Characterizing friction for fiber reinforced composites manufacturing: Method development and effect of process parameters. (1st May 2022)

• Record Type: Journal Article
• Authors: Das, Arit; Choong, Gabriel Y.H.; Dillard, David A.; De Focatiis, Davide S.A.; Bortner, Michael J.
• Is Part Of: Composites. Number 236(2022)
• Publication Date: 2022-05-01
• Subjects: Carbon fiber -- Prepreg -- Rheological properties -- Optical microscopy -- Friction; Composite materials -- Periodicals; Materials science -- Periodicals; Composite materials; Periodicals; Electronic journals; 620.118
• DOI: 10.1016/j.compositesb.2022.109777
• Languages: English
• ISSNs: 1359-8368

Abstract

Abstract: In automated layup manufacturing processes of fiber-reinforced polymer composites, the quality of the manufactured part is strongly dependent on frictional behavior. Improper control of frictional forces can lead to defect formation. Frictional sliding rheometry tests provide an innovative methodology to accurately characterize the tool-ply friction of unidirectional (UD) prepreg employing unique annular plate geometries. The effect of processing parameters (temperature, velocity, and normal force) on the frictional response of a carbon fiber prepreg was studied. Moreover, utilizing custom designed plate geometries coupled with optically transparent fixtures allowed for in-situ quantification of the prepreg-rigid surface contact area along with simultaneous characterization of the process parameter-dependent frictional mechanisms. Our findings highlight the reduction in frictional forces with increasing temperature, attributed to the increased resin flowability, while increases in sliding rates resulted in a pronounced increase in the frictional forces. The effect of applied load on the frictional characteristics was more complicated due to contributions from both the adhesive and normal forces. Finally, the results were interpreted in light of the contact area measurements performed at different temperatures, normal force, and sliding rate. Highlights: Frictional sliding properties of carbon fiber prepregs are characterized with an annular plate geometry in a rheometer. Effect of processing variables (temperature, sliding velocity, and normal force) on the frictional properties of the prepreg is investigated. Optical microscopy facilitates quantification of the contact area between the prepreg and rigid substrate. Frictional sliding behavior transitions from mixed to hydrodynamic lubrication regime of a Stribeck curve. Frictional forces are controlled by both adhesive forces and applied load, leading to deviations from Amontons' law.