a) Consider the case in which your tibia is undergoing pure
compression while you are jogging. What are the principal stresses
and at what angle? Calculate the stresses symbolically, then with
actual numbers. State any additional assumptions. Assume:
Periosteal diameter (outer diameter) = 3cm Endosteal diameter
(inner diameter) = 2cm Ebone = 20 GPa σut = 120 MPa σuc = 200 MPa
b) Explain why an oblique fracture pattern occurs under pure
compression. Hint: review material failure theories. You do not
need to look up anything about bone mechanics or materials
properties. Try to guess the materials properties based on the
fracture pattern. c) Explain why a spiral fracture is a tensile
failure in a plane that is 45° from the horizon.