lab 6 report

lab 6 report - Roshan George Parvinder Singh Dipen Patel In...

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Roshan George Parvinder Singh Dipen Patel In lab, Dipen, Roshan and Parvinder performed the experiment and collected the datat. The lab report was written together by all three students. Lab#6:Viscoelastic Behavior of Bone EGRB 310: Biomechanics Date of Lab: 11/07/07 (Wednesday 1pm-4pm) Date Due: 11/14/07 PLEDGE: ______________________________________ Our signatures attest that each lab partner within our group contributed equally to and is well versed in all parts of this report.”
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Abstract: In this lab, harvested and simulated bone were used to represent cortical and trabecular bone. Compression was applied to both the types of bones in order to examine their response and behavior in different modes of loadings. Both cyclic and stress relaxation tests were performed on both types of bones at different speeds and different endpoints. The MTS frame, Test Works 4 program, a digital caliper, and an extensometer were used to perform the experiment. The main results that were obtained from this experiment were that ____________________________________- . Nomenclature : Gage length – length between two grips Inner minor diameter – the inner diameter on the thinner end of the bone Outer minor diameter – the outer diameter on the thinner end of the bone Inner major diameter – the inner diameter on the thicker end of the bone Outer major diameter – the outer diameter on the thicker end of the bone Width and thickness – measured for the simulated (polyurethane) bone Cross-sectional area – width multiplied by thickness for the specimens Test speed – rate at which crosshead moves (mm/min or %/sec) Endpoints – the points until which strain is applied (% or mm) Stress relaxation – deformation of a material in order to study the stress response Hysteresis – difference between loading and unloading Tension – direction of loading (Newtons) Strain – change in length/original length Stress – force/area Modulus of elasticity – stress/strain Y – yielding F – Fracture M – Modulus B - Beginning Objective: The purpose of this lab was to investigate the viscoelasticity of cortical and trabecular bone, which was represented by harvested bone and polyurethane foam. They were put in compression for cyclic and stress relaxation tests and their behaviors was observed and analyzed. Theory: Bone is made up of 2/3 hydroxyapatite and 1/3 organic material, most of which is collagen. The arrangement of this collagen is one of the many factors that affects bones’ mechanical properties. Other factors include age, gender, species, bone location, load orientation, strain rate, and whether the bone is dry or not. The rate of loading, in particular, has an affect on the elastic modulus and ultimate strength. Both increase as the strain rate is increased. In addition, loading in a longitudinal direction yields a different modulus and strength than a loading in the transverse direction. Same affect is seen in the case of compressive, tensile or shear
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This lab report was uploaded on 04/18/2008 for the course EGRB 310 taught by Professor Wayne during the Fall '07 term at VCU.

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lab 6 report - Roshan George Parvinder Singh Dipen Patel In...

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