Abstract:In this study, Korla pear was exposed to pulse excitation to determine the characteristics of its dynamic spectral response, and the frequency spectrum method was used to test its internal quality. The effect of different window functions on the dynamic spectral response curve of the pear was analyzed. Further, the influence of different excitation points, excitation forces, excitation materials as well as the mass, shape, and firmness of the fruit on the characteristics of dynamic spectral response of the Korla pear was determined. The results showed that during analysis of the dynamic signal of the pear, the exponential window function was more suitable to truncate the signal since the processed signal had high signal to noise ratio and less information leakage. Signals from a single excitation and dynamic signals from different excitation points on the equatorial region of the Korla pear were studied. The signal stability was strong and the responses of dynamic spectrum were generally consistent. Changes in excitation material and forces had no significant effect on the dominant response frequency. When a rubber head hammer was used and the excitation force was in the range of 9 to 12 N, the dynamic signal was strong. The dominant response frequency that showed a larger difference in terms of amplitude with the second response frequency was obtained, thus the dynamic signal could be analyzed easily. The mass, shape, and firmness of the fruit showed good linear correlation with the dominant response frequency.
