Biomechanical behavior of bovine periodontal ligament: Experimental tests and constitutive model.
A viscohyperelastic constitutive model with the use of the internal variables approach was formulated to evaluate the nonlinear elastic and time dependent anisotropic mechanical behavior of the periodontal ligament (PDL). Since the relaxation response was found to depend on the applied stretch, the adoption of the nonlinear viscous behavior in the present model was necessary. In this paper, Helmholtz free energy function was assigned to the material as the sum of hyperelastic and viscous terms which is based on the physical concept of internal variables. The constitutive model parameters were evaluated from the comparison of the proposed model and experimental data. For this purpose, tensile response of the bovine PDL samples under different stretch rates was obtained. The good correspondence between the proposed model and the experimental results confirmed the capability of the model to interpret the stretch rate behavior of the PDL. Moreover, the validity of structural model parameters was checked according to the results of the stress relaxation tests.
Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran.
Iman Z
IZ
Oskui
Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran. Electronic address: a.hashemi@aut.ac.ir.
Ata
A
Hashemi
Faculty of Dentistry and Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Hamid
H
Jafarzadeh
D000818:Animals; D016880:Anisotropy; D001696:Biomechanical Phenomena; D002417:Cattle; D004548:Elasticity; D008954:Models, Biological; D010513:Periodontal Ligament / Q000502:physiology*; D013314:Stress, Mechanical; D013718:Tensile Strength
Experimental test; Nonlinear viscoelasticity; Periodontal ligament