Journal of Hunan Agrichltural University (湖南农业大学学报) 2013/39:6 PP.688-692
In order to investigate the damage rule of litchi by extrusion in harvesting, storing and transporting, we have studied the effects of extrusion conditions on mechanical damage and mechanical parameters of litchi by using the possible factors causing extrusion damage as test factors(including compression ratio, extrusion material, extrusion direction and extrusion speed) , and by loading and unloading orthogonal tests. The results show that the factors which have significant effects on the extrusion mechanical damage of litchi are compression ratio, extrusion direction, extrusion material and extrusion speed in turn. The average ratio of mechanical damage of litchi raised by 3.03% as the compression ratio increased by 1%. When the extrusion material is the rubber, the ratio of mechanical damage of litchi is the lowest. The extrusion direction is the most significant factor for litchi’s elasticity while compression ratio is the most significant for the other mechanical parameters; and the litchi’s elasticity in the horizontal direction is greater than in the vertical direction. When the compression ratio increases, the elasticity decreases and the other mechanical parameters raise . The determinant coefficient of the relation equation between the extrusion mechanical damage and the mechanical parameters of litchi is 0.913, and the most relavant mechanical parameters to the extrusion mechanical damage of litchi are the peak pressure and elasticity level. The research can provide theory evidences for the derogation design and development of litchi operation equipments.