Showing papers on "Composite laminates published in 2020"
TL;DR: In this article, the authors reviewed recently published research into fiber reinforced polymer matrix composites formed using thin-ply laminates and showed that composites with thin-plastic laminations are of interest to aerospace and other high-performance industries.
94 citations
TL;DR: In this paper, a review of composite material failure modes and fracture analysis for aircraft accidents is presented, highlighting the significance of the understanding of composite materials failure modes on the overall aircraft accident investigation process.
73 citations
TL;DR: A novel approach for damage characterization through machine learning is presented where theoretical knowledge of failure and strain-softening is linked to the macroscopic response of quasi-isotropic composite laminates in over-height compact tension tests, demonstrating the effectiveness of machine learning to reduce experimental efforts forDamage characterization in composites.
67 citations
TL;DR: In this paper, a uniformly aligned polyethersulfone (PES) fiber web was designed and fabricated by the melt-spinning PES yarns, which was adopted as an interleave to simultaneously improve both mode I and mode II fracture toughness of the carbon fiber/epoxy composite, addressing the issue of transforming the thermoplastic component into a well controlled uniform and ordered phase structure without being influenced by the liquid forming process.
Abstract: In this work, a uniformly aligned polyethersulfone (PES) fiber web was designed and fabricated by the melt-spinning PES yarns. Such fiber web was adopted as an interleave to simultaneously improve both mode I and mode II fracture toughness of the carbon fiber/epoxy composite, addressing the issue of transforming the thermoplastic component into a well-controlled uniform and ordered phase structure without being influenced by the liquid forming process. The dissolution behaviors of the PES filaments in the epoxy resin were studied by the optical microscopy with a hot stage. The results indicated that the PES filaments were not dissolvable at the temperature of the resin infusion process, but could be dissolved during the curing process of the epoxy resin in a well controllable way and period. Both the mode I and mode II interlaminar fracture toughness of the composites were investigated as a function of areal densities of the PES fiber webs (7.3, 14.7, 21.2 and 28.3 gsm) carefully. A maximum enhancement up to 120% and 68.8% on mode I and II fracture toughness, respectively was obtained with the introduction of the 28.3 gsm-PES fiber web compared to the laminates without interleaves. Analysis of the fracture surfaces of the laminates elucidated that the distinctive improvement of the interlaminar fracture toughness could be attributed to the characteristic interlaminar structures induced from the phase separation of PES in epoxy resin. Moreover, the interleaved laminates displayed an increase of 18.2% and 43.8% for the interlaminar shear strength (ILLS) and compression-after-impact (CAI) properties, respectably. The tensile and flexural properties of the composite were thereafter explored which indicated slightly enhancement on the strengths.
64 citations
TL;DR: In this article, the authors proposed a framework for identifying defects in composite materials by integrating a thermography test with a deep learning technique, which was validated by testing it on composite specimens produced by resin transfer molding and thermoplastic injection molding, using a combination of carbon/organo fabrics and thermoset/thermoplastic resins.
63 citations
TL;DR: In this article, a numerical and experimental investigation on unnotched and open-hole tensile characteristics of fiber-steered variable-axial composite laminates was conducted, where the fiber path was obtained from an optimization framework considering manufacturing characteristics of the Tailored Fiber Placement (TFP) process.
63 citations
TL;DR: In this paper, the effect of ply thickness scaling on several aspects of the mechanical response of composite laminates is reviewed, and the current state-of-the-art and recent developments in manufacturing, design and application of thin plies on novel engineered composite Laminates are presented.
Abstract: The introduction of the spread-tow thin-ply technology enabled the development of composite plies as thin as 0.020 mm. The availability of composite plies with a broader thickness range makes the understanding of the effects of ply thickness more pertinent than ever, therefore, a comprehensive literature review is presented in this paper. The micro-structural effects of ply thickness and ply uniformity on the mechanical response of unidirectional laminae is described. Then, the effect of ply thickness scaling on several aspects of the mechanical response of composite laminates is reviewed. Finally, the current state-of-art and recent developments in manufacturing, design and application of thin plies on novel engineered composite laminates are presented. This review demonstrates that thin plies not only bring improvements to the plain strengths and design flexibility of composite laminates, but can also enhance the performance of primary structural applications, namely those driven by residual strength and damage tolerance requirements. This can be achieved by either combining thin plies with existing material technologies, or through novel design principles. Moreover, it is shown that thin plies provide increased flexibility for multifunctional optimisation and for adoption of more efficient manufacturing technologies, with great potential gains in terms of weight savings and cost reduction during conceptual and detailed design and operation.
61 citations
TL;DR: In this paper, a physical-based three-linear CZM superposed by two bilinear CZMs was proposed to represent two different phenomena including the quasi-brittle matrix fracture characterized by a higher peak stress and a shorter critical opening displacement.
57 citations
TL;DR: In this article, the authors investigated the dynamic mechanical responses and damage development of cross-ply composite laminates under repeated low-velocity impact through finite element simulations with ABAQUS/Explicit.
Abstract: The dynamic mechanical responses and damage development of cross-ply composite laminates under repeated low-velocity impact are investigated through finite element simulations with ABAQUS/Explicit. A progressive damage model for laminates, consisting of the continuum damage model, the 3D Hashin failure criterion and the damage evolution model based on equivalent displacement, is integrated with the bilinear traction-separation relationship cohesive model to simulate the damage initiation, evolution and propagation behavior of different damage modes in composite laminates. Compared with the experimental results, the established finite element model was validated through the global mechanical response and damage distribution contous. Besides, a mesh refinement study was performed by using three different element sizes. The validated model was adopted to investigate the repeated impact behaviors of composite laminates under three different energies. The qualitative conclusions about the effects of repeated impact on global mechanical response were summarized by the changes of impact force, displacement, contact time and energy absorption. Moreover, the effects of repeated impact on the damage characteristics and expansions of matrix and delamination were discussed in detail.
50 citations
TL;DR: In this paper, a review of fiber metal laminates (FMLs) with a focus on hybrid titanium composite laminate (HTCLs) is presented, which are high performance hybrid structures based on alternating stacked arrangements of fiber-reinforced polymer composite (FRPC) plies and metal alloy sheets.
Abstract: This paper reviews fiber metal laminates (FMLs) with a focus on hybrid titanium composite laminates (HTCLs). FMLs are high-performance hybrid structures based on alternating stacked arrangements of fiber-reinforced polymer composite (FRPC) plies and metal alloy sheets. The mechanical performance potential of FMLs inspired an investigation into new composites, metals, and adhesive systems to further improve their mechanical properties and to reduce the weight of these structures. HTCLs offer better advantages when compared to traditional FMLs and FRPCs, especially in aeronautical, marine, military, and offshore applications both at room and elevated temperatures as well as harsh environmental conditions. They are outstanding in terms of stiffness, yield stress, fatigue, and high-velocity impact properties; however, there are some challenges regarding fabrication, surface treatment, and mechanical properties of such structures, which need to be further addressed. Due to the lack of consolidated research surrounding HTCLs, a review is necessary for effective comparison.
50 citations
TL;DR: In this paper, the authors present an experimental study on residual flexural strength of impacted carbon-aramid/Epoxy hybrid composite laminates and show that the damage is locally concentrated at the impacted face and the upper part of the aramid plies core.
TL;DR: In this paper, the effect of composite laminates with different stacking sequences of woven carbon and glass fiber layers in hybrid configurations was investigated. And the performance of the stacking sequence and hybridization on the flexural properties and impact damage mechanisms were widely studied.
TL;DR: In this paper, a coupled thermo-mechanical model is proposed to investigate stiffness degradations of composite laminates and failure strength of fiber reinforced composites in the presence of ambient temperature variations.
TL;DR: In this paper, the repeated low velocity impact responses and damage accumulation mechanism in the composite laminates were investigated by considering the effect of impactor diameter, and the delamination projected area was measured using ultrasonic C-scan during the whole-process repeated impacts.
TL;DR: In this article, the authors investigated the effect of reinforcement induced by carbon nanotubes (CNTs) on the interlaminar cracks in unidirectional 0° laminates.
TL;DR: In this article, the effect of hybrid composites for improvement in mechanical properties and their suitability for different applications was studied and the hybridization of composites is one of the most efficient ways of enhancing the mechanical properties of composite material laminates.
TL;DR: It is shown that the new energy concept provides a significantly larger safe limit of yield for MD composite structures compared to UD criteria, in which the accumulation of energy dissipated due to all damage modes is less than 5% of the fracture energy required for the structural rupture.
Abstract: Composite structures are made of multidirectional (MD) fiber-reinforced polymer (FRP) composite laminates, which fail due to multiple damages in matrix, interface, and fiber constituents at different scales. The yield point of a unidirectional FRP composite is assumed as the lamina strength limit representing the damage initiation phenomena, while yielding of MD composites in structural applications are not quantified due to the complexity of the sequence of damage evolutions in different laminas dependent on their angle and specification. This paper proposes a new method to identify the yield point of MD composite structures based on the evolution of the damage dissipation energy (DDE). Such a characteristic evolution curve is computed using a validated finite element model with a mesoscale damage-based constitutive model that accounts for different matrix and fiber failure modes in angle lamina. The yield point of composite structures is identified to correspond to a 5% increase in the initial slope of the DDE evolution curve. The yield points of three antisymmetric MD FRP composite structures under flexural loading conditions are established based on Hashin unidirectional (UD) criteria and the energy-based criterion. It is shown that the new energy concept provides a significantly larger safe limit of yield for MD composite structures compared to UD criteria, in which the accumulation of energy dissipated due to all damage modes is less than 5% of the fracture energy required for the structural rupture.
TL;DR: In this article, a self-healing composite laminate with improved transverse strength and cyclic healing capabilities was developed to address the problem of impact induced delamination in fiber-reinforced composite laminates.
Abstract: Owing to their unique and outstanding in-plane properties and high specific strength and stiffness, fiber-reinforced polymer composite laminates are being used widely for many structural applications, such as aircrafts, infrastructure, and automobiles. Notwithstanding, they are normally susceptible and vulnerable to damage from out-of-plane impact events. Low velocity impact of fiber-reinforced composite laminates often results in damages that are invisible, but would progressively propagate and later results in a catastrophic failure. This study focused on developing a self-healing composite laminate with improved transverse strength and cyclic healing capabilities that would address the problem of delamination. A novel self-healable and recyclable vitrimer-based shape memory polymer (VSMP) was used as the matrix, unidirectional Saertex glass fiber as the reinforcing fibers, and tension programmed shape memory alloy (SMA) wires (Flexinol) as z-pins. This design followed the strategy of close-then-heal (CTH) for delamination healing. Low velocity impact tests, compression after impact tests, and self-healing of impact induced delamination were investigated. The tension programmed SMA z-pins helped resist delamination during impact; the shape memory effect of the vitrimer and SMA z-pins, together with the external pressure used, helped narrow/close the delamination through constrained shape recovery during heating, so that the narrowed/closed delamination can be healed repeatedly by the VSMP itself. The novel hybrid composite laminate provides a promising sustainable multifunctional material system for structural application.
TL;DR: In this paper, an efficient element-free meshless modeling framework for variable stiffness composite laminates with cutouts is developed, which can provide accurate stress computations and stable nonlinear behavior modeling.
TL;DR: In this paper, the effect of the stacking sequence of hybrid laminates on the 3D void formation through a statistical approach was assessed by using a three-dimensional microstructure created from multiple two-dimensional microscopy images.
Abstract: This work aims at assessing the effect of the stacking sequence of hybrid laminates on the 3D void formation through a statistical approach For that purpose, a three-dimensional microstructure is created from multiple two-dimensional microscopy images Weibull approach shows a poorer fit for carbon fiber composite, while the presence of glass fiber creates homogenization in porosity variation, also treated by ANOVA The present methodology enables the prediction of void volume fraction in different carbon/glass preform ratios and stacking sequence along the laminate length and through-thickness The low glass fiber ratio decreases the void content, homogenized porosity distribution along laminate length, and thickness, mainly for glass fiber preforms located in the middle of the laminate These results confirm that the uniformity of void content throughout the composite can be improved by altering the stacking sequence and ratio of glass to carbon fiber preforms This methodology can be extended to any composite manufacturing process
TL;DR: In this paper, a crack phase-field approach for anisotropic continua fracture of fiber-reinforced matrix composites is presented, in particular, fracture of unidirectional fiber reinforced composite laminates.
Abstract: This study presents a crack phase-field approach for anisotropic continua to model, in particular, fracture of fiber-reinforced matrix composites. Starting with the variational formulation of the multi-field problem of fracture in terms of the deformation and the crack phase fields, the governing equations feature the evolution of the anisotropic crack phase-field and the balance of linear momentum, presented for finite and small strains. A recently proposed energy-based anisotropic failure criterion is incorporated into the model with a constitutive threshold function regulating the crack initiation in regard to the matrix and the fibers in a superposed framework. Representative numerical examples are shown for the crack initiation and propagation in unidirectional fiber-reinforced polymer composites under Mode-I, Mode-II and mixed-mode bending. Model parameters are obtained by fitting to sets of experimental data. The associated finite element results are able to capture anisotropic crack initiation and growth in unidirectional fiber-reinforced composite laminates.
TL;DR: In this article, the properties of flax/basalt/E-glass fibers reinforced epoxy composites were studied and the vacuum bagging technique was adopted for the fabrication of hybrid composite laminates.
Abstract: Mechanical properties of flax/basalt/E-glass fibers reinforced epoxy composites were studied in this paper. Vacuum bagging technique was adopted for the fabrication of hybrid composite laminates. T...
TL;DR: In this article, the effect of temperature on the impact behavior and pseudo-ductile behavior of carbon/glass hybrid composite (CGHC) laminates was investigated, and failure mechanisms were examined using optical microscope to determine the influence of these damage growth on DI of the composites under different temperatures.
TL;DR: In this article, the effect of stacking sequence on tensile and flexural properties of carbon-glass/epoxy hybrid composite laminates is reported, and the composite laminate with glass fabric at the exterior showed interface decohesion as major failure mechanism.
TL;DR: The multiple sparse Bayesian learning (M-SBL) strategy is employed for damage imaging and results from the experiment in composite laminates demonstrate the effectiveness of the proposed method.
Abstract: Lamb wave techniques have been widely used for structural health monitoring (SHM) and nondestructive testing (NDT). To deal with dispersive and multimodal problems of Lamb wave signals, many signal processing methods have been developed. A spatially distributed array of piezoelectric transducers is generally adopted for both transmission and reception of Lamb waves. When imaging the damage in composite laminates, it is necessary to meet the need of processing array signals with high efficiency. In this paper, the multiple sparse Bayesian learning (M-SBL) strategy is employed for damage imaging. Multiple residual signals including damage-reflection waves are decomposed into a sparse matrix of location-based components simultaneously. An appropriate dictionary is designed to match the damage-reflection waves instead of interference waves. The key to success is to obtain the sparse matrix of weighting coefficients through the M-SBL algorithm. Damage imaging can be achieved efficiently using the delay-and-sum (DAS) method with sparse coefficients in time-domain. Results from the experiment in composite laminates demonstrate the effectiveness of the proposed method.
TL;DR: In this article, the effect of interface bonding between AL and CFRP layers on flexural behavior of the multi-material hybrid system was studied by developing three different types of specimens.
Abstract: Hybrid Composite laminates have been widely regarded as a family of highly damage tolerant materials with a high weight-saving potential. The main hindrance to full utilization of Hybrid Composite System in the automotive industry is their structural response as compared to monolithic materials like Steel or Aluminum (AL). The main goal of this research is to investigate the stiffness, weight savings, load-carrying capacity, failure Modes of Al/carbon fiber reinforced polymer (CRFP) hybrid composite system and validate the experimental results with computational Model. The multi-material hybrid composite system comprises of single hat section aluminum material adhesively bonded to woven carbon fiber plies by curing them under temperature and pressure. The effect of interface bonding between AL and CFRP layers on flexural behavior of the multi-material hybrid system was studied by developing three different types of specimens. The first category of specimens was manufactured by using epoxy from the prepreg only to provide adhesion between constituents, second ones were developed by using externally applied an extra layer of epoxy between AL-CFRP layers and finally the third type of samples utilizes 3 M adhesive tape to bond the CFRP and Aluminum sheet. The failure modes of these distinct specimens are studied under flexural loading. The effect of metal volume fraction (MVF) on the failure modes of the hybrid composite beam was also studied. It was found that the failure mode changes from rupture in the load-carrying area to gradual deformation as we increase the metal volume fraction in these hybrid composite specimens. Calculations were performed for the weight savings for these hybrid systems with respect to reference aluminum material having the same thickness as that of the multi-material hybrid system. Weight saving of 15–25% is documented for the multi-material hybrid system as compared to the weight of reference Aluminum material system. Stiffness and progressive damage failure result obtained from experimental three-point bending test are validated with the use of LSDYNA Finite Element Analysis (FEA) for specimens using the only epoxy from the prepreg to provide adhesion between constituents and for samples using externally applied an extra layer of epoxy between AL-CFRP layers for adhesion. Explicit finite element results were found in good agreement with the experimental results.
TL;DR: In this paper, a three-dimensional finite element model of composite laminates for progressive damage analysis has been established based on continuum damage mechanics, which contains four kinds of damage modes of composite laminate under three dimensional stress states, which include matrix damage, fiber breakage, delamination and fiber pull-out.
TL;DR: Results show that copper clad laminates prepared with modified polyphenylene ether (MPPE)/SEBS and LT ceramic fillers have strong competitiveness to fabricate printed circuit boards (PCBs) for high-frequency and high-speed applications.
Abstract: Copper clad laminates (CCLs) with low dissipation factor (Df) are urgently needed in the fields of high-frequency communications devices A novel resin matrix of modified poly (2,6-dimethyl-1,4-phenylene ether) (MPPE) and styrene-ethylene/butylene-styrene (SEBS) was employed in the fabrication of high-frequency copper clad laminates (CCLs) The composites were reinforced by E-glass fabrics, which were modified with phenyltriethoxysilane (PhTES) The composite laminates obtained exhibited impressive dielectric loss of 00027 at 10 GHz when the weight ratio of MPPE to SEBS was 5:1 In order to modify the dielectric constant (Dk), coefficient of thermal expansion (CTE) and other performances of laminates, Li2TiO3 (LT) ceramic powders were introduced into the resin matrix The composite laminates showed low dielectric loss of 00026 at 10 GHz and relatively high flexural strength of 125 MPa when the mass ratio of LT fillers to resin is 04 Moreover, the composite laminates all maintain low water uptake (<05%) The microstructure and thermal properties of composite laminates filled with LT ceramic powders were also tested These results show that copper clad laminates prepared with modified polyphenylene ether (MPPE)/SEBS and LT ceramic fillers have strong competitiveness to fabricate printed circuit boards (PCBs) for high-frequency and high-speed applications
TL;DR: In this article, the ability of ultrasonic and electronic speckle pattern interferometry to analyse the low-velocity impact internal damage mechanisms on basalt composite laminates was investigated.
Abstract: This paper aims to investigate the ability of ultrasonic and electronic speckle pattern interferometry to analyse the low-velocity impact internal damage mechanisms on basalt composite laminates an...
TL;DR: In this article, a micromechanical model is used to investigate ply thickness effect on damage evolution of thin-ply carbon fiber reinforced laminate under transverse tensile load, and the results show that decreasing 90° lamina thickness alters damage progression mechanism and suppresses cracking within matrix loading.