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In the present study, the sound transmission loss (STL) through the air-filled rectangular double-walled cross-ply fiber metal laminated (FML) nanoplates under simply supported and clamped boundary conditions is studied using the nonlocal strain gradient theory (NSGT) and third-order shear deformation theory (TSDT). NSGT is complemented with hardening and softening material effects, which can significantly enhance the accuracy of small-scale results. The sound velocity potential and Hamilton's principle are employed to derive the coupled size-dependent vibroacoustic equations. The Galerkin method is exploited to solve vibroacoustic equations and obtain the STL. The developed solution is examined in terms of its accuracy and precision via a comparison with other available data in existing research. The effects of different parameters such as boundary conditions, nonlocal and strain gradient parameters, lay-ups, incident angles, and acoustic cavity depth on the STL through the double-walled FML nanoplates are investigated. [ABSTRACT FROM AUTHOR]

In selective laser etching for the interfacial strengthening of Fiber Metal Laminates (FMLs), the wettability of customized structured features significantly affects their overall mechanical properties. For two-level features, their complicated geometry makes the evaluation of wettability difficult, which introduces challenges to feature design. In this study, a sandwich FMLs comprising an AA2024-O metal skin and a plain-woven carbon-fiber fabric core is investigated. Three types of two-level feature interfaces are designed and introduced into the FMLs structure. To understand the effect of two-level features on the resin flow and dynamic wetting progress in resin transfer molding, two-phase flow Computational Fluid Dynamics numerical models coupled with porous media and level-set numerical methods are built. The feasibility of the numerical simulation in the qualitative analysis was verified by comparing the results with those of the testing porosity values from X-ray scanning. In addition, the mechanisms of pore formation and transportation are revealed. These results indicate that the deeper groove structure in the etched features plays an important role in discharging residual air and determining the transformation of pores to reduce porosity. The permeability orientations of the porous media and surface structure both have significant impacts on the flow behavior and formation of pores. [ABSTRACT FROM AUTHOR]

This study looks at the mechanical and free vibration properties of glass laminated with functionalized aluminium reinforced epoxy. NaOH, K2Cr2O7, Fe2(SO4)3. XH2O, and C8H18O3Si were employed to functionalize aluminum. The flexural, impact, and shear strengths, as well as their failures, were investigated using electron microscope images. The impulsive hammer approach was applied to investigate laminate vibration behaviour. The results showed that the flexural strength (623.83 MPa), impact strength (76.41 J/mm2), and shear strength (55.31 MPa) of C8H18O3Si functionalized laminates outperformed those of other functionalized laminates. The improvement of mechanical properties was due to the change in interfacial adhesion. This is dependent on the functionalization of aluminium used in stacked laminates. Moreover, C8H18O3Si functionalized laminates exhibit a higher natural frequency and higher damping than other functionalized laminates. This natural frequency and damping are enhanced due to the strong mechanical interlocking between polymer and metal adhesion. It was noted that the same laminates have higher toughness than other laminates because of the high impact energy obtained. [ABSTRACT FROM AUTHOR]

To investigate the enhancement mechanism and effect of laser treatment on the performance of an interface between a carbon-fiber-reinforced polymer and magnesium (CFRP/Mg), finite element simulations and experiments were conducted to demonstrate the macroscopic and microscopic failure processes of the laser-treated interface. Based on the high controllability of the groove parameters in laser machining, the quantitative relationship between the texture parameters and the shear properties of the CFRP/Mg interface was analyzed. In addition, shear tests and simulations of the laser-treated interfaces with different groove parameters were performed. Increasing the groove depth and decreasing the groove spacing effectively improved the shear strength of the CFRP/Mg interface. In addition, the reliability of the interface cohesion parameters obtained using the representative volume element model was verified by experiments and simulations, which is important for the application of laser technology to composite laminates. [ABSTRACT FROM AUTHOR]

In addressing the difficulty of forming Fiber Metal Laminates (FMLs), a laminate composed of a 0.1 mm-thick 304 Stainless Steel Foil (SSF) and Carbon Fiber Reinforced Plastics (CFRP) as the base material is prepared using a specific process. Subsequently, forming limit diagrams are obtained through hemispherical bulge forming experiments to investigate the forming performance of FMLs laminates. The damage phenomena of various forming specimens during the thermal stamping process are analyzed. Based on different damage forms, corresponding theoretical models are established to simulate and predict the forming damage modes of FMLs through simulation. The research results indicate that the stamping formability of FMLs is influenced by the damage tolerance of the thin stainless steel foil. During the thermal stamping process, FMLs may experience delamination, fracture/crack of the thin stainless steel foil, and rupture/tearing/wrinkling of the prepreg. To address these issues, cohesive elements, GTN-M-K damage, and Hashin damage models are established, providing a reasonable simulation prediction of the stamping damage phenomena of FMLs. [ABSTRACT FROM AUTHOR]

Abstract Fiber metal laminates (FMLs) are widely applied as protective structures in various high-tech industries owing to their excellent impact resistance. This paper presents an explicit finite element (FE) simulation to investigate the dynamic damage behavior of carbon fiber-reinforced aluminum laminates (CRALLs) under combined explosion and fragment loading. Johnson-Cook model is utilized to capture the damage response of aluminum material; 3D Hashin failure criteria are applied to predict the damage evolution of fiber composite material considering the high strain rate effect; cohesive elements are incorporated to simulate the inter-laminar delamination phenomena. The effectiveness of the proposed numerical model is verified through a comparison with available experimental data in ballistic impact conditions. In addition, a thorough analysis of the dynamic behavior and damage mechanism of FMLs is conducted, and the impact performance is extensively discussed in terms of the influences of explosion distance and explosion mass. This work serves as a valuable reference for future numerical studies on the explosive impact resistance of other FMLs structures. [ABSTRACT FROM AUTHOR]

The cutouts are commonly found in fiber metal laminates to facilitate to pass electrical wires, water/fuel lines and sometime to facilitate easy access and inspection. Sometimes, such cutouts need to be reinforced by providing stiffener around the cutouts to avoid pre-mature failures. This article addresses the effects of reinforced cutouts and non-linearly varying edge loads on the vibration and buckling performance of inter laminar hybrid fiber metal laminates (HFMLs) by utilizing finite element approach. Toward this a 9-noded heterosis plate element has been used to discretize both plate and stiffener by taking into account the effect of shear deformation and rotary inertia. The stiffener considered in this study is spread in nature. The displacement compatibility by the plate and stiffener is maintained by using transformation matrix. The effect of eccentricity of the spread stiffener is also incorporated within the transformation matrix. Since the stress distribution within the plate is highly non-uniform in nature, the dynamic approach has been used to solve the buckling problems. The present study consists of aluminum metal face sheets bonded with four layered symmetric hybrid cross-ply laminates, in which six different hybrid configurations have been considered. The performance of each hybrid configuration along with different sized and positioned reinforced cutouts is well investigated under various nonlinear loading conditions. [ABSTRACT FROM AUTHOR]

The low-velocity impact resistance of fiber metal laminates (FMLs) is investigated. FMLs with titanium alloy Ti-6Al-4V sheets and glass fiber/epoxy layers are fabricated using the hand layup technique, exhibiting the same total metal layer thickness. A drop tower is used to produce a low-velocity impact on the FMLs. FML with outermost metallic layers exhibits comparatively higher lateral spreading and interlayer delamination opening contrary to FML with more metallic layers. This is also observed in high-velocity impact. The low-velocity impact resistance of titanium-based FMLs seems higher than aluminum-based FMLs. This is also noticed in high-velocity impact for former and latter FMLs. [ABSTRACT FROM AUTHOR]

Mechanical properties and load vs. displacement diagrams, and fatigue life, mechanisms and load vs. cycles curves were received for fiber metal laminates (FMLs) with original and inclined edge cracks at room and elevated temperatures. The mixed mode stress intensity factors and J-integral of cracked FMLs were obtained. The bridging stresses was considered in the modified Paris Law to predict fatigue life of inclined crack FMLs. The predicted results of fatigue life with vertical cracks at room temperature were satisfactorily well. The fatigue life of samples with inclined cracks at elevated temperature the scatter was also acceptable within minor errors. [ABSTRACT FROM AUTHOR]

Owing to the increasing demand for high performance and lightweight materials, fiber metal laminates (FMLs) have become the alternative materials to replace metallic alloys. When the environmental friendliness of the materials is taken into consideration, plant fibers have shown an excellent potential to be employed as the reinforcements in FMLs. This work describes the mechanical behavior of kenaf and pineapple leaf fibers (PALF) reinforced metal laminates with various fiber contents, ranging from 10 wt% to 50 wt%. Fiber metal laminates were formed through the coalescence of metallic skin layers with the composite as the core. The mechanical tests were then conducted to study the tensile, flexural and Charpy impact properties of the structures. From the findings, it was concluded that both the kenaf and PALF based FMLs showed the optimum mechanical properties when the fiber content was fixed at 30 wt%. In addition, PALF based FMLs had shown higher mechanical properties over kenaf based FMLs. At a fiber content of 30 wt%, the tensile and flexural strength of PALF based FMLs were respectively 6.18% and 3.44% higher than kenaf based FMLs. In terms of impact properties, the impact strength of PALF based FMLs was 5.06% and 40.73% higher than kenaf based FMLs in the flatwise and edgewise orientations. [ABSTRACT FROM AUTHOR]

The effect of target condition (static and dynamic) and number of projectile impacts (single and multiple) on the ballistic performance of 6061-T6 Aluminum alloy, 7075-T6 Aluminum alloy and 6061- aluminum alloy Fiber Metal Laminates (FML) have been investigated. Both numerical and experimental approaches were used to predict the nature of target deformation and its kinetic energy absorption. Ballistic experiments were conducted using armor piercing projectiles (APP) of diameter 7.62 mm with velocities ranging between 330 to 450 m/s. Irrespective of the target material (6061-T6 aluminum alloy, 7075-T6 aluminum alloy), non-linear reduction of exit velocity of the projectile was observed for a single plate target. In contrast, large plastic deformation and 'petaling' mode of failure was observed for the FML and rubber sandwiched targets. Higher impact energy absorption of the FML target and rubber intruded 7075-T6 aluminum alloy plates is mainly due to the additional resistance offered by the individual layer of metal and fiber. In addition to projectile velocity, when the target (7075-T6 aluminum alloy plate) velocity was varied in the range of 10 to 40 m/s, significant reduction in exit velocity of the projectile was observed compared to static target. This is due the fact that, moving target has altered the penetration behavior of the projectile and additional increase of target velocity caused 'ricochet' of the projectile. In addition, when the target was subjected to multiple projectile impacts, gradual reduction of ballistic performance was observed. [ABSTRACT FROM AUTHOR]

The current work investigates the influences of different surface modifications on the flexural characteristics of carbon fiber reinforced aluminum (AA2024-T3) laminates fabricated at 3/2 sequence. Among all types of surface modifications, mechanical abrasion by 220-grit paper shows highest flexural strength. The flexural load of Al/0°/Al/0°/Al configuration is about 19% higher in comparison with mechanical abrasion (220-grit paper) with chemical treatment due to higher interfacial strength. However, corrosion resistance is improved about 30 times in the later modification. In-situ imaging reveals that failure of Al/0°/Al/0°/Al laminates initiates by micro-buckling of carbon fiber whereas matrix cracking initiates the failure in Al/90°/Al/90°/Al laminates. [ABSTRACT FROM AUTHOR]

This research focuses on the mechanical behavior of cost-effective novel hybrid fiber metal laminates (FMLs) based on aluminum (Al) 1050 alloy and jute/glass fiber reinforced epoxy composites. The effects of the stacking sequence and relative fiber amounts have been investigated. Specimens were fabricated using hand lay-up technique followed by compression molding. Results revealed that the reinforcement hybridization can potentially improve the tensile and flexural properties of FMLs based on jute fabric. The flexural strength of FMLs based on jute fabric has been improved when partial laminas from jute/epoxy laminate are replaced by glass/epoxy laminas. Also, it is realized that the incorporation of high strength fibers to the composite core leads to higher tensile properties but lower flexural resistance. [ABSTRACT FROM AUTHOR]

The increasing demand for high performance and lightweight materials has stimulated the development of alternative materials, namely fiber metal laminates (FMLs). FML is a sandwich structure which is formed by bonding the metallic layers with composite as core constituent using an adhesive agent. In this study, the mechanical behavior of FMLs with the core constituents of environmental friendly kenaf bast fiber reinforced polypropylene composites bonded with aluminum skin layers was investigated. The effects of fiber compositions (50, 60, and 70 wt.%), fiber lengths (30, 60, 90 mm), and alkali treatment on the mechanical responses of FML were investigated. The overall results revealed that the increase of fiber composition and fiber length reduces the mechanical strength of FML owing to the agglomeration of natural fibers when the fiber length exceeds the critical limit. However, the chemical treated kenaf bast fiber reinforced FML showed a significant enhancement of the mechanical properties in comparison to the non-treated fiber reinforced FML owing to the improved fiber-matrix adhesion level. [ABSTRACT FROM AUTHOR]

The fiber metal laminates (FML), consisting of carbon fiber reinforced polymer prepregs and magnesium alloys sheets, were introduced, and the Mode I (peel) and Mode II (shear) interlaminar fracture toughness of the FMLs were investigated. The results show that the Mode I interlaminar toughness (0.23 kJ/m2) of the FMLs is much lower than the Mode II interlaminar toughness (5.81 kJ/m2), due to the fact that the effects of mechanical interlock to hinder crack propagates is smaller under Mode I loading conditions than under Mode II. The FMLs mainly show adhesive failure and interfacial failure under Mode I loading conditions, while for Mode II loading, it exhibits a degree of epoxy cohesive failure except the adhesive failure and interfacial failure. [ABSTRACT FROM PUBLISHER]

Fiber metal laminates (FMLs) are the hybrid laminates consisting of alternating thin layers of metal sheets and fiber-reinforced composite material. Interface between metal and polymer layer plays a significant role. FMLs have both low density and high relative strength, and other good properties as high damage tolerance: fatigue and impact characteristics, corrosion, and fire resistance. In present work, the microstructure of the aluminum-epoxy/glass and aluminum-epoxy/carbon composites is characterized. The interface between metal and polymer composites with surface treatment and without surface treatment at different pressures was examined. It was observed that pretreatment of the aluminum has a significant effect on the zone between metal and polymer composite. In the interface, there is a direct contact between anodizing layer and resin without fibers, the same for epoxy/glass and epoxy/carbon laminates. The low pressure in autoclave process has a detrimental effect on the structure. It is responsible for the formation of the porosity and delamination in polymer layer and interface between aluminum and polymer composites. Untreated surface of aluminum sheet is characterized by too low adhesion to epoxy composite, especially with carbon reinforcement. [ABSTRACT FROM PUBLISHER]

Hybrid laminates made of polymer matrix composite plies with a metal sheet are called fiber metal laminates (FMLs). This study presents a new numerical approach for examining the fatigue damage progress in FMLs. A layer-wise finite element along with a cohesive element are used to predict the fatigue damage progress for splitting, transverse cracking and delamination. Four-node cohesive elements are introduced to express 0° ply splitting and transverse cracking. Eight-node cohesive elements are inserted into the ply interfaces to represent delamination. The most important character of this model is that the proposed simulation introduces a damage-mechanics concept into the degradation process in cohesive elements in order to express the damage progress due to cyclic loading. This enables us to address the complicated fatigue damage process observed in a FML. We applied this model to titanium/glass fiber-reinforced plastic (Ti/GFRP) laminates and compared the simulated results with the experiment data reported in the references. We confirmed that this model can reproduce the fatigue damage process in a FML. The effect of the parameters of the cohesive element on Ti crack growth and the delamination profile were also investigated. The Ti crack-growth rate was found to be strongly associated with the delamination profile near the crack tip. [ABSTRACT FROM AUTHOR]