Key Concepts
- Blood forced through heart and vessels whenever heart pumps
- Valve opens due to structure of self and flow of blood
- Laminar flow: fluid flowing in parallel layers with no disruption between layers
- Occurs in ventricle with blood flows
- Oscillatory flow caused by closed valve
- Occurs in ventricle with blood flows
- Diastole: the part in the heartbeat where the pumping stops and muscles relax
- In this phase, the blood flow changes and pushes back on the heart, which causes the aortic semilunar valve to close
- This causes collagen to slightly move and elastin in the ventricularis layer to stretch
- Doing this completely seals the valve and prevents blood regurgitation
- In this phase, the blood flow changes and pushes back on the heart, which causes the aortic semilunar valve to close
- Force: f=ma (mass x acceleration)
- Young’s Modulus: number that measures an object or substance's resistance to being deformed elastically (non-permanently)
- Stiffer the material = higher the Young’s Modulus
- F = 𝒀( ∆𝑳/𝑳𝟎 )𝑨
- Stress over strain along an axis, measured in Pascals
- Stiffer the material = higher the Young’s Modulus
- Stress: force divided into a cross-sectional area: σ= F/A (A is the area of the material)
- Strain: change in length divided by original length: ɛ=∆𝑳/𝑳𝟎
- Once stress is removed, elastic items such as rubber bands recoil
- If too much stress is exerted, the elastic item will be permanently deformed
- If the stressed item is checked into a mental hospital, the elastic item will be permanently reformed.
- If the stressed item is checked into a mental hospital, the elastic item will be permanently reformed.
Our Project
For this project we designed a model heart valve that stayed open while resting and closed when pressure was applied to it. To do this, we took inspiration from "ball and cage" heart valves and added our own variation to the design. We were also required to have some elastic component, which led to us including an elastic, spring cage. This cage keeps our ball trapped in a large section of tubing, while the other end is kept in by using a smaller tube then the ball can fit through.