Week 1-Materials Flashcards
What are Fiber Reinforced Plastics?
Carbon Fibers in plastic
What forces does fiber reinforced plastics enforce?
Tension, Sheer, Compression
What is Polymer Composite?
Single Layer of Resin and Fiber
What is a disadvantage of polymer composite?
May not have continuous fibers
What is Laminar Composite?
Layers of Resin and many other materials such as fiber
What is critical for laminar composite?
Fiber orientation, it increases strength in the direction the fibers are oriented.
What materials can be used for Laminar Composite?
Kevlar, hybrid matrix, nylon, nyglass, fiberglass, and dacron
What is Kevlar?
Material used for bullet proof vests, impact resistant, heavy
What is nyglass?
A hybrid between nylon and fiberglass
What makes laminar composite better than a polymer composite?
Has continuous fibers throughout the device.
When determining the layup what is important to know?
The weight of the patient
What are resins made of?
A promoter and an activator/hardener
Why should you use different fibers in one device?
Can adjust the fiber orientation
Carbon is strong in compression and tensile forces, not in sheer and torque
What are the different aspects of carbon fiber?
Strong per-weight Highly moldable to complex forms Weak when purely planar Potentially expensive raw materials Potentially toxic byproducts of production
What makes carbon strong?
Strength is achieved on a per-fiber basis with each fiber made up typically of one plane of carbon in a crystaline structure along the fiber’s length.
What is typical of short, less pure or planar fibers?
They break. Long fibers are stronger
What can cause sliding among carbon?
I-Beam Theory/Sandwich Effect/Parallel Fibers Property-These carbon planes have a high modulus of elasticity in their plane, but when stacked, slide easily on each other due to very weak out of plane bonds. Need buffer material between the two pieces of carbon.
What can be used as reinforcing materials between carbon?
glass, aramid, polyester, paper or cotton
What is Lamination code?
Explains the direction of each layer of fiber, the number of plies and the coding.
Example
[0,45,90]2
The subscript is the number of plies while the numbers are the direction of the fibers.
What is the purpose for different fiber directions?
The load can be carried through the fibers in a number of different positions and loading situations
