Random mats consist of continuous or chopped fibers laid randomly and held loosely together by a binder adhesive. Advantages of this form include its high permeability and hence the ready flow of resin in the infusion step for thorough wet-out, easy handling for placement in the mold and good structural integrity. Some limitations are its relatively poor stiffness and strength, the lack of control of fiber orientation, and the ability to achieve only limited fiber volume fractions. The random fabric consists of loose strands laid together. Because of the randomness, the mat is isotropic, or nearly so.
Fluid flow is relatively easy to predict in random materials.
A further effect of the random fiber orientation is that draping the fabric over a tool does not cause much preferential orientation. No orientation control Limited fiber volume fractions Two-dimensional woven fabrics are fabricated on a loom from at least two sets of tows that are interwoven. Balanced properties in the plane of the fabric are thus achieved, although there can be some asymmetry depending on the type of weave pattern. Wovens also exhibit good impact resistance. On the other hand, these materials have poor conformability for placement in odd-geometry molds.