Prediction of in-situ strength of thermoplastic composite laminate by simulation of the automated tape laying process using PAMFORM

Fiber-reinforced polymer composites are attractive structural materials due to their high specific strength/stiffness and excellent corrosion resistance. However, the lack of through-thickness reinforcement in laminated composites creates inherent susceptibility to fiber-matrix debonding, i.e., interlaminar delamination. This internal damage mode has proven difficult to detect and nearly impossible to repair via conventional methods, and therefore, remains a significant factor limiting the reliability of composite laminates in lightweight structures. Thus, novel approaches for mitigation (e.g., self-healing) of this incessant damage mode are of tremendous interest. Self-healing strategies involving sequestration of reactive liquids, i.e. microcapsule and microvascular systems, show promise for the extending service- life of laminated composites. However, limited heal cycles, long reaction times (hours/days), and variable stability of chemical agents under changing environmental conditions remain formidable research challenges. Intrinsic self- healing approaches that utilize reversible bonds in the host material circumvent many of these limitations and offer the potential for unlimited heal cycles. Here we detail the development of an intrinsic self-healing woven composite laminate based on thermally-induced dynamic bond re-association of 3D-printed polymer interlayers. In contrast to prior work, self-repair of the laminate occurs in situ and below the glass-transition temperature of the epoxy matrix, and maintains >85% of the elastic modulus during healing. This new platform has been deployed in both glass and carbon-fiber composites, demonstrating application versatility. Remarkably, up to 20 rapid (minute-scale) self-healing cycles have been achieved with healing efficiencies hovering 100% of the interlayer toughened (4-5x) composite laminate. This latest self-healing advancement exhibits unprecedented potential for perpetual in-service repair along with material multi-functionality (e.g., deicing ability) to meet modern application demands.

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EFFECT OF MOULDING PRESSURE ON INTERFACIAL CONDITION OF THERMOPLASTIC COMPOSITE LAMINATE MADE OF CO-WOVEN FABRICS

Interfacial Phenomena in Composite Materials '91 ◽

10.1016/b978-0-7506-0356-0.50074-5 ◽

1991 ◽

pp. 269-270

Author(s):

Tsuneo Hirai ◽

Tsutao Katayama ◽

Shimpei Ito ◽

Masahiro Shinohara ◽

Masayoshi Ogawa

Keyword(s):

Composite Laminate ◽

Woven Fabrics ◽

Thermoplastic Composite ◽

Interfacial Condition ◽

Moulding Pressure

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Advanced Thermoplastic Composite Manufacturing by In-Situ Consolidation: A Review

Journal of Composites Science ◽

10.3390/jcs4040149 ◽

2020 ◽

Vol 4 (4) ◽

pp. 149

Author(s):

Isabel Martin ◽

Diego Saenz del Castillo ◽

Antonio Fernandez ◽

Alfredo Güemes

Keyword(s):

Composite Materials ◽

Manufacturing Process ◽

Industrial Process ◽

Thermoplastic Composite ◽

High Deposition Rate ◽

Intimate Contact ◽

Thermoset Composites ◽

Spatial Gradients ◽

Laser Focusing

This article provides an overview of the evolution of the in-situ consolidation (ISC) process over time. This evolution is intimately linked with the advancements in each of the steps of the ISC manufacturing process, is additive in nature, and is limited by the orthotropic nature of composite materials and the physicochemical behavior of the thermoplastic matrix. This review covers four key topics: (a) Thermal models—simulation tools are critical to understand a process with such large spatial gradients and fast changes. Heating systems once marked a turning point in the development of industrial ISC systems. Today, lasers are the most recent trend, and there are three key issues being studied: The absorption of energy of light by the material, the laser profile, and the laser focusing. Several approaches have been proposed for the distributed temperature measurements, given the strong temperature gradients. (b) Adhesion—this refers to two subsequent mechanisms. In the first place, the process of intimate contact is one by which two surfaces of thermoplastic pre-impregnated composite materials are brought into contact under pressure and temperature. This enables closure of the existing gaps between the two microscopic irregular surfaces. This process is then followed by the healing or diffusion of polymer molecules across the interface. (c) Crystallinity—mostly influenced by the cooling rate, and strongly affects the mechanical properties. (d) Degradation—this refers to the potential irreversible changes in the polymer structure caused by the high temperatures required for the process. Degradation can be avoided through adequate control of the process parameters. The end goal of the ISC manufacturing process is to achieve a high product quality with a high deposition rate through an industrial process competitive with the current manufacturing process for thermoset composites.

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