Title: Feasibility of Amorphous Bonding in Thermoplastic Composites and the Resulting Interlaminar Residual Stresses

Authors: Joseph Kirchhoff, Tyler B. Hudson, Mehran Tehrani

DOI: 10.33599/nasampe/s.25.0078

Abstract: During rapid processing of thermoplastic composites, such as automated fiber placement manufacturing, crystallization is suspected to limit full polymer healing on the interfaces. Reptation theory suggests that interdiffusion can persist until temperature falls below the glass transition temperature in amorphous polymers; however, studies indicate that a critical crystallization value hinders interdiffusion for semi-crystalline polymers. This motivates the incorporation of a thin (5-20 m) polyetherimide layer between low-melting polyaryletherketone interfaces. This paper will share results of vacuum bag-only processing fabricated short beam strength samples with varied thermal histories. Specifically, this work investigates the feasibility of processing the amorphous interfaces below the melt temperature of the semi-crystalline layer to prevent crystal melting during processing. It also examines the theoretical development of residual stresses, based on classical laminate theory, arising from mismatches in the coefficient of thermal expansion between the two polymers. In conclusion, this paper presents a novel approach to thermoplastic composite processing that could facilitate high-rate manufacturing and also sheds light on mechanics of failure in such samples.

References: [1] Poe, C. C., Jr., Dexter, H. B. and Raju, I. S., A Review of the NASA Textile Composites Research, AIAA, 1997. [2] Delbrey, J., Database of Mechanical Properties of Textile Composites, NASA Contractor Repot 4747, Aug. 1996. [3] Dow, M. B. and Dexter, H. B., Development of Stitched, Braided and Woven Composites in the ACT Program and at Langley Research Center (1985 to 1997), NASA/TP-97-206234, Nov. 1997. [4] Seneviratne, W., Design and Analysis Methodology for Two-Dimensional Biaxially Braided Composites, MS Thesis, Wichita State University, Wichita, Kansas, 2000. [5] Seneviratne, W. and Tomblin, J., “Adaptation of the Iosipescu In-plane Shear Test Method for High Strength Textile Composites,” Journal of Composites Technology and Research, Vol. 23(4), Oct. 2001. [6] Branscomb, D. and Cole, T., Proving Realistic Simulation for Composites Overbraiding: The Impact of Guide Ring Diameter on Fiber Angles, CAMX 2015, Dallas, TX. [7] Naik, Rajiv A., TEXCAD-Textile Composites Analysis for Design, Version 1.0 User’s Manual, NASA CR 4639, Dec. 1994. [8] Seneviratne, W. and Tomblin, J., Design of a Braided Composite Structure with a Tapered Cross-Section, SAMPE, May 2002. [9] Tomblin, S., Seneviratne, W., and Ng, Y., AGATE - Material Qualification Methodology for 2X2 Biaxially Braided RTM Composite Material Systems, AGATE-WP3.3-033048116, October 2001. [10] Tomblin, S., Seneviratne, W., McKenna, J., and Ng, Y., B – Basis Design Allowables for 2X2 Biaxially Braided RTM Composite Material Systems, AGATEWP3.3-033048-117, NASA Langley, Hampton, VA, September 2001. [11] Tomblin, J. and Seneviratne, W., Carbon Tri-axial Braid Material Qualification, NIAR-Industry-State (NIS) Document #04-004, June 2004.

Conference: SAMPE 2025

Publication Date: 2025/05/19

SKU: TP25-0000000078

Pages: 13

Price: $26.00