Wednesday, July 18, 2012

The idea beyond fiber construction

There are many applications in our lives that use the fiber construction of materials like clothes, nylon ropes, steel ropes, fiber-glass, etc. In this post I’m going to consider the idea beyond using fiber construction in mechanical applications. Consider the figure below which represents two samples of the same material: one with continuous layout and the other is fiber-constructed and admire it.

Assume that those two samples are going to carry the same load with the same safety factor in the shown direction (direction is parallel to fibers in this case). Also, consider the presence of a crack (which may take place in our practical life) to the right of both samples. If the load is still applied on both samples, the crack will propagate till it reaches the other end of the sample as shown (end of crack propagation). On the other hand, the crack in the fiber-constructed material will terminates at the end of the fiber and the remainder of the fibers can carry the load, but with lower margin of safety.

So, and for this reason, the fiber construction is more preferable for being used in high safety applications like airplane (body is made of aluminum-carbon fibers), hoisting systems (cranes, lifts, …), three-bladed conventional wind turbines, and all other applications.