Article
Materials Science, Composites
Yujiao Bai, Meiling Yan, Zhonghai Xu, Fan Yang, Jianping Wan, Jun Ma, Wenbo Liu, Rongguo Wang, Xiaodong He
Summary: This study utilized lightweight and high strength CFRP material to produce T-shaped specimens for T-joint. The use of J-272 film as the adhesive improves the initial failure load and toughness of the composite T-joints by enhancing the interfacial binding between the rib web and the skin.
COMPOSITES COMMUNICATIONS
(2023)
Article
Materials Science, Composites
Dong Quan, Han Chen, Long Qin, Jun Lin, Guiwei Dong, Guoqun Zhao
Summary: The investigation of advanced joining techniques for aerospace composites is crucial for ensuring aviation safety and improving production efficiency. This study focuses on using plain-woven PEEK and PPS meshes as joining agents for an aerospace carbon fibre/epoxy laminate through a co-cure process. An atmospheric plasma treatment is applied to the meshes to enhance the chemical bonds and interactions between the meshes and the composite during the co-curing stage. The results show that the joints formed using the plain-woven PEEK/PPS meshes exhibit excellent fracture resistance, especially those cured with PEEK.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Composites
Jiaming Liu, Jia Liu, Dongsheng Yue, Yannan Ma, Mengmeng Han, Dong Quan, Guoqun Zhao
Summary: The co-cure joining of thermoset composites by thermoplastics is an advanced approach to develop robust composite joints. Polyethylenimine (PEI) and Polyetheretherketone (PEEK) polymers were utilized as interlayers for the co-cure joining of an aerospace composite. The insert of PEI and PEEK interlayers significantly enhanced the mix-mode crack resistance of the composite joints.
COMPOSITES COMMUNICATIONS
(2023)
Article
Mechanics
Oguzcan Inal, Kali Babu Katnam, James Taylor, Stephan Sprenger, Prasad Potluri, Constantinos Soutis
Summary: This study focuses on the multiscale toughened co-cured composite interfaces using carbon/epoxy laminates. Three toughening routes are used to enhance the interlaminar fracture energies. The results show that the toughening routes significantly alter the R-curve behaviour and interlaminar fracture energies. The joint tests demonstrate that the toughening routes affect the static failure of the joint configurations and the strength and damage evolution depend on the interlaminar fracture energies.
COMPOSITE STRUCTURES
(2023)
Article
Materials Science, Multidisciplinary
Vinayak S. Hiremath, D. Mallikarjuna Reddy
Summary: The current research examines the impact of bonding angle, bonding width, and adherend thickness on the failure load of flat-joggle-flat (FJF) co-cured composite joints. The primary goal of this work is to use an artificial neural network (ANN) to predict the failure load at the FJF joint. Experimental results revealed that, 8 mm to 12 mm adherend thickness, 25 mm adherend width, and a 10 degrees to 15 degrees bonding angle, gave maximum failure load.
Article
Mechanics
Marco Riva, Alessandro Airoldi, Tommaso Turconi, Pietro Ballarin, Matteo Boiocchi, Luigi Bottasso
Summary: This paper investigates the use of corrugated composite laminates in designing flexible joints that can withstand axial load, transmit torque, and support significant bending deformations. The concept is numerically explored and applied to the design of a heavy-duty flexible joint for rotorcraft. A manufacturing technique for producing axisymmetric corrugated laminates is developed and tested, validating the numerical predictions and confirming the quality of manufacturing. A complete prototype is designed, produced, and tested, demonstrating the ability to withstand design limit loads without damage development.
COMPOSITE STRUCTURES
(2023)
Article
Engineering, Manufacturing
Anil R. Ravindran, Raj B. Ladani, Chun H. Wang, Adrian P. Mouritz
Summary: This study examines the strengthening effects of z-pins on different types of composite step-lap joints. The results reveal that z-pins are highly effective at increasing the ultimate strength and elongation limit of single lap joints. However, they are less effective for quadruple lap joints and do not provide any strengthening for multi-step lap joints.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2022)
Article
Mechanics
Pei He, Weikang Feng, Marko Pavlovic
Summary: This paper presents an innovative bonded joining technology as an alternative to traditional welded connection for steel circular hollow section (CHS). Wrapped composite joints have potential to greatly improve fatigue endurance in multi-membered truss structures. The influence of chemical bonding resistance, fracture toughness of resins, and steel yielding on debonding of wrapped composite joints is characterized. Test results show that higher strength steel and toughened vinyl-ester resin contribute to increased ultimate load and displacement at failure, respectively.
COMPOSITE STRUCTURES
(2023)
Article
Construction & Building Technology
Yalin Liu, Ya Wei, Lei Ma, Linbing Wang
Summary: Ultra-high performance concrete (UHPC) has excellent mechanical properties and durability, making it a promising material for bridge deck overlay or structural member repair. However, the large autogenous shrinkage of UHPC can hinder its application. This study develops a novel internal curing agent, calcined bauxite (CB) aggregate, to effectively reduce the autogenous shrinkage of UHPC and improve its mechanical properties. The results show that IC UHPC with CB aggregate exhibits smaller crack widths and delayed onset of cracking compared to normal UHPC, and the use of fibers further enhances its crack resistance. Normal UHPC overlay experiences more delamination and curling than IC UHPC overlay, and early-age drying has a detrimental effect on the UHPC overlay. Reinforcement in the UHPC layer proves to be effective in reducing shrinkage strain.
CEMENT & CONCRETE COMPOSITES
(2022)
Article
Materials Science, Multidisciplinary
Asif Khan, Heung Soo Kim
Summary: A supervised machine learning framework was proposed for local assessments of delamination and transducer debonding in smart composite laminates using their low-frequency structural vibrations. Load independent discriminative features were identified and linear discriminant analysis outperformed other classifiers. The issue of overfitting was addressed by evaluating the classifier's predictive performance on independent test cases, providing insightful guidelines for the assessment of multidamages in smart composite laminates.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2022)
Article
Engineering, Chemical
Dong Quan, Ujala Farooq, Guoqun Zhao, Clemens Dransfeld, Rene Alderliesten
Summary: This study co-cured thermoplastic films with carbon fiber/epoxy composite joints using a co-curing process, and the results demonstrated that the co-cured joints had better or comparable structure integrity and fatigue resistance compared to the joints bonded by aerospace adhesives.
INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES
(2022)
Article
Engineering, Chemical
Dharun Vadugappatty Srinivasan, Sridhar Idapalapati
Summary: This study measured the temperature-dependent properties of a modified epoxy film adhesive and studied its bonding performance at different temperatures, generating a debonding map and identifying the debonding region between 1.17T(g) and 1.33T-g.
JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY
(2021)
Review
Materials Science, Composites
Pietro Sabbadin, Christian Berggreen, Brian Nyvang Legarth, Lujin Lin
Summary: This study presents a novel test fixture for analyzing the fracture characteristics of delaminations in monolithic laminates and face-core debonds in foam core composite sandwich specimens. The results show stable crack growth in monolithic laminate specimens and highly non-linear response in sandwich specimens before crack propagation, prompting further analysis and inspection to identify the source of this behavior.
JOURNAL OF COMPOSITE MATERIALS
(2021)
Article
Mechanics
Weikang Feng, Pei He, Marko Pavlovic
Summary: This paper proposes a combination of 3D Digital Image Correlation (DIC) technique and FE analysis as a method for monitoring debonding crack propagation at a complex composite-to-steel interface. The fatigue tests show that the fatigue performance of wrapped composite joints is superior to their welded counterparts.
COMPOSITE STRUCTURES
(2022)
Article
Chemistry, Physical
Felipe Vannucchi de Camargo, Eduardo da Silva Fernandes, Carla Schwengber ten Caten, Annelise Kopp Alves, Carlos Perez Bergmann, Giangiacomo Minak
Summary: The study introduces the analysis of single-lap co-cured joints of thermoplastic self-reinforced composites made with reprocessed LDPE and UHMWPE fibers, along with a micromechanical analysis of its constituents. Optimal processing conditions were found to yield joints with 6.88 MPa of shear strength, with shear failure generally preceded by debonding-induced longitudinal cracks due to accumulated stress. This composite material shows promise for wider industrial applications due to its specific mechanical properties, progressive damage of joints, and recyclability.
Review
Materials Science, Composites
Janos Plocher, Lorenzo Mencattelli, Federico Narducci, Silvestre Pinho
Summary: Recent studies have shown that replicating structures and toughening mechanisms found in flora and fauna can help create high-performance fiber-reinforced polymers with enhanced toughness and damage tolerance. Understanding the design principles and mechanisms is crucial in manufacturing damage-tolerant bio-inspired composites.
COMPOSITES SCIENCE AND TECHNOLOGY
(2021)
Article
Mechanics
C. Breite, A. Melnikov, A. Turon, A. B. de Morais, C. Le Bourlot, E. Maire, E. Schoberl, F. Otero, F. Mesquita, I Sinclair, J. Costa, J. A. Mayugo, J. M. Guerrero, L. Gorbatikh, L. N. McCartney, M. Hajikazemi, M. Mehdikhani, M. N. Mavrogordato, P. P. Camanho, R. Tavares, S. M. Spearing, S. Lomov, S. Pimenta, W. Van Paepegem, Y. Swolfs
Summary: This study experimentally validated blind predictions of six state-of-the-art models on the longitudinal tensile failure of unidirectional fibre-reinforced composites. It was found that models without major conservative assumptions regarding stress redistributions around fibre breaks tend to overestimate failure strains and strengths, while models with at least one such assumption showed better agreement for these properties. The study also revealed that all models failed to accurately predict the development of fibre break (and cluster).
COMPOSITE STRUCTURES
(2022)
Article
Mechanics
Joao M. Machado, Joao Manuel R. S. M. Trvares, Pedro P. Camanho, Nuno Correia
Summary: This study proposes a machine-learning approach based on a convolutional neural network architecture to automatically parse the void content of optical microscopy images without parameter tuning. Experimental results show that this approach accurately parses void content from microscopy images, outperforming traditional thresholding algorithms.
COMPOSITE STRUCTURES
(2022)
Article
Mechanics
Igor A. Rodrigues Lopes, Pedro P. Camanho, Francisco M. Andrade Pires, Albertino Arteiro
Summary: An invariant-based constitutive model for unidirectional composites, including viscous effects in the elastic and plastic regimes at finite strains, is proposed. The model utilizes a multiplicative decomposition of the deformation gradient and an isoclinic configuration to avoid intermediate configuration non-uniqueness. It incorporates visco-elastic behavior through the generalised Maxwell model, with a transversely isotropic yield function and a non-associative plastic potential. Visco-plastic effects are introduced through the Perzyna overstress function. The performance of two algorithms for implicit integration is compared, with the semi-implicit stress update algorithm being faster and the fully implicit stress update algorithm guaranteeing quadratic convergence rate in the Newton-Raphson scheme. The model accurately predicts stress-strain responses for different fiber orientation angles and captures fiber re-orientation due to external loading.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Mechanics
Fujian Zhuang, Albertino Arteiro, Rodrigo P. Tavares, Pedro P. Camanho, Puhui Chen
Summary: This paper presents the development and validation of a mesoscale numerical model to predict the bearing failure of composite laminates reinforced by unidirectional continuous fibers, focusing on specimens that show a significant non-linear response prior to failure. Thorough analyses and comparisons of the experimental and numerical results show a good correlation of the bearing strengths and overall deformation, as well as good agreement in terms of damage size and damage shape. Relevant limitations include difficulties in predicting the post-peak plateau stresses and the loading displacements in some configurations, setting the stage for additional future research.
COMPOSITE STRUCTURES
(2022)
Article
Mechanics
Bing Yan, Mingbo Tong, C. Furtado, Federico Danzi, A. Arteiro, Song Pan, Xiong Pan, Pedro P. Camanho
Summary: This article introduces an Improved Semi-analytical Method (ISM) as a quick design tool for predicting and optimizing the strength of composite scarf repair structures. It proves the feasibility of applying this method and shows its accuracy in predicting the tensile strength of scarf repair structures.
COMPOSITE STRUCTURES
(2023)
Article
Engineering, Manufacturing
I. R. Cozar, F. Otero, P. Maimi, E. Gonzalez, S. Miot, A. Turon, P. P. Camanho
Summary: A new 3D elastoplastic damage model is proposed to predict the plastic deformation and progressive failure of composite materials. The model is validated through various tests and shows good agreement with experimental data.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2022)
Article
Multidisciplinary Sciences
B. Yu, T. J. Katafiasz, S. Nguyen, G. Allegri, J. Finlayson, E. S. Greenhalgh, S. T. Pinho, S. Pimenta
Summary: This study aims to quantify and model the statistical distribution of fibre pull-out lengths formed on the translaminar fracture surface of composites for the first time. X-ray computed tomography is used to measure the extent of fibre pull-out, and the relationship between pull-out length distributions, micromechanical properties, and the translaminar fracture toughness is established.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Mechanics
Federico Danzi, Pedro J. Silva Campos, Albertino Arteiro, Denis Dalli, Carolina Furtado, Jeremy Chevalier, Rodrigo P. Tavares, Frederic Lani, Pedro P. Camanho
Summary: This paper presents a study on the longitudinal fracture toughness of thermoplastic-based composite materials. It explores the relationship between size-effect laws and crack resistance curves using double-edge notched (DEN) specimens. The study also features the use of SEM and fractographic images to capture the main failure mechanisms, as well as CT scanning to observe early stages of crack propagation. Overall, this investigation provides a qualitative and quantitative analysis of characteristic intra-laminar failure mechanisms in thermoplastic composites.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Mechanics
Anatoli Mitrou, Albertino Arteiro, Jose Reinoso, Pedro P. Camanho
Summary: In this study, an equivalent single layer approach using the Phase Field method is developed to model fracture events in multidirectional balanced thin-ply laminates. The anisotropic nature of the laminates is accounted for by introducing a structural tensor based on scaled directional vectors. The scaling constants are defined using the laminate lay-up and intra-laminar fracture toughness, reducing the number of input parameters and providing a new perspective on their definition. The proposed formulation is implemented using an anisotropic conductivity matrix in Abaqus, simplifying the simulations. Experimental results are successfully reproduced, validating the model for size effects and off-axis loading responses.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Torquato Garulli, Tomas J. Katafiasz, Emile S. Greenhalgh, Silvestre T. Pinho
Summary: In this work, a bio-inspired microstructural concept is designed and manufactured to enhance the longitudinal compressive performance of multidirectional carbon fiber reinforced polymer (CFRP) laminates. Taking inspiration from layered materials found in nature, such as the anchoring spicula of the deep-sea glass sponge Monoraphis chuni, the authors created various design concepts and developed a strategy to reproduce the characteristic alternation of stiff and soft regions observed in the natural material. The proposed microstructure showed significant improvements in failure load and ligament specific stress at failure compared to a baseline laminate, suggesting its potential for lightweight structure design subjected to compression loading.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
M. Erfan Kazemi, Victor Medeau, Emile Greenhalgh, Paul Robinson, James Finlayson, Silvestre T. Pinho
Summary: This study proposes a novel design methodology using bio-inspired and interleaved layups to develop hybrid carbon fibre-reinforced polymer composite structures for improved high-velocity impact performance. The results show that the new design significantly improves energy dissipation and activates additional failure mechanisms compared to traditional layups.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Adam D. Whitehouse, Victor Medeau, Lorenzo Mencattelli, Bamber Blackman, Silvestre T. Pinho
Summary: This study develops a novel profiling concept to improve the mechanical performance of adhesive joints between metallic adherends and composite substrates. The experiments show that profiling the edge of the metallic adherend can increase the peak load by at least 27% and improve the stability of failure. Further experiments demonstrate that increasing the profile parameters can achieve significant mechanical performance gains. Acoustic emission monitoring data shows that profiling results in failure initiation occurring at higher loads, suggesting better stress distributions and lower peak stresses. Fracture surface analysis reveals that profiling deflects the translaminar fracture path and enhances damage tolerance through a debonding mechanism at the profile tips.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Materials Science, Composites
M. Erfan Kazemi, Victor Medeau, Lorenzo Mencattelli, Emile Greenhalgh, Paul Robinson, James Finlayson, Silvestre T. Pinho
Summary: We introduce novel zone-based hybrid laminate concepts to enhance the high-velocity impact (HVI) response of baseline carbon fibre-reinforced polymer (CFRP) composites. By keeping approximately 80% of the baseline CFRP mass in the hybrid concepts, similar areal weights and substantial in-plane mechanical properties are maintained. Three zones are identified along the laminate thickness, and tailored materials are incorporated to improve the HVI response. Various materials, including carbon (thin- and thick-plies), glass, Zylon, ultra-high molecular weight polyethylene (UHMWPE), shape memory alloy/carbon fabric, and ceramic, alumina, and titanium sheets, are studied. All laminate concepts have comparable areal weights for meaningful comparison. Experimental results demonstrate up to 95% improvement in energy dissipation compared to the baseline quasi-isotropic (QI) CFRP configuration.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Manufacturing
Masahito Ueda, Yuki Suzuki, Silvestre T. Pinho
Summary: The analytical method for calculating the axial compressive stress-strain relationship of a unidirectional carbon fiber-reinforced plastic (UD CFRP) was presented, taking into account the variability of the fiber misalignment angle. It was found that the load-bearing capabilities of different fiber groups decreased significantly with greater misalignment angles. Fibers with a misalignment angle of 0.5 degrees showed a large load drop after reaching their maximum loading, leading to ultimate failure.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2023)
