Figure 5.

Deformation and strain regimes in the working-side corpus and ramus. Strain scale in G applies to principal, axial and shear strains. A, B) Deformation regime: the left side is the working (biting) side, the right side is the balancing-side; the left P₃, P₄, and M₁ are constrained against all displacements; the deformed model is transparent; the undeformed model is solid; deformation scale factor is 70. Red arrows connect homologous points between undeformed and deformed models, curved black arrows indicate negative torsion of working-side mandible. Thick black arrows indicate vertical force components: F_m.bal = balancing-side muscle force transmitted across the symphysis; F_bite = bite force; F_m.wk = working-side muscle force; F_j.wk = working-side joint reaction force. C, D) Transverse shear strain and AP twisting: alternating positive and negative transverse shear strain along the top (C) and bottom of the working-side corpus (D) are associated with alternating patterns of AP twisting. E) Maximum (ε₁) and minimum (ε₂) principal strain regimes in lateral surface of working-side mandible. F) Shear forces acting along the working-side mandible. G) Sagittal shear strain on lateral surface of balancing-side mandible. Sagittal shear strains are positive between the bite force and F_m.bal, negative between F_bite and F_m.wk, and positive between F_m.wk and F_j.wk. H-N) Anteroposterior (AP) strains (J, K, L) and principal strains (H, I, M, N) associated with sagittal bending of working-side mandible. Minimum principal strain (ε₂) on the top of the working-side mandible (in H) are primarily due to AP compressive strain (in J). Maximum principal strains (ε₁) in base of mandible (in M) are primarily due to AP tensile strain (in L).