Image processing-aided FEA for monitoring dynamic response of potato tubers to impact loading

Abstract

Potato tubers suffer from dynamic loads during series of harvest and/or post-harvest operations, leading to the occurrences of mechanical damages. Supervision of dynamic responses upon impact from varied drop heights (200, 400 and 600 mm) onto rigid plate for potatoes was undertaken using finite element analysis (FEA) in this study. Two image processing-aided algorithms were developed and validated with reference methods for creating a potato digital model for FEA and determining the radius of curvature on contact point of the potato. A potato was taken as elastic and viscoelastic models in FEA respectively. The material parameters were derived from compression test and stress-relaxation test. Five response parameters of contact time Tc, peak force time Tp, maximum impact force Fmax, maximum deformation Dmax and coefficient of restitution r were selected to characterize dynamic response of potato collision. Results showed that Tc and Tp decreased slightly with the rise of drop height, while Fmax and Dmax showed positive correlations with drop heights. The value of r stayed high despite of material model and drop height. Dynamic responses presented similar but different values for viscoelastic model compared with elastic model, due to its viscous effect. It was also found that simulation results were highly dependent on modulus of elasticity for both models. Conclusions from this study can be used for monitoring occurrences of damages and solving other agricultural engineering problems with respect to material impact/collision.