Tensile strength or ultimate strength is the maximum stress that a material can withstand while being stretched or
pulled before necking, or failing. Necking is when the sample cross-section starts to significantly contract. If you take a
strip of plastic bag, it will stretch and at one point will start getting narrow. This is necking. It is measured in Force per
Unit area. Brittle materials such as carbon fiber do not always fail at the same stress level because of internal flaws.
They fail at small strains. (in other words there is not a lot of bending or stretching before catastrophic failure)
Weibull modulus of brittle materials
Testing involves taking a sample with a fixed cross-section area, and then pulling it gradually increasing the force until
the sample changes shape or breaks. Fibers, such as carbon fibers, being only 2/10,000th of an inch in diameter, are
made into composites of appropriate shapes in order to test.Units are MPa this table is offered as a comparison only
since there are a great number of variables.