of the steel structure.
