Glass fibers are made from molten glass extruded at a specified diameter. The fibers are gathered into bundles and the bundles combined create a roving. Roving’s are a continuous rope, similar to twine, and are wound on a mandrel to form a ball called a doff. Reinforcements for FRP are made from roving’s that are either chopped into short strands or woven into a cloth.
There are many factors that affect the reinforcement characteristics of fiberglass:
- Fiber and bundle diameter and type of glass
- Direction of the fiberglass reinforcement
- The amount of fiberglass reinforcement
- The physical contact (wet out) of the fiber with the polymer
- All of these factors must be taken into account when designing an FRP composite so that the required physical property strengths are met.