Effects of anisotropy and material axis registration on computed stress and strain distributions in the Turkey ulna

Finite element stress and strain distributions were studied parametrically for a curved long bone using several common material simplifications. A new technique is presented whereby local material axes conforming to local surface topology were automatically computed. Linearly elastic stress/strain solutions were evaluated as a function of the manner in which principal material directions are defined. The simplifications inherent in assumptions of local isotropy or globally registered transverse isotropy led to appreciably different solutions, particularly for some of the lesser-magnitude components of the strain tensor.