A void is a pore that remains unoccupied in a composite material. A void is typically the result of an imperfection from the processing of the material and is generally deemed undesirable. Because a void is a non-uniformity in a composite material, it can affect the mechanical properties and lifespan of the composite. Voids can act as a crack nucleation site as well as allow moisture to penetrate the composite and contribute to anisotropy of the composite . This is an issue because crack formation and propagation can create unpredictable behavior in the laminate. For aerospace applications, a void content of approximately 1% is appropriate for performance while other grades of composites can have between 3%-5% void content. A small change in the percentage of void content may not seem like a large problem however for a loaded carbon fiber laminate composite, a 1%-3% increase in void content can reduce the mechanical properties of the composite by up to 20% Void content in composites is represented as a ratio, also called void ratio, where the volume of voids, solid material, and bulk volume are taken into account. Void ratio can be calculated by the formula below where e is the void ratio of the composite, Vv is the volume of the voids, and Vt is the volume of the bulk material.