Performance of microwave formed angle ply composites

In this progressing and ever advancing world of growing industries which are in awe of improved methodologies for manufacturing of composites in turns demands the methods to be necessarily cheaper and faster. The traditional method of Autoclave curing (Thermal curing), although being expensive, is still the most accepted because it gives least standard deviation during all mechanical tests as compared to other available methods like the use of Ultraviolet and gamma rays heating. Significant research has been done to reduce the manufacturing cycle by using the microwave curing which utilizes the volumetric heating being favorable for composite curing. The microwave curing has been the recent topic of research because of its electromagnetic property which leads to limited wastage of energy.Master of Science (Aerospace Engineering

Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System

For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented.Published versio

Multiscale polymer composites : a review of the interlaminar fracture toughness improvement

Composite materials are prone to delamination as they are weaker in the thickness direction. Carbon nanotubes (CNTs) are introduced as a multiscale reinforcement into the fiber reinforced polymer composites to suppress the delamination phenomenon. This review paper presents the detailed progress made by the scientific and research community to-date in improving the Mode I and Mode II interlaminar fracture toughness (ILFT) by various methodologies including the effect of multiscale reinforcement. Methods of measuring the Mode I and Mode II fracture toughness of the composites along with the solutions to improve them are presented. The use of different methodologies and approaches along with their performance in enhancing the fracture toughness of the composites is summarized. The current state of polymer-fiber-nanotube composites and their future perspective are also deliberated.Published versio

Recent Advances on the Design Automation for Performance-Optimized Fiber Reinforced Polymer Composite Components

Advanced manufacturing techniques, such as automated fiber placement and additive manufacturing enables the fabrication of fiber-reinforced polymer composite components with customized material and structural configurations. In order to take advantage of this customizability, the design process for fiber-reinforced polymer composite components needs to be improved. Machine learning methods have been identified as potential techniques capable of handling the complexity of the design problem. In this review, the applications of machine learning methods in various aspects of structural component design are discussed. They include studies on microstructure-based material design, applications of machine learning models in stress analysis, and topology optimization of fiber-reinforced polymer composites. A design automation framework for performance-optimized fiber-reinforced polymer composite components is also proposed. The proposed framework aims to provide a comprehensive and efficient approach for the design and optimization of fiber-reinforced polymer composite components. The challenges in building the models required for the proposed framework are also discussed briefly

Investigation on ultrasonic welding attributes of novel carbon/elium® composites

Joining large and complex polymer-matrix composite structures is becoming increasingly important in industries such as automobiles, aerospace, sports, wind turbines, and others. Ultrasonic welding is an ultra-fast joining process and also provides excellent joint quality as a cost-effective alternative to other joining processes. This research aims at investigating the welding characteristics of novel methyl methacrylate Elium®, a liquid thermoplastic resin. Elium® is the first of its kind of thermoplastic resin, which is curable at room temperature and is suitable for mass production processes. The welding characteristics of Elium® composites were investigated by optimizing the welding parameters with specially designed integrated energy directors (ED) and manufactured using the Resin transfer molding process. The results showed a 23% higher lap shear strength for ultrasonically welded composite joints when compared to the adhesively bonded joints. The optimized welding time for the ultrasonic welded joint was found to be 1.5 s whereas it was 10 min for the adhesively bonded joint. Fractographic analysis showed the significant plastic deformation and shear cusps formation on the fractured surface, which are typical characteristics for strong interfacial bonding.Nanyang Technological UniversityPublished versionThis research was funded by Nanyang Technological University, Singapore and ARKEMA, Franceunder RCA-18/46 and RIE2020 Advanced Manufacturing and Engineering (AME) domain—Industry AlignmentFund—Pre-positioning polymer matrix composites program

Effect of fixation stitches on out-of-plane response of textile non-crimp fabric composites

Non-crimp fabrics are fabric tapes stitched to an adjacent orthogonal fabric with no associated crimp. In the current research, the effect of fixation polyester stitches in improving through-the-thickness properties of non-crimp fabric composite laminates is investigated. Detailed experimental studies on interlaminar fracture toughness and static indentation properties of stitched and unstitched thin ply carbon fibre epoxy composites have been conducted. About 23% higher peak load and 37% higher energy absorption were noticed during static indentation tests for the stitched ply composites. A detailed SEM investigation has shown that the stitch-stitch interaction ‘within a bi-angle ply’ and ‘between the bi-angle ply’ plays a significant role in reducing the delamination extent. The critical energy release rate during Mode I fracture toughness of stitched composites was found to be 26.5% higher and SEM investigation depicted that the stitches promote the intra-laminar delamination and enhance the toughness of the composite.Nanyang Technological UniversityThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors would like to acknowledge the financial support from Institute for Sports Research, Nanyang Technological University, Singapore and CHOMARAT, France and ARKEMA, France

Fatigue response of ultrasonically welded carbon/Elium® thermoplastic composites

Current research aims at investigating the fatigue strength of ultrasonically welded composite joints with novel liquid acrylic thermoplastic Elium®. Fatigue response of the welded joints with integrated Energy Director (ED) and flat Elium® film was investigated and the baseline comparison was carried out with control adhesives. The results showed 10–12% higher fatigue life at 105 and 106 fatigue cycle as compared to the adhesively bonded joints. Fractographic investigation of fractured welded joints showed features such as fibre impingement and shear cusps formation which contributed to strong interfacial adhesion.Nanyang Technological UniversityThis research was funded by Nanyang Technological University, Singapore and ARKEMA, France under RCA-18/46 and RIE2020 Advanced Manufacturing and Engineering (AME) domain–Industry Alignment Fund–Pre-positioning polymer matrix composites program

Flexural characteristics of novel carbon methylmethacrylate composites

Reactive thermoplastic matrices are widely used for polymer composites manufacturing owing to their ease of processing using cost-effective liquid injection processes. The novel methyl methacrylate (MMA) Elium ® resin is a liquid thermoplastic resin, first of its kind which is curable at room temperature. It has attracted wide interest as a competitive solution to epoxy-based composites for structural applications. In this work, the flexural performances of novel non-crimp carbon fabric (NCCF) Elium ® composite laminates are evaluated. The baseline comparison is done with conventionally used composites with epoxy resin. The stress-strain curve, the fracture failure mechanisms and the effect of the annealing stage have been discussed.Nanyang Technological UniversityAuthors would like to acknowledge the financial support from the Institute for Sports Research, Nanyang Technological University, Singapore, Arkema, France and CHOMARAT, France