Correlation of X-Ray CT Measurements to Shear Strength in Pultruded Composite Materials

Pultrusion is an emerging, economical manufacturing process for composite structures. In a pultrusion system, the composite tapes and fabrics are loaded onto a creel, and the materials are fed into a preform (or shaper), along with any fillers that may be needed. If the fiber is not yet preimpregnated with resin, it is run through a resin bath or resin is injected into the die the material is about to enter. The composite is pulled through the heated die and then cut from the system to produce either a fully or partially cured product. This handleable part is then placed in an autoclave for final cure. A number of variables go into the pultrusion process, including the type of fibers, the resin matrix material, pull rate and cure temperature. Destructive testing, such as shear testing of small sections, is the normal method for assessing the quality of the pultrusion manufacturing product. During manufacture, this cannot be performed on the actual product to be used but only on near neighbor test coupons. This can be time consuming, costly, and part of the product is destroyed