ABSTRACT
Chapter 2 introduces bone structure, including its material properties. Bone is composed of both fluid and solid elements. In its solid part, apatite crystals are inserted into collagen to build a composite material that makes bone structure, with the Young's modulus between that of apatite and collagen. Bone structure also changes relevant to its stress-state. For perspective on the material properties of bone, bone is linear in a particular range of the strain and is very sensitive to the strain rate. Compared to cortical bone, cancellous bone is extremely anisotropic and nonhomogeneous. However, cortical bone is more than 40 times stiffer than cancellous bone, which makes cortical bone sustain greater stress, but less strain before failure.
