DYNAMIC CHARACTERISTICS OF INTACT PEAR
In this article, dynamic equilibrium is determined according to sinusoid stress-strain. Experiments were conduced 
to measure the complex modulus of intact Dangshan pears, the phase angle by which the strain lagged the stress, and their 
relationship with initial pre-load and vibration input power over a range of frequencies. Both the complex modulus and the 
phase angle increased as the frequency increased from 20 to 200 Hz. Initial pre-load had a significant effect on the complex 
modulus, but not on the phase angle. Vibration input power had no significant effect on the complex modulus and the phase 
angle. The ripeness of pear had a significant effect on the complex modulus, but not on the phase angle. The firmness had 
positive correlation with the complex modulus and negative correlation with the phase angle. The coefficient of determination 
(R2) of the quadratic relationship between the complex modulus and firmness, and between the phase angle and firmness was 
0.92 to 0.93.