Fig. 8.
Simulated local stretch during swallowing. Local stretch is defined as λp = tLp/Lop = (1 + tUp)/Lop. Because, as the length of parallel elastic component is equal to the muscle length (Fig. 3), i.e., tLp = tL, the local parallel elastic stretch λp is equal to macroscopic stretch in Gaussian point of a FE, λ (Eq. A1). The color code represents the magnitude of the muscle stretch in direction of muscle fibers ξ. Stretch in the direction of indicated muscle fibers may be displayed as regions of compression (gray) or extension (red). The pattern of stretch displayed is similar to that exhibited by passive stress (Fig. 7), although relative magnitudes are skewed due to material and geometric nonlinearities.