Based on the information below, find suitable materials to for a fracture plate. The parameters to select from
are compressive strength, Young’s modulus, and fracture toughness.
A fracture plate is a fixation device that is screwed to a broken bone to facilitate healing. It is fully contained
within the body, is permanent and requires open surgery on the limb in question. The aim is to select a
suitable material or materials for a fracture plate. To do this we compare the properties of bone with those of
non-biological bio-medical materials.
The bones of the scull and limbs generally take the form of bi-structured shells or tubes with an outer layer of
dense, cortical (or compact) bone surrounding a foam-like structure of cancellous (trabecular or spongy) bone.
Ideally, the properties of the material for the plate should match those of bone, meaning a compressive strength
in the range 109-208 MPa and a Young’s modulus >22.4 GPa, typical of the femur, humerous, or tibia. Property
matching is important to avoid bone resorption because an overly stiff plate will take a disproportionate fraction
of the load; the body reacts by reabsorbing the lightly loaded bone – a problem encountered also with hip
implants. You want a material that would not be susceptible to fracture so you need to impose a limit for ????????????
therefore, limit this property to a minimum of 60???????????? · ????0.5.