Lower Residual Limb for Prosthetic Socket Design - Computational Biomechanics of the Musculoskeletal System - page 159

Anterior view Posterior view

(MPa)

Resultant shear
+ 7.693e - 02
+ 7.052e - 02
+ 6.411e - 02
+ 5.770e - 02
+ 5.129e - 02
+ 4.488e - 02
+ 3.847e - 02
+ 3.206e - 02
+ 2.564e - 02
+ 1.923e - 02
+ 1.282e - 02
+ 6.411e - 03
+ 0.000e - 00

65 kpa

52 kpa

58 kpa

77 kpa

(a)

(MPa)

Resultant shear
+ 7.693e - 02
+ 7.052e - 02
+ 6.411e - 02
+ 5.770e - 02
+ 5.129e - 02
+ 4.488e - 02
+ 3.847e - 02
+ 3.205e - 02
+ 2.564e - 02
+ 1.923e - 02
+ 1.282e - 02
+ 6.411e - 03
+ 0.000e + 00

60 kpa

18 kpa

35 kpa

31 kpa

(b)

FIgure 13.5 (See color insert.) The anterior and posterior views of resultant shear stress distribution
(a) with pre-stress considered and (b) with pre-stress ignored upon application of 800 N.

Stress distribution patterns over the residual limb and peak stress values over the four pressure-
tolerant regions were different in the second model, which ignored pre-stress and incorporated a
simplifying assumption that the shape of the limb and rectified socket were the same. Figure 13.4b
shows the normal stress distribution and Figure 13.5b shows the resultant shear stress distribution
over the limb upon application of 800 N to the second model. Stresses were more evenly distributed
in the second model. Peak normal and resultant shear stresses were lowered over the four pressure-
tolerant regions where socket undercuts were made, but higher stresses fell on regions that were not
pressure tolerant.