Reinforced Aluminum Laminates Research Articles

Strengthening the bonding interfaces of carbon reinforced aluminum laminate by slot structure

AbstractA reliable strategy to enhance the bonding ability in carbon reinforced aluminum laminates (CARALL) is proposed, which is based on the mechanical interlocking effect generated by the surface slot structure of aluminum alloy enhances the structural interface between fibers/resins and aluminum alloy. The characteristic of slot structure is determined, and the strengthening mechanism of bonding interfaces is revealed. The CARALL samples with slot structure are fabricated via an hot pressing process. The micro texture morphologies, mechanical, interlayer bonding properties under different conditions are studied. The results indicate that forming a slot structure on the aluminum surface is beneficial for improving the interfacial bonding performance. Compared with the non‐slotted structure, the interlayer type II fracture toughness of the slotted structure is increased by 112.99%. The slotted structure can reduce the defects at the interface between the layers and improve the interface bonding force. In this work, the interlaminar shear strength (ILSS) of the slotted structure sample was 27.08% higher than that of the non‐slotted structure sample.Highlights A slotted structure was proposed to solve the problem of insufficient bonding strength. A slotted structure consistent with the direction of adjacent fibers is designed. The interlayer type II fracture toughness of the slotted structure is increased by 112.99%. The final crack propagation of the slotted structure sample is reduced by 40%. The final failure area of the slotted structure sample is reduced by 53.85%.

Enhancing carbon fiber reinforced aluminum laminates with cellulose paper interlayers: experimental characterization of tensile, flexural, and interlaminar fracture toughness

ABSTRACT The mechanical properties of fiber metal laminates (FML) are influenced by several various factors. Interface adhesion plays a particularly crucial role in interlaminar strength. Enhancing the interlaminar strength of carbon fiber reinforced aluminum laminate (CARALL) composites present a persistent challenge due to inherent weaknesses between metal and composite elements. Therefore, this study focuses on improving the interlaminar performance of CARALL composites by introducing cellulose paper interlayer at the metal/composite interface. The cellulose paper interlayer offers the advantage of being cost-effective and sustainable. Cellulose paper-interleaved CARALL composites were fabricated by vacuum bagging method and exhibited noteworthy improvements in mechanical properties. Comparative analysis with pristine samples revealed substantial enhancements, including a 15% increase in tensile strength, a remarkable 42% improvement in flexural strength, and a significant enhancement in mode-I fracture toughness by 65%. Furthermore, the cellulose paper interleaving played a crucial role in stabilizing fracture formation at the fiber-matrix interface, with mode II fracture toughness witnessing a 3% increase. Visual examination revealed the underlying toughening processes occurring in the interfacial area. This innovative approach of interleaving laminated composites with cellulose paper emerges as a sustainable and effective strategy, demonstrating the potential to fortify and toughen the interlaminar zones of CARALL composites.

Analysis of the thermal expansion coefficient of glass- and carbon-fibre-reinforced composites

With the development of manufacturing processes, an increase in the importance of metal-fibre composites in materials engineering is observed. These are materials consisting of appropriately arranged layers of metal and various types of fibres. The very wide use of composite materials in the construction of machine and equipment components means they are often exposed to work in variable temperature conditions. The aim of this article was analysis of the thermal expansion of typical composites: carbon fibre-reinforced polymer, glass fibre-reinforced polymer, glass-reinforced aluminium laminate and carbon-fibre reinforced aluminium laminate. EN AW-6060 aluminium alloy was used as the reference material. The aim of the dilatometric tests was to determine the coefficient of thermal expansion and the dimensional stability of composite materials at elevated temperatures up to 100 °C. The EN AW-6060 aluminium alloy was characterized by the highest linear expansion coefficient (20.27×10−6 1/K). Composites containing glass fibres were characterized by the lowest positive linear thermal expansion coefficient. Among the composite materials tested, CARALLs exhibit the lowest thermal expansion coefficient.

Study on bending properties and damage mechanism of carbon fiber reinforced aluminum laminates

Study on bending properties and damage mechanism of carbon fiber reinforced aluminum laminates

MECHANICAL BEHAVIOUR OF CARBON AND JUTE FIBERS REINFORCED ALUMINIUM LAMINATES FABRICATED IN DIFFERENT STACKING SEQUENCES

In this research work, the mechanical properties of aluminium laminates having carbon fiber reinforcement and carbon-jute fibers reinforced aluminium laminates fabricated in different stacking sequences are studied. Here the fiber metal laminates are manufactured through the hand layup technique. A compression moulding machine was used to press the laminates during the production process. In this study, carbon and jute fibers along with thin aluminium sheets are used as reinforcement. Four different stacking sequences were selected. Each arrangement is symmetric and consists of ten layers of reinforcements. The fabricated laminates were subjected to tensile, compressive, flexural, hardness and impact tests. The test results show that the laminate L2 with outermost layers of carbon fibers revealed the highest tensile strength of 268 MPa, followed by L4 laminate with jute fibers outer layers having a tensile strength of 226 MPa. Whereas, the laminates L1 and L3 with outer layers of aluminium sheets show improved flexural and impact strength along with high hardness value. The flexural strengths are 246 MPa and 204 MPa respectively. Impact strength of 36 MPa, 32 MPa and hardness value of 64 HVN and 62 HVN respectively.

Identifying the contributions of constituents to the fracture performance and failure mechanism of fiber metal laminate

AbstractFiber metal laminate (FML) is a damage‐tolerant material that has gained special attention in the aircraft industry. To clarify the confusing contributions of constituents to the quasi‐static fracture performance and failure mechanism, six kinds of glass fiber reinforced aluminum laminates (Glare) were designed. Quasi‐static fracture tests were carried out to examine their crack resistance, stable crack extension, and residual strength. Moreover, postmortem characterizations were performed to reveal the macro and micro failure morphologies. It was found that the glass fiber reinforced polymer (GFRP) layers can positively contribute to Glare's quasi‐static fracture performance due to its in‐situ quasi‐brittle but not completely brittle fracture characteristics, which was shown by the special plateau formed on P–Δa curve of Glare, and by the improved crack resistance, longer critical crack length, and higher residual strength in Glare with higher content of GFRP. However, the enhancement achieved by increasing the volume fraction of GFRP was not as effective as by increasing the aluminum thickness, since thickening aluminum in a limited range could increase the fracture toughness and promote the delamination and fiber pull‐outs in Glare. To further identify the effect of the properties of the metal layer, a titanium‐reinforced Glare was designed and tested. It was found to transform the fracture process to be titanium dominant, which delayed the fracture of GFRP and meandered the fracture path, then resulted in superior quasi‐static fracture performance than the basic Glare.

Theoretical Modeling and Experimental Verification of the Bending Deformation of Fiber Metal Laminates.

Fiber metal laminates have been widely used as the primary materials in aircraft panels, and have excellent specific strength. Bending deformation is the most common loading mode of such components. An accurate theoretical predictive model for the bending process for the carbon reinforced aluminum laminates is of great significance for predicting the actual stress response. In this paper, based on the metal-plastic bending theory and the modified classical fiber laminate theory, a modified bending theory model of carbon-fiber-reinforced aluminum laminates was established. The plastic deformation of the thin metal layer in laminates and the interaction between fiber and metal interfaces were considered in this model. The bending strength was predicted analytically. The FMLs were made from 5052 aluminum sheets, with carbon fibers as the reinforcement, and were bonded and cured by locally manufacturers. The accuracy of the theory was verified by three-point bending experiments, and the prediction error was 8.4%. The results show that the fiber metal laminates consisting of three layers of aluminum and two layers of fiber had the best bending properties. The theoretical model could accurately predict the bending deformation behaviors of fiber metal laminates, and has significant value for the theoretical analysis and performance testing of laminates.

A simulative study on the effect of friction coefficient and angle on failure behaviors of GLARE subjected to low-velocity impact

Abstract The aim of this paper is to study the effect of friction coefficient and impact angle on the failure behaviors of glass fiber reinforced aluminum laminates (GLARE) under the low-velocity impact (LVI) loading. A methodology is developed in commercial software ABAQUS/Explicit, and its accuracy is verified based on the results of comparison between simulation and experiment. In the simulation, Johnson–Cook flow stress model and surface-based cohesive behavior are carried out to simulate the damage evolution of aluminum alloy layers and delamination at the interface. Further, both the dynamic response history and damage mechanism characterization of these hybrid laminates are presented and compared carefully. Additionally, due to the advantage of simulation, it is accurate and easy to discuss on the evolution of the damage contour consisting of the damage degree of composite and metal layers as well as the interface between them. Finally, the influence rules of friction coefficient and angle on the failure behaviors of GLARE under LVI are drawn clearly.

Preface

This issue of the Journal of Physics: Conference Series contains the proceedings of the 2022 2nd International Conference on Mechatronics Technology and Aerospace Engineering (ICMTAE 2022). The conference took place in Nanchang, China during November 4th-6th, 2022 (virtual conference), with the attendance of about 100 prominent delegates in related areas all around the world.The conference aims at creating an international academic forum where current research results and technical advances can be exchanged and the development of mechatronics technology and aerospace engineering can be promoted. For this reason, scholars, specialists and researchers in related fields have come together at the conference to present their research activities, share their professional experiences, exchange new ideas, and discuss the key challenges and research directions facing the development of these fields.To make this conference on schedule, we have a three-part plenary conference including a keynote speech part delivered by four speakers from different countries. Among them, Assoc. Prof. Jiuming Xie from Tianjin Sino-German Universities of Applied Sciences-Mechanical Engineering College, China performed a keynote speech on the Preparation and Mechanical Properties of Aluminum Alloy 5A02/CFRTP Laminates. She took the Aluminum Alloy 5A02 /CFRTP (Carbon Fiber Reinforced Thermo-Plastic) laminates as the subject to conduct her research. Aluminum alloy was anodized, compression molding and 3D printing were adopted to prepare Carbon Reinforced Aluminum Laminates (CARALL) with two different structures: the solid core structure and the honeycomb structure, and the prepared specimens were then tested for mechanical properties via tensile test and three-point bending test, and compared with the performance of the conventional aluminum alloy. We are very optimistic that all participants will acquire new ideas and knowledge from this conference to enhance the capability toward mechatronics technology and aerospace engineering.We have received tremendous paper submissions from all over China and abroad. Through a rigorous peer-review process, all submissions were performed double blind review to check their quality of content, level of innovation, significance, originality and legibility. Based on the expertise review comments, some excellent papers were accepted and the corresponding authors were invited to submit their papers for final publication. The accepted papers included topics on: Materials Surface Physics, Combustion and Energy Conversion, Advanced Fluid Mechanics, Satellite and Geophysics, Aerospace Structures, etc.We would like to thank the Conference General Chairs and the Technical Program Committees for their hard work that lead to the organization of this event, to our colleagues who contributed to its realization, to the members of the Journal of Physics: Conference Series for their patience while waiting for the final versions of the papers and to every author who has contributed with an article to these proceedings. We firmly believe that all the attendees have had fruitful discussions and gained valuable knowledge, and will enjoy the opportunity for future collaborations.The Committee of ICMTAE 2022List of Committee member is available in this Pdf.

Theoretical analysis on carbon fiber reinforced aluminum laminate under off-center impact

Carbon fiber reinforced aluminum laminate (CARALL) composed of multi-layer CFRP and aluminum has better toughness and impact resistance than composite laminates due to the existence of metal. This work investigates the energy absorption mechanism and creatively proposes a theoretical analysis model to predict the dynamic response of CARALL under off-center impact. Firstly, based on a simplified ideal rigid-plastic material model, a unified yield criterion and its simplified method for hybrid plastic hinges are proposed. Then, the analytical solution for maximum transverse displacement and impact force of CARALL under off-center impact is established. Finally, it is verified by the simulation and discussed in detail. The results show that the established theoretical method can predict the structural response under low-velocity impact.

Preparation and mechanical properties of aluminum alloy 5a02/cfrtp laminates

Aerospace and military defense fields are posing higher requirement on the lightweight feature of structures. Subject of this study is the Aluminum Alloy 5A02 /CFRTP (Carbon Fiber Reinforced Thermo-Plastic) laminates. In the paper, aluminum alloy was anodized, compression molding and 3D printing were adopted to prepare Carbon Reinforced Aluminum Laminates (CARALL) with two different structures: the solid core structure and the honeycomb structure, and the prepared specimens were then tested for mechanical properties via tensile test and three-point bending test, and compared with the performance of the conventional aluminum alloy. The results show that under the condition of a same thickness, the tensile strength of CARALL specimens with the molded solid core structure and the 3D printed honeycomb structure reaches 256Mpa and 186MPa, respectively, which is 85.5% and 34.8% higher than that of the tensile strength of Al 5A02; under different bending modes, the maximum bending strength is 682Mpa and 525Mpa, respectively, which is 62.4% and 25.5% higher than that of Al 5A02. When the specimens are subject to tensile force, the separation of the metal layer and the fiber layer is the primary failure form, the fiber layer fractures, and the metal layer exhibits the necking phenomenon as the metal fibers are being pulled out. During the bending process, for different bending forms, there’re great differences in the bending strength of CARALL specimens prepared by the same method, the failure modes of the specimens vary greatly as well, and this is determined by the tensile strength of the carbon fiber layer and the tensile strength of AL 5A02. Enhancing the bonding strength between the metal layer and the fiber layer can improve the mechanical properties of CARALL. These research findings can provide a reference for the lightweight design of metals and Fiber Metal Laminates (FMLs).

Molding preparation and tensile properties test of carbon fiber reinforced aluminum laminates

Molding preparation and tensile properties test of carbon fiber reinforced aluminum laminates

Quasi‐static fracture characterization of fiber metal laminate with crack resistance curve based on δ5

AbstractFiber metal laminate (FML) is a hybrid composite typical in aircraft industry. It is necessary to effectively characterize the quasi‐static fracture performance of FML, considering the importance of damage tolerance design of aircraft structures and the complicated fracture mechanism of FML. In present investigation, glass fiber reinforced aluminum laminates (Glare) with middle cracks were tested under quasi‐static tensile load. The experimental crack resistance curve (R curve) based on the special crack opening displacement at original crack tip (δ5) was used for revealing the superior crack resistance of Glare laminate to aluminum sheet, which expressed in crack extension aspect was the extended critical crack length. This was thought to be benefit from the contributions of glass fiber layers and fiber/metal delamination, by performing the progressive damage analysis. Since δ5 can embody the elastic–plastic response of the crack but without need to interactively correct for crack tip plasticity. The δ5‐R curve‐based macro and meso fracture models were proposed to accurately predict the residual strength and stable crack extension of Glare laminate, which gave further evidence for the effectiveness of δ5‐R curve in characterizing the quasi‐static fracture performance of FML.

Energy dissipation mechanism of fiber metal laminate under low-velocity impact

Identification of the energy dissipation behavior of fiber metal laminate under low-velocity impact is necessary for understanding its impact response and damage mechanism, as the impact scenario is typical for energy conversion. In this paper, the glass fiber reinforced aluminum laminate (Glare) was tested under different impact energy to achieve typical low-velocity impact responses and damage patterns. By which the finite element model was built and verified to be effective, by employing the Johnson–Cook model for aluminum, Hashin’s criteria and exponential damage evolution law based VUMAT subroutine for GFRP, and bi-linear traction–separation cohesive zone model for their interface. Based on the history energy outputs on internal energy, elastic strain energy, plastic deformation dissipated energy, and damage dissipated energy in the finite element model. The contributions of the constituents in the energy absorption aspect of Glare were firstly revealed. Furthermore, how the energy was dissipated by the laminate and by the constituents, i.e., the distributions of energy evolutions in laminate and constituent levels, were clarified. Finally, damage evolutions of individual layers and the failure sequence of the entire laminate were elaborated. The results achieved have specified the energy dissipation mechanism and its association with the impact response of Glare.

Study on off-center impact behavior and damage characterization of carbon fiber reinforced aluminum laminate

This paper aims to explore the off-center low-velocity impact response and damage characteristics of carbon fiber reinforced aluminum laminate (CARALL). Progressive damage finite element models of CARALL considering the stiffness degradation and damage evolution of carbon fiber reinforced plastic (CFRP) were established using a user subroutine and verified by off-center impact tests with different impact energies. The motion propagation, damage, and spatial distribution of dynamic responses of CARALL impacted in different locations are studied. The results indicate that increase in impact distance from center dissipates more energy due to the more severe damage and failure of CFRP, while the off-center impact have a negative effect on the plastic energy absorption of metal compared with center impact. A quantitative expression is proposed to describe the spatial distribution of the maximum transverse displacement.

The effect of electrophoretic deposition of carbon nanotubes onto carbon fiber on the interlaminar resistance of carbon reinforced aluminum laminates

Functionalized multi-walled carbon nanotubes were deposited on the carbon fabric using ultrasonic-assisted electrophoretic deposition. The effect of carbon nanotubes (CNTs) deposition time and morphology on the mode I interlaminar fracture resistance of carbon reinforced aluminum laminates (CARALL) was investigated. The formation of a proper network of CNTs on the carbon fabric favorably deviated the crack growth into the carbon fabric layer and intensified the fiber bridging during the delamination. The CNT coating on the carbon fiber in conjunction with the alkaline-acid treatment on the Al substrate significantly promoted the interlaminar fracture initiation and propagation energies and stabilized the fracture behavior.

The effect of laser-texturing configurations on the interfacial resistance of carbon reinforced aluminium laminate

ABSTRACT Laser ablation can be incorporated for surface treatment of carbon-reinforced aluminium laminate (CARALL) with environmental benefit as compared to chemical treatments. In the present research, laser surface structuring with different patterns was implemented on the aluminium substrates. The effect of laser-texturing pattern on the performance of CFRP/Al (carbon fiber reinforced polymer/aluminium) interface was investigated by undertaking lap shear, modes I and II interlaminar fracture tests. The laser surface structuring developed micro topography on the metal adherent and enhanced the interfacial area, mechanical interlocks, fiber bridging and cohesive failure in the CFRP/Al interface. The X-pattern with six successive passes of laser ablation offered the highest laser surface coverage (85.6%), leading to the improvement of lap shear strength, mode I and II critical interlaminar fracture toughness as high as 40, 110 and 52%, respectively, as compared to the chemical treated samples.

Progressive Damage Behaviour Analysis and Comparison with 2D/3D Hashin Failure Models on Carbon Fibre-Reinforced Aluminium Laminates.

It is known that carbon fibre–reinforced aluminium laminate is the third generation of fibre metal materials. This study investigates the response of carbon fibre–reinforced aluminium laminates (CARALL) under tensile loading and three-point bending tests, which evaluate the damage initiation and propagation mechanism. The 2D Hashin and 3D Hashin VUMAT models are used to analyse and compare each composite layer for finite element modelling. A bilinear cohesive contact model is modelled for the interface failure, and the Johnson cook model describes the aluminium layer. The mechanical response and failure analysis of CARALL were evaluated using load versus deflection curves, and the scanning electron microscope was adopted. The results revealed that the failure modes of CARALL were mainly observed in the aluminium layer fracture, fibre pull-out, fracture, and matrix tensile fracture under tensile and flexural loading conditions. The 2D Hashin and 3D Hashin models were similar in predicting tensile properties, flexural properties, mechanical response before peak load points, and final failure modes. It is highlighted that the 3D Hashin model can accurately reveal the failure mechanism and failure propagation mechanism of CARALL.

Strain rate effect analysis of hybrid composites under the high-velocity impact

In this paper, the damage behavior of fiber metal laminate (FML) is studied under high-velocity impact (HVI) at different strain rates (1 s−1, 100 s−1, and 1000 s−1) for flat, hemisphere, and sharp nosed projectiles. A finite element model has been used to examine the damage modes and failure processes of carbon fiber reinforced aluminium laminates (CRALLs) under HVI. This study is based on continuum damage mechanics. The damage criteria for aluminium (Al) and carbon fiber composite layers are identified by Johnson-Cook (J-C) and Hashin damage models, respectively. To analyse the inter-laminar de-lamination caused by the HVI, a cohesive surface regulated by bi-linear traction-separation is applied. The CRALL ballistic limit is analysed for different projectiles, which strike at initial velocity ranges from 60 m/s to 150 m/s to the CRALL. The obtained numerical results are in good agreement with the literature experimental results, which indicates the model is permissible for further analysis. The obtained results show that if strain rate varies from 1 s−1 to 1000 s−1 then CRALL ballistic limit velocity increases for all projectiles. The CRALL ballistic limit is the highest for flat nosed projectiles, followed by hemisphere and sharp nosed projectiles.

Damage to inverse hybrid laminate structures: an analysis of shear strength test

Abstract Hybrid laminates with continuous fiber reinforcement, such as glass reinforced aluminium laminate (GLARE), aramid reinforced aluminum laminate (ARALL), or carbon reinforced aluminum laminate (CARALL), have been developed to increase the lightweight potential and fatigue resistance applied for aircraft structures. However, the use of thermosetting matrices imposes material limitations regarding recycling, malleability, and manufacturing-cycle times. The inverse hybrid laminate approach is based on a continuous fiber-reinforced thermoplastic matrix, in which a metal insert is integrated. For efficient manufacturing of the novel composites in high-volume production processes, conventional sheet metal–forming methods have been applied. It helped to reduce the cycle times and the costs of the forming equipment compared to currently used hybrid laminate-processing technologies. The present study analyzes the damage to the inverse hybrid laminate structures resulting from the interlaminar shear strength test. The tests were performed for eight laminate material configurations, which differed by the type and directions of the reinforced glass and carbon fibers in the polyamide matrix and the number of the fiber-reinforced polymer (FRP) layers in the laminates. Industrial computed tomography and scanning electron microscopy were used for analysis. Observed damages, including fiber–matrix debonding, fiber breakages, matrix fractures, interfacial debonding, and delamination in selected areas of the material, are strictly dependent on the laminate configurations. FRP layers reinforced by fibers perpendicular to the bending axis presented better resistance against fractures of the matrix, but their adhesion to the aluminum inserts was lower than in layers reinforced by fibers parallel to the bending axis.