Composite Layup Check

As a testing laboratory, we have noticed that errors can occur with fiber layups, specifically when the layup of the material is not what it was intended to be.

For example, we recently received material for Coefficient of Thermal Expansion Testing that was supposed to have a layup of 0-degree plies with +/-60-degree plies but instead we received material made as 0-degree plies with +/-30-degree plies. As a result, new material is required for this testing and our customer has incurred additional costs.

You can save yourself time and money by checking your fiber layups post-production. You can do this by twisting the cured specimens in your hands to see if the specimen’s relative stiffness matches its predicted stiffness. For example, a unidirectional material is very flexible in the 90° direction and fairly stiff in the 0° degree direction. A quasi-directional specimen should be equally stiff in all directions. Via examining the real specimens on a flat table, you can observe the results of off-axis plies or non-uniform resin distribution that will cause bending and/or twist in the specimens.