The effect of tow grouping resolution on shearing deformation of unidirectional non-crimp fabric

In the rapidly growing large-scale composites industry, specifically in the area of wind turbine blade manufacturing, reducing costs through reduced man-hours and materials while simultaneously increasing quality has become a major focus. One strategy is to automate the manual lay-up process. Automation techniques used in the aerospace industry are too costly for wind turbine blade manufacturing; therefore, new techniques need to be investigated. This research describes a new fabric pre-shearing process to reduce out-of-plane deformations during the lay-up process that enables automated deposition of unidirectional non-crimp fabrics (NCF) in molds. This new process controls the manipulation of broad-loom NCF fabrics such that fabric geometry is well controlled, reducing the need for naïve and inconsistent manual lay-ups. Previous research modeled the behavior of NCF fabric in order to predict the final characteristics of the fabric after shearing. However, this model was never validated with NCF fabric. The goal of this research was to determine the effects of shearing process parameters on NCF fabric geometry and validate the predicted characteristics generated by the previous shearing model. An empirical study of fabric shearing was conducted and the analysis of fabric samples transformed by the pre-shearing process is presented. A comparison of the conformance of un-sheared fabrics to pre-sheared fabrics shows that fabric pre-shearing reduces out-of-plane deformations and produces consistent fabric geometry