跌落冲击损伤条件下的果实非线性黏弹性流变模型

Non-linear Viscoelastic Modeling of the Fruits under Dropping Bruising

基于果实跌落冲击动力学特征,提出一表征其冲击损伤条件下的非线性黏弹性流变模型。以红富士苹果为研究对象,进行多个高度下的跌落冲击试验,基于试验数据识别获得了不同高度下的模型损伤弹性系数、黏性系数以及黏性特征参数。结果表明,与已有模型进行比较,本文提出的理论模型与试验结果吻合性最好;本理论模型与试验结果吻合度高,所提出模型能合理地表征苹果及类似特性果实的非线性黏弹性流变特征。研究结果为果实动态流变特性分析以及模型表征提供了一种新的方法,也为进一步表征果实的黏弹塑性损伤特征提供了基础。

A dynamic non-linear viscoelastic model and its parameter estimated method are developed for the fruits under dropping bruising. This model equation defines the force acting on the fruit as composed of a nonlinear elasticity force kbx^3/2 and viscous damping force cbx^9/2x. A experimental system is used to measure and analyze dropping impact data of fruits. The dropping impact test with multi-heights is conducted on fresh ‘Fuji＇ apples grown in Shandong, China. The model parameters are estimated based on the experimental data of the apples under the multiheights dropping. The efficiency of the model is verified by comparing the results of numerical analyses with the results of experiments. These results indicated that, compared to other model, the proposed non-linear viscoelastic model is the most precise one in simulating the impact force versus deformation during dropping impact of apples.