Determining tangential contact force model parameters for viscoelastic materials (apples) using a rheometer

Van Zeebroeck, M.; Dintwa, E.; Tijskens, E.; Deli, V.; Loodts, J.; De Baerdemaeker, J.; Ramon, H.

doi:10.1016/J.POSTHARVBIO.2004.02.008

Title

Determining tangential contact force model parameters for viscoelastic materials (apples) using a rheometer

Author

Van Zeebroeck, M.

Dintwa, E.

Tijskens, E.

Deli, V.

Loodts, J.

De Baerdemaeker, J.

Ramon, H.

Abstract

A computer model, based on discrete element method (DEM), can simulate damage to fruit during handling. A contact force model is one of the basic ingredients of a DEM model. A rheometer device was used to measure and validate a tangential contact force model for 'Jonagold' apples. The Mindlin and Deresiewicz model for torsion was used to simulate quasi-static torsion and extended to include a viscous term in order to simulate dynamic torsion. The measured parameters were the dynamic friction coefficient, the shear modulus and the viscosity of the apples. For model validation purposes, the angular deformation, the torque, the contact surface and the normal force were measured as well. The model describes, in a satisfactory way, the phenomenon of slip-stick at the contact surface of the apples. By adding the viscous term, the model was improved. (C) 2004 Elsevier B.V. All rights reserved.

Language

English

Source (journal)

Postharvest biology and technology: an international journal. - -

Publication

2004

ISSN

0925-5214

DOI

10.1016/J.POSTHARVBIO.2004.02.008

Volume/pages

33 :2 (2004) , p. 111-125