Advanced Composite Manufacturing Research Articles

Determination of the In-Plane Shear Behavior of and Process Influence on Uncured Unidirectional CF/Epoxy Prepreg Using Digital Image Correlation Analysis

The investigation of the in-plane shear behavior of prepreg is crucial for understanding the generation of wrinkles of preforms in advanced composite manufacturing processes, such as automated fiber placement and thermoforming. Despite this significance, there is currently no standardized test method for characterizing uncured unidirectional (UD) prepreg. This paper introduces a ±45° off-axis tensile test designed to assess the in-plane shear behavior of UD carbon fiber-reinforced epoxy prepreg (CF/epoxy). Digital image correlation (DIC) was employed to quantitatively track the strains in three dimensions and the shear angle evolution during the stretching process. The influences of the temperature and stretching rate on the in-plane shear behavior of the prepreg were further investigated. The results reveal that four shear characteristic zones and wrinkling behaviors are clearly distinguished. The actual in-plane shear angle is significantly lower than the theoretical value due to fiber constraints from both the in-plane and out-of-plane aspects. When the off-axis tensile displacement (d) is less than 15.6 mm, the ±45° specimens primarily exhibit macroscale in-plane shear behavior, induced by interlaminar interface shear between the +45° ply and −45° ply at the mesoscale. The shear angle increases linearly with the d. However, when d > 15.6 mm, fiber squeezing and wrinkling begin to occur. When d > 29 mm, the in-plane shear disappears in the completely sheared zone (A). The reduction in the resin viscosity of the CF/epoxy prepreg caused by increased temperature is identified as the primary factor in lowering the in-plane shear force resistance, followed by the effect of the increasing resin curing degree. Higher shear rates can lead to a substantial increase in shear forces, eventually causing cracking failure in the prepreg. The findings demonstrate the feasibility of the test method for predicting and extracting uncured prepreg in-plane shear behaviors and the strain-rate and temperature dependency of the material response.

Improving the interfacial adhesion between recycled carbon fibres and polyphenylene sulphide by bio-inspired dopamine for advanced composites manufacturing

Polyphenylene sulphide composites with recycled carbon fibres are of high interest due to their promising mechanical properties. Poor interface adhesion between recycled carbon fibre and thermoplastic matrix, however, remains a major problem in composite manufacturing. Herein, a novel one-step method using bio-inspired copolymerisation of dopamine to graft silica nanoparticles onto the carbon fibre surface is reported. Comprehensive investigations were conducted to fabricate the treated carbon fibre and characterise the modified samples by analysing the surface morphology and functional groups. The experimental results reveal that the network of bio-inspired adhesive polydopamine and nanoparticles adhering to the fibres can improve inter-laminar shear strength by 28.4% in the resulting composites. In addition, dynamical mechanical analysis results prove that the interfacial bonding at the fibre/matrix interface provides good resistance to thermal cycling. This novel approach introduces the functional groups on the recycled carbon fibre surface, leading to an improvement of surface energy and wettability between the carbon fibres and polyphenylene sulphide matrix and constitutes a robust and green approach to the manufacturing of advanced composites.

Boron Nitride Reinforcement: Revolutionizing Aluminum-Based Composite Manufacturing via Friction Stir Process

The revolutionizing potential of boron nitride (BN) reinforcement in Aluminum-Based Composite Manufacturing via Friction Stir Process (FSP) is showcased in this study. FSP, executed with precision using a vertical milling machine, fabricates composite materials with exceptional properties. The meticulous selection of parameters, including pin diameter, tool tilt angle, and rotation speed, ensures optimal results. AA 2024 substrate undergoes secure affixation, adhering to cleanliness protocols. The SEM image reveals a homogenous dispersion of BN particles, crucial for optimizing mechanical, thermal, and electrical properties.The incorporation of BN via FSP leads to significant enhancements across various mechanical properties. Tensile strength improves by 20.78%, hardness by 34.44%, fatigue strength by 23.83%, and wear resistance by 28.28%. These improvements underscore the efficacy of BN reinforcement through FSP, offering promising prospects for advanced composite manufacturing. The study exemplifies the potential of BN to revolutionize the industry, paving the way for the development of high-performance aluminum composites with superior mechanical characteristics.

Investigating the impacts of processing variability on tool-part interaction for interply-toughened aerospace composites using a novel shear technique

This study aims to investigate uncertainties in tool-part interaction during manufacturing of advanced aerospace composites. To achieve this goal, a custom-built shear test was developed using a Dynamic Mechanical Analyzer (DMA) to directly characterize tool-part interfacial stresses during composites processing. This novel method was used to quantify tool-part stresses during processing of interply-toughened Toray T800S/3900-2B on a steel tool with various conditions, accounting for variables such as the number of release coats on the tool, cure pressure and temperature, laminate layup, and strain rate. The observed trends in results were correlated with tool and part surface microstructures, investigated by laser scanning digital microscopy. This study’s findings underscored that the number of release coats, cure pressure, and temperature significantly influence tool-part interaction due to altered surface conditions and viscoelastic behaviors at the tool-part interface.

Microwave sintering of ZrB2-based ceramics: A review

Recently, microwave sintering has absorbed remarkable attention on the basis of enhanced microstructural/mechanical characteristics in comparison with conventional sintering techniques based on powder technology. This method not only can be employed for the processing of metals, alloys, and metal matrix composites but also for the manufacturing of advanced ceramics and ceramic matrix composites. Zirconium diboride (ZrB2) as an interesting member of ultrahigh temperature ceramics is one of the most undertaking candidates in modern structural ceramics applications. This paper reviews the processing-densification-mechanical properties correlations in microwave-sintered ZrB2-based ceramics and composites. The text concentrates on the microwave-assisted production of ZrB2 divided into two categories: synthesis of ZrB2 powders by microwave sintering and sintering of ZrB2-based ceramics and composites by microwave sintering. The effects of some additives and reinforcements, such as B4C, SiC, TiC, and MgO, on zirconium diboride's densification and mechanical properties are summarized.

State-Of-The-Art of Sandwich Composite Structures: Manufacturing—to—High Performance Applications

This cutting-edge review highlights the fundamentals, design, and manufacturing strategies used for sandwich composites. Sandwich composite structures have the advantages of light weight, high strength, impact resistance, stability, and other superior features for advanced applications. In this regard, different core materials have been used in the sandwich composite structures, such as cellular polymer foam, metallic foam, honeycomb, balsa, tubular, and other core geometries. Among these, honeycomb sandwich composite materials have been effectively applied in space engineering, marine engineering, and construction applications. The foremost manufacturing techniques used for sandwiched composite structures include hand lay-up, press method, prepreg method, vacuum bagging/autoclave, vacuum assisted resin infusion, resin transfer molding, compression molding, pultrusion, three-dimensional (3D) printing, four-dimensional (4D) printing, etc. In advanced composite manufacturing, autoclave processes have been the method of choice for the aerospace industry due to less delamination between plies and easy control of thickness dimensions. Moreover, machining processes used for sandwich composites are discussed in this article. In addition to aerospace, the high-performance significance of sandwiched composite structures is covered mainly in relation to automobile engineering and energy absorption applications. The structure-, fabrication-, and application-related challenges and probable future research directions are also discussed in this article.

A 3-D micromechanical framework to study damage propagation and failure of printed aligned discontinuous fiber-reinforced composites

This paper presents a novel and efficient micromechanical framework for finite element simulation of damage and failure in 3-D printed aligned discontinuous fiber-reinforced composites. The framework can predict the initiation and propagation of different types of damage in the composite under tensile loading along the fibers’ axis. The micromechanical framework includes the microstructural representation of the composite with explicit fibers and matrix in addition to linear expansions at the ends. Accurate constitutive equations are utilized for fibers, matrix, and fiber/matrix interfaces in the microstructural representation. Fibers’ locations and lengths are generated randomly; based on a target distribution for the fibers’ aspect ratios measured experimentally; within the microstructural representation. Optimal microstructural representative dimensions for reliable investigation of the mechanical response are computed by conducting sensitivity analyses. The accuracy of the micromechanical framework is validated versus the experimental results of a 3-D printed aligned discontinuous fiber-reinforced composite as the composite of interest. It is shown that the proposed framework can simulate various aspects of the mechanical response, including the failure pattern and stress-strain behavior. Subsequently, the sensitivity of the mechanical response of the composite to a few constitutive equation-related parameters, including the strength and fracture toughness of the fiber/matrix interfaces and the matrix strength, is investigated. The correlation between the studied parameters and the composite’s strength and failure pattern is also analyzed and discussed. This paper delivers valuable guidance on the mechanical response of printed aligned discontinuous fiber-reinforced composites, eventually resulting in the paradigm-shifting design, manufacturing, and analysis of such advanced composites.

Advanced Composite Manufacturing using Additive Manufacturing and Robotic Techniques

In the realm of mechanical engineering, the adoption and integration of cutting-edge technologies promise unprecedented advancements in material science and production processes. This paper delves into the pioneering realm of Advanced Composite Manufacturing leveraging both Additive Manufacturing (AM) and Robotic Techniques. Exploiting the intrinsic merits of AM, such as enhanced design freedom, reduced lead times, and intricate detailing, the research synergizes these advantages with the precision, speed, and repeatability offered by robotic mechanisms. The culmination of these methods allows for the fabrication of composite structures with unparalleled geometrical intricacy and tailored mechanical properties. Key insights from our exploration involve the optimization of AM parameters for composite materials, robotic path planning for efficient layering, and a holistic technique for integrated process control. Experimental evaluations signify marked improvements in terms of strength-to-weight ratios, production efficiency, and repeatability. Our findings pave the way for a new frontier in composite production, holding significant implications for industries ranging from aerospace to biomedical engineering. This study serves as a foundational step towards a paradigm shift in how we perceive and employ composite manufacturing in a progressively digital age.

Study on Structural Design and Analysis of Composite Boat Hull Manufactured by Resin Infusion Simulation.

In this paper, structural design and analysis of a composite boat hull was performed. A resin transfer molding manufacturing method was adopted for manufacturing the composite boat hull. The RTM process is an advanced composite manufacturing method that allows a much higher quality product than the hand lay-up process, and less manufacturing cost compared to the autoclave method. Therefore, the RTM manufacturing method was adopted. The mechanical properties of the various aramid fibers and polyester resin were investigated. Based on this, structural design of boat hull was performed using aramid fiber or polyester. After structural design, the optimized resin infusion analysis for RTM manufacturing method was performed. Through the resin infusion analysis, it is confirmed that the designed location of resin injection and outlet is acceptable for manufacturing.

Utilization of Antibacterial Nanoparticles in Photocurable Additive Manufacturing of Advanced Composites for Improved Public Health.

This paper presents the additive manufacturing and characterization of nanoparticle-reinforced photocurable resin-based nanocomposites with a potential antimicrobial function for improved public health applications. Two types of photocurable resins are reinforced by titanium dioxide (TiO2) or zinc oxide (ZnO) nanoparticles with average diameters in the 10–30 nm range to provide antimicrobial properties. The developed nanocomposites can be additively manufactured using the digital light processing method with an outstanding surface quality and precise geometrical accuracy. Experimental characterizations are conducted to investigate key mechanical properties of the 3D printed nanocomposites, including Young’s Modulus, tensile strength, and abrasion resistance. Specimens produced were observed to demonstrate the following characteristics during testing. Tensile strength increased by 42.2% at a maximum value of 29.53 MPa. The modulus of elasticity increased by 14.3%, and abrasion resistance increased by 15.8%. The proper dispersion of the nanoparticles within the cured resin is validated by scanning electron images. The wettability and water absorption testing results indicate that the developed nanocomposites have an outstanding water resistance capability. The pairing of digital light processing with these novel nanocomposites allows for the creation of complex composite geometries that are not capable through other manufacturing processes. Therefore, they have the potential for long-term usage to improve general public health with antimicrobial functionality. The pairing of an unmodified photocurable resin with a 1% ZnO concentration demonstrated the most promise for commercial applications.

Two-Stage Sector Partition Path Planning Method for Automated Fiber Placement on Complex Surfaces

Automated fiber placement (AFP) is an advanced composite manufacturing technology which is widely used in the production of complex shaped aircraft components. However, on the surface with large curvature, the fiber compaction performance is poor, and the direction deviation and the geodesic curvature of the path increase sharply with the offset distance, resulting in various placement defects. To solve this problem, the influence of the surface curvature on the path performance is studied, and a two-stage sector partition path planning method for AFP on complex surface is proposed in this paper. The constraints of the direction deviation, turning radius and the compaction state of the fiber are comprehensively considered in this method. By analyzing the compaction feature, the distance between the roller and the surface is used to evaluate the compaction condition and an initial partition criterion is established according to the normal curvature of the surface along the roller axis. Then, the quantitative relationship between path performance and offset distance is derived, and the precise sector is determined under the constraints of placement direction and turning radius. The path performance constraints are fully considered in the path generation process, so the iterative process of evaluation–modification is effectively avoided. Simulations and experiments are then carried out on the winglet surface and the results show that compared with the parallel method, the proposed method can significantly improve the direction deviation, turning radius and compaction quality of the placement paths at the cost of gaps/overlaps. Satisfactory placement paths can be obtained with reasonable constraints on the complex surface.

Multi-level lot-sizing with raw-material perishability, deterioration, and batch ordering: an application of production planning in advanced composite manufacturing

Advanced composite manufacturing processes use polymers and fibers pre-impregnated with thermoplastic or thermoset resins as raw-materials. These highly sensitive materials are considerably perishable, affecting the production process in several ways and requiring special inventory cares. This perishable condition of raw materials in composite manufacturing constitutes the main motivation for this paper. We study a multi-level lot-sizing problem with raw-material perishability and batch-ordering. Several types of perishable raw-material items are procured in batches from suppliers. Once received, two different inventory sub levels are considered: a special storage location where the material can be stored avoiding deterioration, and a secondary location at the shop floor where the material becomes available for production and starts deteriorating. We proposed a mixed-integer programming formulation for the problem and perform computational experiments with sensitivity analyses, demonstrating its potentials for practical applications in planning composite production.

Preface

It is our great pleasure to welcome you to the 2nd International Conference on Mechanical Manufacturing and Industrial Engineering (MMIE2019) held in Beijing, China during December 14-16, 2019 with the workshop, 2019 The 2nd International Conference on Advanced Composite Materials (ICACM 2019). The conference is dedicated to issue related to the areas of advanced composite materials, mechanical manufacturing and industrial engineering.Prof. Alan Lau from Swinburne University of Technology, Australia, Prof. Yong Suk Yang from Pusan National University, Korea, Prof. Lihui Lang from Beihang University, China and Prof. Tingkai Zhao from Northwestern Polytechnical University, China were invited to deliver keynote speeches and provide latest findings in their respective areas of expertise. It was a golden opportunity for the students, researchers and engineers to interact with the experts and specialists to get their advice or consultation.Due to the constraint of the capacity and suitability of the topics, 34 papers were accepted as full papers for publication and presentation from 75 submissions. We would like to express our gratitude and appreciation to the authors for your contributions. Many thanks go as well to all of the reviewers who helped us maintain the high quality of manuscripts included in the Proceedings published by IOP Conference Series: Materials Science and Engineering. We also express our sincere thanks to the members of the organizing team for their hard work. We wish that all the authors and delegates find MMIE2019 interesting, exciting and inspiring. We also wish that our guests will enjoy your stay in Beijing, China at this beautiful time of the year.

Review of automated fibre placement and its prospects for advanced composites

Fibre placement is a research hot spot for the intelligent manufacturing of advanced composites, and the efficiency of fibre placement has become an important index to evaluate the performance and cost of composite products. The traditional fibre placement method is mainly based on fibre winding (FW). However, the quality stability and placement efficiency are both higher in automated fibre placement (AFP) than in FW. Accordingly, a detailed discussion on this issue is provided herein. In this review, the concept and main research areas of AFP are introduced, a comprehensive literature review on the key AFP technologies is presented, and the characteristics for these key technologies are analysed. Then, the current AFP research status in various countries is investigated and compared, and the existing problems and future development trends are noted. Finally, the large-scale application prospects of AFP in high-performance fields (e.g. aerospace) are forecasted, and some new methods and new ideas for improving the performance of fibre placement systems are proposed, including the application of induction welding to enhance the modular function of the placement head device and the comprehensive utilization of 3D printing and topology optimization for composite fibre placement.

Effects of the exposition of an autoclave prepreg to the processing environment on its properties, curing cycle and final composite behavior

One of the major concerns when using prepreg materials for advanced composite manufacturing is the cure advancement. Although this type of prepreg curing is usually programmed to occur at high temperatures, the exposition to environmental conditions during processing, intrinsic to the industrial production, leads to the cure advancement and, consequently, to the detriment of prepreg’s processability. Therefore, techniques that provide accurate, relatively low-cost, and fast alternatives for tracking prepreg out-time are of great interest for composite industries. In this scenario, the present work aims to provide information on the use of thermal and rheological characterization techniques for monitoring the prepreg out-time. To do so, prepreg specimens were aged for pre-established periods (0 to 60 days) and characterized by differential scanning calorimetry (DSC) and dynamic shear rheometry techniques. Also, laminates were manufactured from aged prepregs, and their properties were characterized by ultrasound and volume fraction analyses and by interlaminar shear strength (ILSS) tests. The combination of the findings provides out-time tracking and properties monitoring alternatives for industries and points out to the possibility of extending prepreg out-time limits, reducing the waste on prepreg processing, one of the main challenges associated with composite manufacturing.

PENGARUH FRAKSI VOLUME PENGUAT 2, 2,5 DAN 3% SERAT BAMBU HAUR DAN FIBERGLASS TERHADAP KEKUATAN TARIK MATRIKS POLIESTER

Against the backdrop of the increasing need for quality composite materials and the development of increasingly advanced composite manufacturing technology in the machinery industry. The aim of this research is to develop composite materials with bamboo fiber reinforcement and glass fiber as an alternative to automotive raw materials to replace plastic. Preparation of composite specimens with each reinforcement with volume fractions of 2%, 2.5%, and 3% and specimens without reinforcement or 0% volume fraction as a comparison.
 The polymer material used is Yukalac 157-EX BQTN polyester as its matrix. With haur bamboo fiber and fiberglass as a reinforcement. Making specimens using the hand lay up method. Tests carried out are composite specimen tensile tests. Tensile testing was carried out using the ASTM D 638M-84 M-1 standard.
 Based on the test results, it was concluded that the effect of fiber volume fraction on the characteristics of composite samples for tensile tests. Composite strengthened by haur bamboo and fiberglass powder at 3% heavy volume fraction has the most ideal characteristics that have a tensile strength of 53.581 MPa, modulus of elasticity of 87.452 MPa and polymer composite material with a strength of haur bamboo and fiberglass powder with a length of 5 mm at 3% reinforcing volume fraction can be used as an alternative to automotive raw materials, namely replacing polyoxymethylene plastic materials for the front bumper.

Prediction of temperature-frequency-dependent mechanical properties of composites based on thermoplastic liquid resin reinforced with carbon fibers using artificial neural networks

A considerable interest has been generated in recent years in the use of thermoplastic polymers as matrices in the manufacture of advanced composites that require high reliability during long-term operations. In this research, a new Elium® acrylic matrix developed by Arkema was studied to evaluate the accelerated test methodology based on time-temperature superposition principle of Carbon Fiber/Elium® 150 composites. The results show that the high frequencies increase the glass transition (Tg) to higher values because the free volume is favored by polymer chains movement. In addition, artificial neural network has been used to model the temperature-frequency dependence of dynamic mechanical over the wide range of temperatures and frequencies due to its complex non-linear behavior. It has been observed that low frequencies result in low damping due to the lower internal friction, while high frequencies provide greater stiffness to the chains, resulting in a high damping. The long-term life prediction using master curves confirms that this new material can be considered to acoustic or vibrational damping purposes, considering its use in temperatures above Tg.

Study of the influence of initiator content in the polymerization reaction of a thermoplastic liquid resin for advanced composite manufacturing

AbstractConsiderable interest has been generated in the last years in the use of thermoplastics polymers as matrices in advanced composites manufacturing. In this research, a new Elium® acrylic matrix developed by Arkema has been studied to evaluate the influence of different benzoyl peroxide initiator (Luperox®78) contents on the polymerization reactions for Elium®150. For that, thermal and rheological analyses were performed providing a better understanding of these reactions. The results show that the initiator concentration and temperature affect the resin's properties not only in the initiation step, but also in the resin's complete polymerization reaction. Besides that, it was observed that the initiator concentration can also affect the polymer chain lengths, which may lead to variations in the dynamic mechanical properties and thermal stability of the polymer.

Simulation of vacuum assisted resin transfer molding process through dynamic system analysis

Vacuum assisted resin transfer molding is a promising process in advanced composite manufacturing with a wide range of applications in industry. That potential is often misused, though, because of the lack of an efficient and reliable simulation tool to support product development. Most of the simulation methods in use today are based on Darcy’s law, which explains the permeation of a fluid in a porous medium. However, it is known that this law has limitations when applied to the context of dual-scale fibrous reinforcements: macro porosity given by fiber architecture generates resistance to flow, while the inner porosity inherent to fiber tows causes it to absorb resin, affecting the flow. The latter effect cannot be explained by traditional theory. In order to explore these limitations, this work proposes a simplified model to vacuum assisted resin transfer molding process from the point of view of system dynamics, and to prove the viability of such theory. The ultimate goal is to propose a more complete model in light of system dynamics that saves time and cost while offering the same reliability as current simulation models. In order to provide an explanation to both dual-scale phenomena, a parallel association between a resistance and a fluid capacitance is proposed. Model validation is then performed through the analysis of experimental data followed by the comparison between the Darcy infusion profile and the one predicted by the resistor-capacitor-parallel (RC-parallel) circuit model. Thus, this work is able to perform a proof of concept that leads to a novel and yet unexplored field of study.

Changeover process improvement based on modified SMED method and other process improvement tools application: an improvement project of 5-axis CNC machine operation in advanced composite manufacturing industry

This paper shares a real industry experience for an improvement project of the changeover process through a conventional Single-Minute Exchange Die (SMED) method and other process improvement application tools. This project focuses on the changeover activities for one of the advanced composite manufacturing processes, called trimming process that involves 5-axis CNC machine operation. The cause and effect and five whys analysis techniques and some steps of conventional SMED are applied in this improvement project. Four standard strategies and priorities sequence are introduced for an extension step of conventional SMED. The conceptual decision model is then proposed to present the systematic improvement process carried out in this project. Four specific solutions from the selected strategies are then recommended to be implemented. The current implementation results show that the total changeover time is reduced to 44% and internal type activities time is reduced to 48%. The paper discusses some key success factors and future recommendations of the current project.