Experimental Research On Dynamic Property And Bruising Of Fruits In Corrugated Box During Simulated Transports

Reducing damage of fruits has become one of main concerned problems for agricultural industry of the world. Fruits are susceptible to the static pressure, extrusion, vibration and dropping during transport. It forms mechanical damage, which is the main reason of fruits damage. From the real transport environment, the dropping and vibration loading properties of fruits were briefly analyzed in this paper. And the bruising and dynamic properties of apples were studied due to dropping and vibration loading.The apples in the box with four different cushion packaging construction were tested under three different heights. The result showed that the protection of construction with corrugated pad and sheet to apples is the best; the most serious damaged apple is always on the bottom with the same condition, and the bruising volume reduces gradually from the bottom to top layer; total bruising volume of apples in the box increases with the increasing of dropping heights, and there is a linear relationship between them, and the linear regression equations are received for apples bruising.The three factors influencing bruising and vibration transmissibility of apples, including vibration acceleration, cushion packaging construction and layers of apples in the boxes were discussed based on orthogonal experiments. The result showed that bruising and vibration transmissibility of apples are both affected by the three factors, and vibration acceleration has significant effect on bruising ratio of apples, the significance of packaging construction and layers of apples follow by in sequence. Compared with different vibration experiments, results showed that the protection of construction with corrugated pad and sheet to apples is the best under the same outside power; and the bruising volume of middle layers was the largest, and more serious than that of the bottom, and the bottom still more than that of the top. The result of comparison between sinusoidal vibration test at constant frequency and random vibration test was that the affection to apples for the latter was small.The accelerations of every-layer apple in the box were also conducted by new method with the help of INV306D intelligent signal collection and analysis system and DASP software. The result showed that, for dropping test, the biggest acceleration of apples was always on the bottom, and they reduces gradually from the bottom to top layer; for vibration test, the accelerations of every-layer apple increases gradually from bottom to top layer.Quadratic relationship between bruising volume and acceleration peak value of every-layer apple for dropping experiments were obtained. And result of vibration tests showed that with the decreasing of vibration transmissibility, bruising ratio of apples reduces.The demand and method of fruits packaging design were also carried out, and the cushion packaging construction for meeting certain bruising ratio and grading of apples were also conducted.