Fiber Metal Research Articles

Moisture‐Insensitive Force Sensor Yarns and Fabrics to Monitor Biological Motion

AbstractTextile sensors are crucial unobtrusive devices attached to arbitrarily curved surfaces owing to their high flexibility and ease of processing in large areas with complex contours. However, issues regarding the reliability and stability of the output of textile sensors and their practical implementation persist. This study proposes sensor yarns comprising carbon‐coated multifibers covering metallic core yarns to detect pressure and strain. Two electrically independent metallic core fibers are twisted in close proximity in a core‐sheath structure with a sheath yarn of carbon‐coated fibers. When an external force is applied, the covering yarns deform elastically, causing a change in resistance. The proposed sensor yarns can be used to develop customized textile sensors, as they can be woven or knitted at the target positions owing to their flexibility. Fabrics and knits with embedded sensor yarns can detect external forces and biological motions, e.g., respiratory monitoring and finger movements. The proposed sensors can be made sensitive or insensitive to moisture depending on the choice of the covering yarn. Thus, the proposed yarns and textile sensors have potential applications in wearable devices and biological sensors that require high conformability to the human body and curved surfaces.

Microcapsules in Fiber Metal Laminates for Self-Healing at the Interface between Magnesium and Carbon Fiber-Reinforced Epoxy.

The paper presents issues regarding self-healing isophorone diisocyanate (IPDI) microcapsules applied in fiber metal laminates (FMLs) based on magnesium AZ31 and a carbon-reinforced polymer composite. The aim of this work is to analyze the morphology of the produced PU/PUa microcapsules containing IPDI and their behavior in a self-healing layer in FMLs. By means of SEM, it was confirmed that the microcapsules (MCs) had a narrow size distribution. Therefore, the developed MCs, having sizes ranging from 10 to 35 µm, might contribute to an improved self-healing coating, which benefits from the advantages of both small and larger-sized MCs. The positive result of the work is that there is a possibility to improve the properties of FMLs with added MCs, i.e., in corrosion and mechanical phenomena.

Inter-ply friction behaviour in the temperature assisted forming of magnesium/glass fibre reinforced thermoplastic polymer laminates

The paper investigates the metal/prepreg inter-ply friction behaviour in thermoplastic fibre metal laminates (FMLs) based on magnesium alloy and glass fibre-reinforced polymer (GFRP) under a range of parameters (normal pressure, relative sliding velocity, temperature) that are typical of forming processes conducted at elevated temperature on FMLs. The surface roughness of metal sheets was also varied and its influence on the inter-ply friction behaviour was evaluated. Pull-through tests with a stop-start controlling strategy were designed and carried out for identifying the inter-ply friction coefficient at varying conditions. To support the quantitative data from the tests microscopic observations were performed on the residues of the prepregs left on the tested metal sheets. The obtained results proved that the differences in the friction coefficient are strongly dependent on the process conditions and the metal surface roughness. The increase in the relative sliding displacement enables the transition from the hydrodynamic to the mixed lubrication mode according to the Stribeck theory, which further rises the friction coefficient. The inter-ply friction coefficient is observed to increase at decreasing temperature and normal pressure, and at increasing sliding velocity and metal surface roughness.

Free Vibration-Based Delamination Detection in Fiber Metal Laminates Composite Beam

Delamination is a typical flaw in fiber-metal laminated composite structures that, when hidden from view, can significantly lower structural stiffness and alter a structure's ability to respond dynamically to forces like natural frequencies. Delamination is undoubtedly an important topic as it causes the performance of the Fiber Metal Laminate structures in the service to worsen. Delamination detection and severity analysis are essential in the aerospace industry for both safety and cost reasons. Although natural frequencies do not directly reveal the location or extent of damage, they are the most dependable metrics for damage detection. Frequency shifts in various modes are used to solve the inverse problem to pinpoint the damage location and extent. The bending natural frequencies shift brought on by delamination is utilized as an input to predict the delamination parameters. This study used an approach based on machine learning and a regression model to find the delamination parameters, i.e., locations and severity, in fiber metal laminated cantilever beams. FEA simulations using ANSYS were used to get the dataset pertaining to the position, severity, and eigen values (or bending natural frequencies) of the delamination. The results of this study indicate that the delamination locations and severity predictions developed using machine learning and regression models are reasonably accurate and demonstrate good agreement with the observed data.

Comparisons of the Performance of Novel Lightweight Three-Dimensional Hybrid Composites against GLARE Fiber–Metal Laminate

The objective of the work presented in this paper is to overcome several major shortcomings of the recently introduced 3D composites (3DCs) and their fiber–metal-laminate renditions (3DFMLs). A new class of lightweight, stiff, and resilient three-dimensional hybrid composites (3DHCs) is introduced in this study, referred to as “inserts enhanced 3D hybrid composites” (IE3DHCs). The performances of all configurations were characterised by conducting three-point flexural tests using a span-to-thickness ratio of 32:1. The flexural performance of 3DFMLs with different core thicknesses was first compared using GLARE-3/2-0.4 as a baseline, revealing the superior performance of 3DFMLs; the optimal performance was exhibited by 3DFML with a 3DC core. However, the lower ductility of 3DFMLs, as well as their poorly controlled and time-consuming fabrication process were recognized. The newly developed materials (IE3DHCs) had a comparatively simpler fabrication processes with significantly higher quality control. More importantly, IE3DHCs exhibited an approximately improvement in ductility and as much as a 250% improved design strength compared to 3DFMLs. These findings showcase the promising potential of IE3DHCs for future research and real-world applications. Additionally, robust finite element models were developed to simulate flexural tests and optimize future renditions of the IE3DHCs.

In-situ precipitation of ultrafine Mg2Ni particles in Mg-Ni-Ag metal fibers and their hydrogen storage properties

The intermetallic compound Mg2Ni shows improved hydrogen de-/absorption kinetics and a lower desorption temperature compared to pure Mg. However, the coarse Mg2Ni phase and its limited hydrogenation capacity restrict the application of the Mg2Ni alloy. In this study, an attempt was made to prepare Mg-Ni alloy fibers with a higher Mg content and a well-distributed Mg2Ni catalytic phase using the melt extraction (ME) method, and a unique metallic glass fiber was formed. With pre-annealing at 350 °C in a vacuum, uniformly dispersed Mg2Ni nanoparticles are in-situ formed, the phase transition is revealed to be metallic glass → Mg6Ni → Mg2Ni + Mg. About 1.5 wt% of hydrogen can be absorbed by the Mg-Ni fibers at 50 °C, and it is completely released in 8.8 min at 225 °C. Both the JMA and Kissinger models were utilized to accurately characterize the dehydrogenation activation energy, and the values of 90.4 and 95.8 kJ/mol were obtained, respectively. The hydrogen desorption process involves two distinct processes, the decomposition of Mg2NiH4 nanoparticles and MgH2 hydride in sequence, with dehydrogenation enthalpy changes of 64.5 and 78.2 kJ/mol, respectively. After hydrogen absorption and desorption cycles, a loose structure forms around the Mg2Ni nanoparticles. This structure serves as an efficient nucleation site for hydrides and provides diffusion paths for H atoms.

Transition in wear regime during braking applications: An analysis of the debris and surfaces of the brake pad and disc

This article aims to describe the sequence of events (cause-effect) that lead to the transition in wear regime from moderate to severe for brake friction materials (BFM). Tribofilm, contact plateaus and wear debris are characterized in both regimes through different techniques. It was concluded that there is a critical tensile strength which leads to the destruction of the contact plateaus (the secondary type), resulting in a direct contact between the metallic fibers of the BFM and the tribofilm deposited on the disc’s surface. Then, the tribofilm is gradually removed over the braking applications, increasing the wear rate of the tribopair.

Experimental analysis of the quasi-static penetration test on fiber metal laminated plate reinforced by nano-silica

FMLs are lightweight hybrid materials that possess specific static properties, impact resistance, fracture resistance, and fatigue resistance. These characteristics make FMLs highly desirable for various applications in the transportation industry (Hu et al., 2015 Dec 1) [2].The present study aims to scrutinize the energy absorption and strength characteristics of a kind of Fiber Metal Laminate (FML) reinforced with Nano silica (0, 0.3, 0.6, and 0.9 wt %) that is fabricated from braided fiberglass and carbon fiber sleeve and aluminum 2024-T3. Sleeve-type braided fiberglass, carbon fiber and highly adhesive resin were introduced as interlayers. The arrangement of FMLs layers was in 2 types, first AL/Glass/Glass/Glass/Glass/AL and second AL/Glass/Carbon/Carbon/Glass/AL. The produced FMLs were tested to evaluate the behavior and strength characteristics under quasi-static indention. Quasi-static indentation test performed with spherical head penetrators at a 5 mm/min rate. The experiment continued until the indenter fully penetrated the specimen. These FMLs crushed progressively and are unlikely to fail under catastrophic failure, although specimens with 0.6% Nano silica in glass fiber and specimens with 0.3% in the glass and carbon fiber have better performance. A comparison of the results of glass FMLs with hybrid FMLs shows that Nano silica-reinforced glass fibers have achieved better results than hybrid fiber. To study the structure of amplified FMLs, electron microscopy (SEM) imaging was used which showed that in FMLs with better results, Nano silica was evenly distributed on the layer of epoxy resin. The results also indicate that the mechanical performance of a new FML has a good potential to be applied as a new and efficient energy absorber.

Numerical analysis of particulate Reiner–Rivlin flow in an asymmetric convergent channel with a heat source and magnetic field

ABSTRACT The goal of the current investigation is to examine the impact of magnetic field and heat source effects on a Reiner–Rivlin particulate flow through an asymmetric channel (convergent channel). The transformed governing equations are solved by employing the shooting technique with the RK4 method. To check the convergence of the computational results, a grid independence test has been performed. The impact of influential parameters on fluid as well as particle phases of velocity and temperature fields have been analyzed graphically. The present results exactly match previously published results in some limited cases. As the Reynolds number and magnetic parameter increase, the fluid phase velocity increases on the left side and decreases on the right part of the channel. Different fields, including metal steam resistors, paper production, and fibre suspension, are significantly impacted by the magnetic field’s effect on Reiner–Rivlin fluid through asymmetric channels.

High-velocity penetration impact characteristics of fiber metal hybrid cylindrical shells: Theoretical and experimental investigation

The high-velocity penetration impact characteristics of fiber metal hybrid (FMH) cylindrical shells are investigated. A finite element (FE) model of such a shell subjected to an internal high-velocity projectile impact is established based on ABAQUS software to predict impact parameters, in which the impact damage failures of FRP, metal, and virtual cohesive layers are considered, respectively. Both literature and experimental results are utilized to verify the current model, with the influences of critical parameters on the residual velocity and specific energy absorption properties being discussed. The outputs provide valuable references for evaluating the high-velocity impact resistance of such structures.

The Effect of Core Metal Layer Thickness on the Behavior of Carall Under Low Velocity Impact Loading

Fiber metal laminates are the advanced composite materials, in which the metal and FRP layers are stacked alternatively to achieve the desired properties. The presence of FRP layers enhances the fatigue, fracture properties and weight savings. Durability and plasticity of the metal plays a significant role in the design of fiber metal laminates. This study evaluates the role of middle metal layer (core) thickness on the behavior of Carall fiber metal laminates under low velocity impact loading. Two types of Carall 3/2 with middle layer of varying thickness are considered. The metal volume fraction is same for both the laminates. Finite element simulations have been carried out for the laminates considered according to the standard ASTM D7136. Johnson–cook plasticity and damage model and two-dimensional Hashin damage criteria have been used to model the aluminum and CFRP respectively. From the study, it was found that the placement of thicker layer at the middle position in the Fiber metal laminate enhances the impact resistance of Carall. The energy absorption studies also indicate that the presence of thicker layer at the middle position increases the energy absorption capability.

Role of fiber dosages and lengths on the mechanical strength, shrinkage, and pore structure of CO2-cured amorphous metallic-fiber-reinforced belite-rich cement composites

The impact of varying dosages and lengths of amorphous metallic fiber (AMF) on the mechanical strength, shrinkage, and pore structure of fiber-reinforced cementitious composites cured in water and in a carbonation chamber were assessed. This study evaluated fourteen mortar mixes, i.e., seven mixes for traditional water curing and seven for CO2-curing (60% relative humidity, 20 °C, and 10% CO2 concentration). The outcomes reveal that the compressive and flexural strength are significantly augmented for the mixes reinforced with AMFs as compared to the control mix (fiber-free mix), and this behavior is more pronounced with increased dosages and lengths of the AMF. Furthermore, compared to the control mix, significant mitigation in the development and magnitude of shrinkage was recorded with increased dosages and lengths of the AMF. The porosity and voids were all increased in the samples with AMF as compared to the control mix. The carbonation-cured specimens exhibited significantly higher mechanical strength, fewer voids, and higher shrinkage than those cured in water. Based on the experimental findings, it is recommended to use 0.50% volume of AMF and a length of 20 mm to produce fiber-reinforced cement composites, as this combination provides outstanding performance among all mixes tested here.

Probabilistic Relative Entropy in Homogenization of Fibrous Metal Matrix Composites (MMCs).

The main aim of this work is to deliver uncertainty propagation analysis for the homogenization process of fibrous metal matrix composites (MMCs). The homogenization method applied here is based on the comparison of the deformation energy of the Representative Volume Element (RVE) for the original and for the homogenized material. This part is completed with the use of the Finite Element Method (FEM) plane strain analysis delivered in the ABAQUS system. The probabilistic goal is achieved by using the response function method, where computer recovery with a few FEM tests enables approximations of polynomial bases for the RVE displacements, and further-algebraic determination of all necessary uncertainty measures. Expected values, standard deviations, and relative entropies are derived in the symbolic algebra system MAPLE; a few different entropy models have been also contrasted including the most popular Kullback-Leibler measure. These characteristics are used to discuss the influence of the uncertainty propagation in the MMCs' effective material tensor components, but may serve in the reliability assessment by quantification of the distance between extreme responses and the corresponding admissible values.

Mechanical and vibration behavior of surface‐modified titanium sheet interleaved with woven basalt/flax fiber metal laminates

AbstractIn fiber metal laminates (FMLs), the order in which fibers with different natural properties are stacked is very important for making materials that absorb vibrations and have good mechanical properties for structural applications. Hence, the present study focuses on the mechanical and vibration characteristics of FML designed with multi‐order energy‐absorbing flax fiber and high‐strength basalt fiber stacking covered with titanium sheets. The fabricated FMLs were designed with titanium/basalt fiber laminate (Ti/B), titanium/flax fiber laminate (Ti/F) and titanium/multi‐order‐flax‐basalt fiber laminate. The mechanical characteristics including tensile, flexural, and impact strength; and vibration characteristics of prepared FMLs were investigated. The higher tensile and flexural strength were revealed in an FML consisting of basalt layers (Ti/B) laminate than the flax core part (Ti/F) due to the strongness of basalt fiber, increasing the capability of load‐bearing of composites. Ti/B FML showed a maximum tensile strength and flexural strength of 412 and 450 MPa. Furthermore, flax fiber absorbs more energy, so the flax layer's inbuilt structure increases energy absorption during impact and vibration testing. Ti/F exhibits the highest impact strength (427.8 kJ/m2) and Ti/B exhibits the lowest impact strength (312.5 kJ/m2) because flax fibers are more ductile than basalt fibers, increasing the toughness of the FML. Ti/F FML structure, the greatest natural frequency of modes 1, 2, and 3 (549.03, 715.07, and 956.15 Hz) was observed. Natural fiber hybridization designed for FML, such as the Ti/B/F laminate, improved mechanical and vibration properties, making it suitable for structural applications.Highlights Fiber metal laminates were designed with titanium/flax/basalt. FMLs stacked composites significantly affect the mechanical properties. The basalt fiber, increases the capability of load‐bearing of FMLs. The damping of FMLs increases with the increase in flax fiber layers. Flax‐basalt fibers stacked FMLs produce tunable impact and vibration energy.

Elucidation of Static Fracture Energy and Dynamic Tensile Performance of Hybrid Steel Fiber-Based Ultrahigh-Performance Concrete

Ultrahigh-performance concrete (UHPC) has great potential for applications in civil and military structures due to its outstanding performance and ability to withstand impact and blast load. This performance can be attributed mainly to the materials and their proportions, especially metallic fibers. Hence, understanding the behavior of UHPC under static and dynamic conditions through the effect of hybridization of steel fibers is essential. Compressive strength and flexural strength were studied in quasi-static mode. In flexural mode, strain characterization was done using a digital image correlation (DIC) technique. Fracture studies were also conducted with notches using a crack mouth opening displacement (CMOD) technique. In high-strain mode, dynamic tensile strength was evaluated using a split Hopkinson pressure bar (SHPB) with a Brazilian disk. Owing to optimized hybridization, enhancement in (1) toughness, (2) energy absorption, (3) crack-resistance capacity, (4) reserve strength, (5) limit of proportionality, (6) fracture energy, (7) stress intensity factor, (8) tensile strain carrying capacity, and (9) dynamic tensile strength were observed. In the process, other findings in relation to fracture, strain rate, and dynamic increase factor were also exemplified. The SHPB dynamic tensile test results, as well as the technical information provided regarding UHPC’s hybrid steel fibers’ strength, failure, and fracture behavior, can be used to improve the design of UHPC building structures to protect against impact and blast attacks.

On the impact of pad material ingredients on particulate wear emissions from disc brakes

Besides friction and wear, airborne particle emission has become a central parameter when evaluating disc brake performance due to its potential adverse health effects as component of ambient air pollution. The pad friction material of brake system is composed of a mixture of ingredients grouped into four material categories: abrasives, reinforcing fibres, lubricants, and fillers. Some other ingredients which do not typically belong to aforementioned categories can be attributed to “fixed material”, such as aramid fibre, which is usually added into brake pad to harmonize the overall tribological properties. There is a gap of knowledge about how one ingredient from one category contributes to the emissions of particle number (PN) and mass (PM2.5, PM10). To investigate this, one ingredient from each category was chosen and produced as pins. As a reference, pins made of a commercial European brake friction material were also produced. The pins were tested using a pin-on-disc tribometer designed for airborne emission studies. Coefficient of friction, particle mass and number concentrations were measured during the tests. The results indicate that the abrasive and metal fibre have PN, PM2.5, and PM10 emission factors that are orders of magnitude higher than the lubricant and aramid fibre.

Dynamic experimental study of nitinol wire-reinforced composite structures

Due to the advantages of both the metallic and glass fiber qualities, glass fiber reinforced metal layers are one of the best impact resistant materials. Shape memory alloys have also been thought to be effective materials for equipping the traditional impact-exposed materials due to their high impact damping capabilities. The modal response (natural frequencies, damping, and vibration amplitude) of the laminate composite constructions that incorporate shape memory wires was experimentally investigated in this article. The goal of the current research is to ascertain how the modal responses are impacted by three production parameters: wire diameter, wire location, and wire number. Using an experimental design plan and a central composite design, hybrid specimens were planned. The results showed that the manufacturing variables influence all the modal responses in different proportions. Regarding the innovations in the construction of this type of hybrid composite, this study could be used in the design of mechanical and airspace structures.

Out-of-plane static loading performance of lightweight aluminum/composite FML structures for retrofitting applications: Effectiveness of bonded, bolted and hybrid bonded/bolted joining techniques under hydrothermal aging environment

This study evaluates the mechanical response for different flexural loading direction scenarios of the fiber metal laminates (FMLs), an aluminum structure retrofitted with basalt fiber-reinforced epoxy-based composites for aircraft applications. The static bending load-carrying effectiveness under hydrothermal aging of FMLs joining with bolted, bonded, and hybrid bolted/bonded (HBB) techniques were investigated, and damage formations were discussed through post-fracture morphological analyses. Besides, the adhesive was modified by adding halloysite nanotubes (HNTs) to increase the bond durability, especially against the aging environment. Test results showed that HBB structures generally provided superior aging durability compared to other connection types. It was also concluded that the basalt/aluminum FMLs exhibit a more effective load-carrying performance when the aluminum component is positioned under the neutral axis, preventing abrupt load drops. For untreated, wet, and dried conditions, the load-carrying capacities of HBB (nano-adhesive and four bolts) specimens exhibited enhanced load-bearing performance by 24–34%, 25–42%, and 29–30% compared to neat-adhesively bonded samples. Moreover, HBB structures improved performance for the same conditions by 114–141%, 127–155%, and 102–146%, respectively, compared to only-bolted (two bolts) specimens. This study provides insights into the potential use of basalt fiber-reinforced polymer composites BFRPCs in retrofitting aluminum for aerospace applications.

Vibration Behaviors of Antisymmetric Fiber Metal Laminated Composite Plates

Vibration Behaviors of Antisymmetric Fiber Metal Laminated Composite Plates

Dynamic impact behavior and notched fatigue life of GLARE laminates

As a member of the fiber metal laminates (FMLs) family, GLARE laminates have been widely used in aircraft skin structure due to the excellent resistance to dynamic impact and fatigue loadings. The low-velocity impact of GLARE laminates are conducted to explore the mechanical response on the impact energy and punch shape. The impact indentations are characterized by the damage morphology and quantitative dimension analysis. The mechanism of impact damage resistance is illuminated by the contact force-time curve, intra-laminar and inter-laminar damage modes. The lagrangian SPH modelling is employed to numerically analyze the bird-strike behavior of GLARE laminates, revealing the variation of bird particle flow and impact energy with different impact attitudes. The tension-tension fatigue of GLARE laminates is experimentally performed subjected to different stress levels. The influence of the circular open-hole on the fatigue residual life of GLARE laminates is studied. Considering the uncertainty of S-N curves, the probabilistic fatigue life P-S-N curves are developed under different survival probabilities. These would be more positive for the fatigue life estimation and reliability design for GLARE laminates in aircraft engineering application.