Fig. 10.

Strain vector plots of strain data collected from dorsal orbital surfaces of the supra-orbital torus. The top figure shows the strain field of maximum principal strain orientations at the centroid of each element. Note that the strain field vectors values were not transformed into the coordinate system of the model surface, which the strain gages sample, whereas the bite point means were appropriately transformed. The second figure illustrates in silico data from corresponding ‘gage sites’ on the model. For the in silico data, each line is a vector representing the mean orientation and magnitude of maximum (ε₁) (red to yellow) and minimum (ε₂) (blue to green) principal strains from all the elements at the gage site. Note that the variance among the vectors from the in silico gage sites is due to variation in bite point, and the variance among vectors from in vivo gage sites is due to variation in magnitude and location of bite force, joint reaction forces and muscle forces. The in vivo strain vectors for experiment 47 are shown in the third figure. In vivo strain orientations are presented in Table 4 as angles relative to the plane of the orbital aperture. Also shown is the range of ε₁ vectors recorded from the dorsal orbital site during three experiments reported by Hylander et al. (1991). Strain data for the balancing side shown in the skull's left orbit were actually recorded from within the right orbit: they are illustrated on the left side after reflecting them about the mid-sagittal plane. The black arrows on the in vivo plots represent the extremes of the ranges of the mean ε₁ orientations from the in silico‘gage sites’.