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Human Musculoskeletal Biomechanics Part 10

Tham khảo tài liệu 'human musculoskeletal biomechanics part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | TMJ Biomechanics 171 Fig. 7. Maximum von Mises stress developed over the mandibular 3D model during three FE simulations - for three values of Young s modulus E - under four loading conditions. Fig. 8. Material properties were assigned to the 3D finite element volume mesh of the mandible using individual masks for each component. The cortical bone portion is indicated by yellow color condylar cartilage by orange color and teeth by red. As cancellous bone is covered by cortical bone it is not visible in this figure. 172 Human Musculoskeletal Biomechanics Fig. 9. Three-dimensional finite element volume mesh of the mandible. The volume mesh had 37439 nodes and 23156 ten-node quadratic tetrahedral elements C3D10 . Part Young s Modulus MPa a b Poisson s Ratio a b Cortical bone 1.47E 04 0.3 Cancellous bone 4.90E 02 0.3 Teeth 1.76E 04 0.25 Cartilage 6.1 0.49 Sources aIchim et al. 2006 bReina et al. 2007 Table 2. Material properties assigned to different components of the mandibular FE model. The mechanical behavior of the mandibular model was assumed to be linear-elastic homogeneous and isotropic. The model constraints were applied to imitate the in-vivo movements of the mandible as accurately as possible during each loading condition. Since the mastication forces are the result of the pressure in the teeth-food contact Reina et al. 2007 the displacements were simply restrained at the nodes of the surface of the lower teeth that come in contact with the food or the upper teeth. During the balanced occlusive loading both condyles were permitted translation of 10 mm in anterior-posterior direction and rotation of 11o along the medio-lateral axis. Same constraints were employed to simulate the unbalanced occlusive loading and bi-lateral molar clenching. During teeth grinding the forces were applied on first and second molars and second premolar on right side only and the right condyle was assumed free to move while the articular surface of the left condyle was constrained as