Carbon Fiber Reinforced Plastic Composites Research Articles

Analytical model for revealing tool wear law during edge trimming of Carbon Fiber Reinforced Plastics composites

Analytical model for revealing tool wear law during edge trimming of Carbon Fiber Reinforced Plastics composites

Dual-Modal Fusion PRI-SWT Model for Eddy Current Detection of Cracks, Delamination, and Impact Damage in Carbon Fiber-Reinforced Plastic Materials

Carbon fiber-reinforced plastic (CFRP) composites are prone to damage during both manufacturing and operational phases, making the classification and identification of defects critical for maintaining structural integrity. This paper presents a novel dual-modal feature classification approach for the eddy current detection of CFRP defects, utilizing a Parallel Real–Imaginary/Swin Transformer (PRI-SWT) model. Built using the Transformer architecture, the PRI-SWT model effectively integrates the real and imaginary components of sinusoidal voltage signals, demonstrating a significant performance improvement over traditional classification methods such as Support Vector Machine (SVM) and Vision Transformer (ViT). The proposed model achieved a classification accuracy exceeding 95%, highlighting its superior capability in terms of addressing the complexities of defect detection. Furthermore, the influence of key factors—including the real–imaginary fusion layer, the number of layers, the window shift size, and the model’s scale—on the classification performance of the PRI-SWT model was systematically evaluated.

Dynamic compressive impact behavior of CFRP composite under high strain rate loading

Carbon Fiber Reinforced Plastics (CFRP) composite exhibits significant sensitivity to strain rate. In this work, authors investigated the CFRP composite’s dynamic compressive impact behavior under a high strain rate. The vacuum bagging technique was used to fabricate the composite specimens to reduce the presence of voids. Compressive mechanical behavior was examined for the CFRP composite for strain rate ranging from 1384 to 1953 s−1 using a Split Hopkinson Pressure Bar (SHPB) test setup. The experiment aims to investigate the effect of strain rate on stresses, strains, failure strengths, fracture energies, and failure of quasi-isotropic CFRP composites. Furthermore, the specimens’ strength initially increases and achieves its maximum strength, followed by a decrease in strength value. Moreover, an optical microscopic examination reveals that damage in composite laminate grows as the strain rate increases.

Structural digital Twin for damage detection of CFRP composites using meta transfer Learning-based approach

Using deep learning approaches to identify and locate defects in composite structures made of Carbon Fiber Reinforced Plastics (CFRP) is becoming increasingly popular. However, when the training data is limited, the existing deep learning methods do not work well. Moreover, the lack of data for damaged conditions of CFRP structures causes a severe data imbalance, which makes this problem even harder. In this paper, we present a novel damage detection method called DFMTR which stands for Digital Twin based Few-shot Meta Transfer Learning. It creates numerical model as the digital twin to generate a large amount of virtual data under different damage conditions for model training. Then, it applies relational network and domain adaptive techniques to achieve effective few-shot transfer. That means, it can detect damage accurately with only a very small amount of real data. This is very useful and practical for damage detection of high-end CFRP equipment. In experiments, our approach outperforms existing methods in all commonly used metrics. The classification accuracy can be improved to more than 82% from 55% by using only 4 real samples, and the accurate localization of damaged area is also successfully achieved.

Prediction of tool wear and surface finish using ANFIS modelling during turning of Carbon Fiber Reinforced Plastic (CFRP) composites

Carbon fiber-reinforced plastics (CFRP) are widely used in various industries due to their high strength to weight ratio, corrosion resistance, durability, and excellent thermo-mechanical properties. The machining of CFRP composites has always been a challenge for the manufacturers. In this study, CNC turning operation with coated carbide tool is used to machine a specific CFRP and the relationship between the cutting parameters (Speed, Feed, Depth of Cut) and response parameters (Vibration, Surface Finish, Cutting Force and Tool Wear) are investigated. An adaptive-network-based fuzzy inference system (ANFIS) model with two multi-input–single-output (MISO) system has been developed to predict the tool wear and surface finish. Speed, feed, depth of cut, vibration and cutting force have been used as input parameters and tool wear and surface finish have been used as output parameters. Three sets of cutting parameter have been used to gather the data points for continuous turning of CFRP composite. The model merged fuzzy inference modeling with artificial neural network learning abilities, and a set of rules is constructed directly from experimental data. This model is capable of predicting the cutting tool wear and surface finish during turning of CFRP composite. The predicted tool wear and surface finish data are compared to the experimental results. The predicted data agreed well with the actual experimental data with 98.96 % accuracy for tool wear and 99.61 % accuracy for surface finish.

Investigation of the effect of symmetrical hybrid stacking on drilling machinability of unidirectional CFRP, GFRP and hybrid composites: Drilling tests and damage analysis

Fiber-reinforced plastics are undoubtedly superior to metals in many sectors due to their advantageous properties. Especially carbon fiber reinforced plastics (CFRP) and glass fiber reinforced plastics (GFRP) are widely used in industry. Although CFRP offers higher strength, its use is limited due to its high cost. However, with hybridisation, it is possible to produce composites that will provide sufficient strength at lower cost. The mechanical behaviour of hybrid composites may be different compared to glass or carbon composites, as well as the damage behaviour during machining. In this study, the influence of hybrid stacking in drilling hybrid composites was investigated. The results showed the hybrid stacking, especially the position of the carbon plate, has a significant impact on the force generation and damage formation in the drilling. Although stacking the carbon layer at bottom caused an increase in thrust forces, it reduced the damage formation at the hole exit.

Performance-tunable thermal barrier coating for carbon fiber-reinforced plastic composites via flame spraying

Thermal barrier coatings (TBCs) are essential for improving the heat resistance of materials operating in high-temperature environments. This paper proposes a new method for manufacturing double-layered TBC with graded porosity for carbon fiber-reinforced plastic (CFRP) composites. The TBC was created by a flame spraying process, consisting of relatively dense and porous layers: (1) a dense layer was produced by spraying yttria-stabilized zirconia (YSZ) particles directly onto neat carbon fabric substrate and (2) a porous layer was prepared by co-spraying YSZ particles with sacrificial polyetheretherketone (PEEK) particles. The porosity of the porous layer was controlled by varying a PEEK injection distance (D) and a PEEK feed rate (R). The correlation between porosity and thermal conductivity of the TBC layer was investigated to assess its thermal barrier performance. The TBC fabricated with the D = 5 cm and the R = 1.0 g/min offered the optimal porosity and conductivity. The 640μm-thick TBC with 34% porosity and 0.27 W/m·K thermal conductivity protected the CFRP substrate remarkably under the subjected torch at 500°C, as the TBC layer reduced the surface temperature of CFRP to 230°C. Thermomechanical analysis, following thermal shock tests, revealed that the double-layered TBC/CFRP composite retained 87% and 75% of its pristine flexural strength and modulus, respectively, while the neat CFRP composite was completely burnt out. This study explored the application of flame spray technology to develop highly effective double-layered TBCs with tunable porosity to maximize their thermal barrier performances. All results from the current study provide new insights into the design and development of TBC and CFRP composites, which will benefit a wide range of lightweight high-temperature applications.

Experimental and numerical investigation on detection of BVID in CFRP composite plates using vibro-acoustic modulation

ABSTRACT Carbon fibre reinforced plastic (CFRP) composite has gained popularity due to the advantages such as its high strength-to-weight ratio and high corrosion resistance, but susceptibility to barely visible impact damage limits their use in engineering. This study experimentally and numerically investigates the detection of BVID in CFRP composite plates using Vibro-acoustic modulation (VAM) technique. An experimental system of VAM was constructed for measuring sidebands induced by the nonlinear effects of BVID. An integrated finite element (FE) model is developed to further explore the nonlinear interaction between the BVID, low-frequency pump, and high-frequency probe waves. To address this issue of the mesh size and computational time step mismatch caused by the large difference in frequency between the pump and probe waves, a regionally refined mesh was employed at the BVID region. Furthermore, the effects of BVID’s size and depth on the modulation were discussed. Through the Hilbert-Huang Transform (HHT), the amplitude modulation (AM) and frequency modulation (FM) indexes were extracted from the VAM responses to quantitatively characterise the impact damages. The results demonstrate that the MIA index increases steadily with the exciting voltage and damage degree, making it a suitable indicator to accurately assess the impact damage in CFRP composites.

Influence of Fibre Orientation on the Slotting Quality of CFRP Composites Using the Multi-Tooth Mill.

Carbon fibre-reinforced plastic (CFRP) composites, prized for their exceptional properties, often encounter surface quality issues during slotting due to their inherent heterogeneity. This paper tackles CFRP slotting challenges by employing multi-tooth mills in experiments with various fibre orientations and tool feed rates. In-plane scratching tests are performed under linearly varying loads; then, slotting experiments are conducted at different parameters. The scratching test results indicate that the fibre orientation and cutting angles have significant influences on forces and fracture process. The slotting experiments demonstrate that cutting forces and surface roughness Sa of the bottom slotting surface are notably affected by the fibre orientation, with disparities between up-milling and down-milling sides. Reorganising Sa data by local fibre cutting angle θ highlights consistent Sa variations between up-milling and down-milling sides for 0° ≤ θ ≤ 90°, with lower Sa on the up-milling side. However, for 90° < θ ≤ 150°, Sa variations diverge, with lower Sa on the down-milling side. Unexpectedly, Sa on the down-milling side decreases with increasing θ in this range. Additionally, the tool feed rate exerts a more pronounced influence on Sa on the up-milling side.

Investigation of Fiber Orientation of Fused Filament Fabricated CFRP Composites via an External Magnetic Field

Abstract For carbon fiber-reinforced plastic (CFRP) composites, controlling the interior fiber distribution and orientation during the manufacturing process is a common approach to optize the structural performance of fabricated parts. However, few studies have been conducted to investigate fiber alignment during the additive manufacturing of CFRP composites. This study proposes a magnetic field controlled (MFC) method to control the fiber orientation during the fused filament fabrication (FFF) of nickel-coated carbon fiber (NCF) reinforced polymer composites. Firstly, a theoretical analysis model is established to explore the suitable magnetic field intensity for fiber rotation. Secondly, a customized FFF system with MFC components is implemented, and a polylactic acid matrix composite containing 10 wt% NCF is printed to validate the feasibility of the proposed approach. The microstructure of the printed samples is examined to assess the effectiveness of the method. Finally, uniaxial tensile tests are performed to investigate the impact of fiber orientation adjustment on mechanical properties. The experimental results reveal that the MFC method can effectively align the interior fiber orientation of CFRP composites, leading to a significant increase in the tensile strength (approximately 8.8%) and Young's modulus (around 10.5%) of the printed samples.

Barely visible impact damage detection in CFRP composite using vibrothermography with narrowband sweep excitation

The extensive use of carbon fiber-reinforced plastic (CFRP) composite materials in various industries has posed new challenges for conducting effective structural health monitoring and nondestructive evaluation techniques. Based on local defect resonance (LDR), the vibrothermography with narrowband sweep excitation is proposed to detect BVIDs in the CFRP composite. The response spectrum of displacement at the impact crater was collected by a laser Doppler vibrometer, which was used to determine the frequency range of narrowband sweep excitation. The frequency range was further validated by the analysis of local defect resonance for thermal responses, and the sweep duration was also optimized. Subsequently, the proposed vibrothermography was employed to detect BVIDs with varying severity. The impact damage could be efficiently activated and a significant temperature rise was generated in the defective areas, which enhances the temperature contrast of the thermal images and facilitates the quantification of defects.

Tensile strength prediction of unidirectional polyacrylonitrile (PAN)-based carbon fiber reinforced plastic composites considering stress distribution around fiber break points

Recent advancements in enhancing the mechanical characteristics of carbon fibers open up new application possibilities for carbon fibre-reinforced plastic (CFRP) composites. Particularly in unidirectional CFRPs, which form the basal structure of CFRP laminates, developing a micromechanics model capable of predicting the tensile strength of unidirectional CFRPs based on carbon fiber mechanical characteristics is a current aspiration. This study conducted a stress distribution analysis around the fiber fracture point to predict the tensile strengths of unidirectional CFRPs prepared with five types of polyacrylonitrile (PAN)-based carbon fibers, each with unique mechanical characteristics. Numerical simulation results obtained using a unidirectional CFRP model that considered the stress concentration, fiber axial stress, and bimodal Weibull distribution were reasonably consistent with the experimental results for the tensile strengths of unidirectional CFRP composites, regardless of the differences in the mechanical characteristics of the fiber. Our findings can provide guidance for designing further enhanced high-performance CFRP materials.

Multi optimization in slot milling of CFRP composites through grey relational- based Taguchi analysis

Carbon fiber-reinforced plastic (CFRP) composite materials are challenging to machine due to their anisotropy and heterogeneity. Thus, the experimental study of milling CFRP composite material is very crucial. In the current study, based on Taguchi’s L9 orthogonal array, slot milling experiments were performed on CFRP composite samples to make a decision on a parametric optimization of multiple responses such as material removal rate (MRR), delamination factor (Fd) and surface roughness (Ra) using grey relational-based Taguchi analysis. The selected milling parameters are cutting speed (A), feed (B), and depth of cut (C). Based on Grey Relational Grade (GRG), Analysis of Variance (ANOVA) was used to determine the parameters' significant contributions and the parameters' optimal levels. The results showed, with a 95% confidence level, that all of the chosen cutting parameters have a substantial impact on all of the measured responses. Based on a confirmatory test performed under ideal milling conditions, MRR has been increased with an improvement of 31.25 %, Fd has been decreased with an improvement of 1.66% and Ra has been decreased with an improvement of 28.3%. These improvements in all measured responses are equivalent to an improvement of GRG by 3%.

High Strain Rate Modeling of CFRP Composite Under Compressive Loading

An in-depth understanding of how carbon fiber-reinforced plastics (CFRP) respond to intense strain rates is essential, particularly in non-linear deformation and dynamic loading situations. The researchers undertook a computational study to examine the behavior of CFRP composites when exposed to high strain rates under compressive loading. Specifically, they employed Split Hopkinson Pressure Bar models for cohesive interfacial simulations, continuum shell analysis, and laminated composites oriented at 0° at a strain rate equivalent to 900 s-1. The Finite Element model utilized a custom Hashin damage model and a vectorized user material (VUMAT) sub-routine to identify degradation damage within the CFRP composite model. The quasi-isotropic composite demonstrated a significant enhancement in dynamic strength compared to static values, attributed to its intense sensitivity to strain. As confirmed by experimental test results, numerical simulations accurately predicted stress (σ)-strain (ε) and strain rate (ἐ) curves. Additionally, it was observed that the relationship between damage behavior varied depending on the element type used.

Effect of temperature and moisture composite environments on the mechanical properties and mechanisms of woven carbon fiber composites

AbstractTemperature and moisture are important environmental conditions governing the usage of carbon fiber‐reinforced plastics (CFRP). In this study, tensile, compression, and shear tests of woven CFRP composites were conducted in four composite environments: cold‐temperature dry state, room‐temperature dry state, elevated‐temperature dry state, and elevated‐temperature wet state. Fourier transform infrared (FTIR) spectroscopy was used to analyze the molecular composition and structure under these environments. The fracture morphology was also analyzed using scanning electron microscopy (SEM) to understand the deterioration mechanism of the material properties at the macro and micro scales. Finally, a two‐parameter Weibull statistical model was used to evaluate the scattering of the composites. The results demonstrate that the tensile, compressive, and shear properties of the material decrease under harsh conditions, and the degradation effect on the ultimate strength is much greater than that of the modulus. Cold‐temperature dry and elevated‐temperature wet conditions are particularly severe. Composite environments significantly affect the macroscopic failure process and ultimate failure mode of materials. In general, the temperature and humidity of the matrix system acts at the core of the deterioration mechanism of composites, affecting the properties of the fiber/matrix and orthogonal woven fiber interfaces, and eventually resulting in a loss of their constitutive strength and bearing capacity. The theoretical ultimate strength were consistent with the experimental values.Highlights Comprehensive mechanical property testing in multiple composite environments. Degradation mechanisms were revealed from multiscale morphology analysis. Scattering of composites were evaluated using statistical analyses. Cold temperature dry and elevated temperature wet were the worst states. Deterioration effect of environment on matrix and interface is the core failure mechanism.

Adaptive Machining Method for Helical Milling of Carbon Fiber-Reinforced Plastic/Titanium Alloy Stacks Based on Interface Identification.

CFRP/Ti stacks composed of carbon fiber-reinforced plastic composites (CFRP) and titanium alloys (Ti) are widely used in aerospace fields. However, in the integrated hole-making process of CFRP/Ti stacks, the machining characteristics of various materials are significantly different, and constant machining parameters cannot simultaneously meet the high-quality machining requirements of two materials. In addition, errors exist between the actual thickness of each material layer and the theoretical value, which causes an impediment to the monitoring of the machining interface and the corresponding adjustment of parameters. An adaptive machining method for the helical milling of CFRP/Ti stacks based on interface identification is proposed in this paper. The machining characteristics of the pneumatic spindle and the interface state in the helical milling of CFRP/Ti stacks are analyzed using self-developed portable helical milling equipment, and a new algorithm for the real-time monitoring of the machining interface position and adaptive adjustment of the machining parameters according to the interface identification result is proposed. Helical milling experiments were carried out, the results show that the proposed method can effectively identify the position of the machining interface with good identification accuracy. Moreover, the proposed parameter-adaptive optimized machining method for CFRP/Ti stacks can significantly improve hole diameter accuracy and machining quality.

Comparative performance evaluation between ta-C and TiAlCrN coated tools during milling of additively manufactured CFRP composite

Due to the excellent strength-to-weight ratio and corrosion resistance properties, the application of carbon fibre-reinforced plastic (CFRP) composites is rising among various industries day-by-day. This research addresses the performance evaluation of tetrahedral amorphous hard carbon (ta-C) and TiAlCrN coated carbide tools during milling of additively manufactured CFRP composite under dry environment. Tool rotational (spindle) speed, feed and depth of cut are considered as the variable factors in order to evaluate the machining performance characteristics in milling operation concerning surface roughness (Ra), cutting force (Fc) and cutting temperature (T). Taguchi's L16 orthogonal array design of experiments was adopted to conduct the machining trials under various settings of process variables. The relative influence of the different types of coatings and different operating parameters on machined surface morphology in milling was analysed by scanning electron microscope. From the experimental results, a promising machining performance is noticed for TiAlCrN coated carbide end milling tool accomplished by physical vapour deposition technique in terms of all machining attributes compared to ta-C coated end milling tool due to superior wear resistance, surface hardness and bonding strength of coating material. Among the tools used, TiAlCrN coated carbide tools for CFRP milling application promises excellent machinability performances in terms of reduced cutting force, enhanced machined surface morphology as well as surface finish, and minimum cutting temperature. The mean value ratios for Ra ta-C/RaTiAlCrN, Fc ta-C/FcTiAlCrN and T ta-C/TTiAlCrN are 1.44, 1.24 and 1.21, respectively.

Effects of Graphene Oxide Nanoparticles on Delamination in CFRP and Optimization Using Response Surface Modeling

AbstractCarbon fiber composites recently have captured the attention of many for their wide array of properties surpassing those of traditional metals. Carbon fiber‐reinforced plastic (CFRP) has several excellent properties like a high strength‐to‐weight ratio, better chemical resistance, and other strength characteristics. But one problem affecting the use of CFRP is its delamination. This occurs during drilling holes for various operations. It is a known fact that the aircraft industry is one such industry very much dependent on such drilling operations. Failures such as fiber rupture, surface irregularities, micro‐crack formation, and deformations around drilling regions are commonly encountered during the machining of CFRP composite. This research has studied the effects of graphene oxide nanoparticles on delamination in the drilling of CFRP composite. Carbon fiber is manufactured using a vacuum bag process. The optimum conditions for the drilling process are found by using response surface modeling (RSM) which leads to minimum delamination in CFRP fabricated.

The effects of support plate thickness on the drilling machinability of CFRP

When carbon fiber reinforced plastics (CFRP) are drilled, delamination damage occurs at the hole entry and exit. An important method to reduce delamination at the hole exit is using a support plate. Therefore, sustainable drilling of CFRP to reduce the delamination damage is promising for modern industries. In this study, the effect of drilling CFRP composite plates using support plates of different thicknesses on thrust force, delamination, and borehole surface quality was experimentally investigated. The results showed that the thrust force increased as the support plate thickness increased at low spindle speed, but the support plate thickness did not significantly affect the thrust force at high spindle speed. While severe delamination damage occurred at the hole exit in the tests without the use of support, delamination damage was significantly reduced in the case of using a support plate. On the other hand, the severity of the damages decreased as the support plate thickness increased, especially unless very high feed rates were chosen. Consequently, the thickness of the support plate considerably influences the damage formation and severeness of the damages is significantly reduced when a support plate with sufficient thickness is used.

Experimental investigations of impact behavior and milling performance of T700-CFRP under cryogenic conditions

The carbon fiber reinforced plastic (CFRP) composite is a reliable body material for modern airplanes, and extremely difficult to cut owing to its complex structure and special mechanical characteristics. In cutting CFRP, fiber breakage and delamination defects very frequently appear on the machined surface. The use of cryogenic cooling in CFRP cutting has proven to be an advanced approach to improving the machined surface quality of CFRP composites. To reveal the mechanism of milling CFRP under cryogenic conditions, this study investigates the impact behavior and cutting performance of T700-CFRP at low temperatures. The impact test of T700-CFRP unidirectional laminates with 0°, 45°, and 90° fiber directions was performed at various temperatures ranging from 20 °C to −196 °C, to analyze the impact toughness and the fracture morphology. Side milling experiments of CFRP laminates of 0°, 45°, and 90° fiber directions with the PCD endmill were conducted at the same temperatures used in the impact test. Experimental findings revealed that for 0° specimens, the impact toughness increased at lower temperatures, and the impact damage worsened as the temperature dropped from −120 °C to −196 °C. There were no evident changes in the impact toughness or impact damage of 45° and 90° specimens with the decrease in temperature. The feed force and radial force increased as the cooling medium temperature lowered during milling CFRP. The machined surface of 45° workpieces was the roughest among all the workpieces and covered with numerous pits and craters. The machined surface roughness Ra of 0° workpieces decreased as the cooling medium temperature was lowered from 20 °C to −160 °C and then increased at −196 °C, while the Ra value of both 45° and 90° workpieces rose as the temperature dropped from 0 °C to −196 °C.