Title: Forming Limits of TuFF Composites in Stretch Forming Processes

Authors: Thomas A. Cender, Henry Fidlow, Shridhar Yarlagadda, Dirk Heider, Pavel Simacek, Suresh G. Advani, John W. Gillespie Jr.

DOI: 10.33599/nasampe/s.22.0763

Abstract: Tailored universal Feedstock for Forming (TuFF) is an aligned discontinuous fiber composite material which is able to achieve 60% fiber volume fraction and aerospace equivalent properties due to its high degree of fiber alignment. One advantage of the discontinuous fiber format is that TuFF composites can stretch form biaxially to produce complex geometry parts, which cannot otherwise be produced with continuous fiber reinforcement. Ply extensibility in the fiber direction is governed by the relative longitudinal displacement of neighboring short fibers. An important feature in understanding the formability of an aligned discontinuous fiber composite, is the effect of strain on the composite microstructure and the resulting structural performance. In this work, the microstructure of thermoplastic TuFF composites is analyzed with X-ray micro-CT to determine the evolving microstructural changes with increasing magnitude of strain. In-situ Digital Image Correlation, is used to visualize localizing defects which lead to the onset of material tearing. DIC can be used to determine abrupt material failures which occur at high strain rates. At low strain rates the microstructure evolution with applied strain is more gradual and statistical in nature and microscopy (optical or X-ray micro-CT) is more suitable to quantify these changes.

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Conference: SAMPE 2022

Publication Date: 2022/05/23

SKU: TP22-0000000763

Pages: 12

Price: $24.00