. Author manuscript; available in PMC: 2019 Jun 1.

Published in final edited form as: J Biomech Eng. 2018 Jun 1;140(6):10.1115/1.4039173. doi: 10.1115/1.4039173

Table 3.

Principal stress directions at the two ends of the fatigue cycle (unit vectors are shown in local coordinate system)

		Unit vector at first peak of fatigue cycle	Unit vector at second peak of fatigue cycle
1.05% cyclic axial deformation	Principal-1 direction	(0.9995, 0.0309)	(0.9995, 0.0306)
1.05% cyclic axial deformation	Principal-2 direction	(−0.0309, 0.9995)	(−0.0306, 0.9995)
10 degree cyclic torsion (superimposed on a 1.05% tensile preload)	Principal-1 direction	(0.9524, 0.3048)	(0.9806, −0.1962)
	Principal-2 direction	(−0.3048, 0.9524)	(0.1962, 0.9806)