Research On Fruit's Vibration Performances And Protective Packaging

Nowadays, 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. Taking pear as an example in this paper, its mechanical performance had been researched and on this foundation pear's vibration bruising performances in single, four layers and several packaging had been studied thoroughly. Fruit's mechanical performance presents fluidity like liquid and elasticity like solid, which was usually expressed as viscoelasticity. Fruit's viscoelasticity would change according to the environment outside. When fruit was vibrated, its viscoelasticity will change as the vibration time became longer. Three parts viscoelastic model was built to research pear's creep performance which will change according to vibration time. Through taking vibration time into three parts model, vibration-creep model was built and its parameters were determined too. Experiment's result presented that creep of pear became bigger as the vibration time became longer. Organization and structure of fruit's bruising changed because of vibration and this will affect the viscoelasticity. It displayed as modulus of elasticity E1,E 2in the viscoelastic model would became small as vibration time became longer. Through fitting E1,E 2 and vibration time, fitting equations of E1,E 2 and vibration time were got.Vibration responses of fruit will affect the damage of fruit when they were transported and fruit's packaging designing. Single and four layers pears'vibration performances were researched through experiments. Pear's transmissibility was analyzed, which presented pear's vibration responses expressed non-liner performance. On this foundation, non-loner vibration model was built and its parameters were determined as well. On the other hand, bruising performances of single and four layers pears were researched and single pear's vibration-bruising mathematic model was built through fitting.Fruit is a kind of product which is still alive. Metabolism of fruit still carried out when fruit were transported and all factors in the transportation would have some affection on the bruising of fruit. It is very important to research the vibration bruising of fruit in the real transporting conditions. A suitable PSD curve was found through analyzing our country's transporting conditions. Using this PSD curve and MTS vibration system, the real transporting conditions were imitated in the lab. In this way, pear's vibration bruising in several kinds of packaging was researched. The result represented that packaging, vibration time and the layers all had affections on the bruising of pear. In general, simple packaging, more vibration time and higher layer will lead to larger bruising. But, interactions of the factors were also existed, only when one of the factors became the mainly reason, the bruising of pear would express the corresponding performances.At last, fruit's reducing fruit's damage packaging was researched. Using all the results above, which ranks of pears can be reached in four kinds of packages and different transport time was researched. In addition, the problems in fruit currency environment were analyzed. The fruit currency environment in our country is very harsh. It is very important to reduce those hazards in the environment, which would do harm for the fruit packaging, or the packaging will not carry out its function as it used to be.