Comparison of Tensile and Compressive
Properties of Chicken Cortical Bone
Name: Ashley Stein
Class: BE 210
It is hypothesized that the ultimate stress of chicken cortical bone will be higher in compression than in tension. Ultimate stress in tension will be determined using a three point bending test, and ultimate stress in compression will be determined using a uniaxial compression test. As a composite material, bone shows mechanical properties of all of its components, most noticeably collagen and hydroxyapetite. Because the most abundant component of bone is hydroxyapetite, it is hypothesized that its mechanical properties will be similar to those of a crystalline ceramic – stronger in compression than in tension.
Wood surrogates will be tested prior to the bone not only to allow students ample opportunity to learn to use the Instron and the saw, but also to test a more uniform material. Wood is anisotropic, like bone, and has also been shown to have differing compressive and tensile strengths. However, the shape and size is easier to work with than bone. A sub-goal of this experiment will be to compare the ultimate stress in tension and in compression, like the bone experiment, to determine if wood is a good surrogate for the composite properties of bone. It was found that the values for ultimate stress differed significantly for bone and wood, 161±30MPa and 78±10MPa respectively, indicating that the overall loads that the two materials can bear are different. However, this experiment may show that the relationship between compressive and tensile properties is similar among bone and wood.