Elasticity & Young's Modulus for Tissue Analysis
Biomedical engineers design new devices to solve problems related to our health and how our bodies function.Copyright (top) 2013 OpenStax College, Wikimedia Commons; (bottom) 2014 Stif Komar, Wikimedia Commons
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As part of the engineering design process to create testable model heart valves, students learn about the forces at play in the human body to open and close aortic valves. They learn about blood flow forces, elasticity, stress, strain, valve structure and tissue properties, and Young's modulus, including laminar and oscillatory flow, stress vs. strain relationship and how to calculate Young's modulus. They complete some practice problems that use the equations learned in the lesson—mathematical functions that relate to the functioning of the human heart. With this understanding, students are ready for the associated activity, during which they research and test materials and incorporate the most suitable to design, build and test their own prototype model heart valves.
Materials are an important aspect of new technology and new product designs created by engineers. When biomedical engineers design objects and devices to serve as replacement parts and organs in the human body, materials are especially important because the artificial parts must reliably perform inside living people. So, engineers study and analyze real body parts, such as heart valve tissue, in order to understand their structures, properties and behavior. They also research and test (and sometimes design new) materials that are suitable to fabricate artificial parts that function as close as possible to real parts. To do this, they determine the forces that body parts must withstand in the body, how the tissues respond, and other factors and measured characteristics such as stress, strain, elasticity and Young's modulus.
After this lesson, students should be able to:
- Describe the forces encountered in the human body to open and close aortic valves.
- Define Young's modulus and how it relates to the properties of valve tissues.
- Determine the Young's modulus for a material by calculating the materials' stress and strain and creating a stress vs. strain graph.
- Calculate Young's modulus for various materials and use the Young's modulus, stress and strain equations to calculate unknown values, such as force.