An Uncertainty Analysis Method of Frequency Response Function Based on Equivalent Frequency Discretization

Abstract

The invention relates to an uncertainty analysis method of frequency response function based on equivalent frequency discretization, which relates to mechanical design. Divide the frequency response function into several monotone areas; resample the same area of ​​each frequency response function according to the same number of frequency points to obtain the equivalent frequency; after discretizing the equivalent frequency of the frequency response function, obtain the uncertainty quantification The formula is used in the uncertainty analysis of the frequency response function. It is suitable for the dynamic analysis of the uncertain structure in the process of mechanical design, and uses the scale under the random equivalent frequency to analyze the uncertainty of the frequency response function, so that the uncertainty is mapped between the system parameters and the frequency response function The degree of nonlinearity is reduced, and the transmission is more stable, so that the obtained uncertainty statistics of the frequency response function, such as mean value, variance, confidence interval, etc., are closer to the real value during evaluation, which is more reasonable and has physical meaning. It is also applicable to related fields such as structural reliability analysis and model correction.

Description

Technical field [0001] The present invention relates to a mechanical design, in particular to a frequency response function uncertainty analysis method based on equivalent frequency discrete frequency uncertainty analysis may be applied to the frequency response function cognition and stochastic uncertainty analysis. Background [0002] Modern mechanical design is increasingly moving in the direction of low cost and high reliability. Considering the deviation of various design parameters in the design stage, the geometric tolerance during the manufacturing assembly process and the damage deformation during transportation and use, the performance and life of the structure are relatively dispersed, and the traditional deterministic analysis technology and the safety factor method no longer meet the design requirements of complex mechanical systems in real engineering, so the structural uncertainty analysis technology has gradually developed. The frequency response function (FRF) o...

AI Technical Summary

Problems solved by technology

The frequency response function is a spectral line in a two-dimensional plane, which makes the traditional uncertainty quantification method for scalar quantities no longer applicable. At the same time, its response value has strong nonlinearity with frequency changes, and the response at different frequency values The sensitivity to parameters varies greatly, which also makes it difficult to intuitively reflect uncertainty information when comparing frequency response functions under the same frequency scale. Therefore, it is urgent to develop new methods suitable for the characterization and analysis of frequency response function uncertainty.

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