This paper presents a comprehensive review of the state-of-the-art in structural battery composites research. Structural battery composites are a class of structural power composites aimed to provide mass-less energy storage for electrically powered structural systems. Structural battery composites are made from carbon fibres in a structural electrolyte matrix material. Neat carbon fibres are used as a structural negative electrode, exploiting their high mechanical properties, excellent lithium insertion capacity and high electrical conductivity. Lithium iron phosphate coated carbon fibres are used as the structural positive electrode. Here, the lithium iron phosphate is the electrochemically active substance and the fibres carry mechanical loads and conduct electrons. The surrounding structural electrolyte is lithium ion conductive and transfers mechanical loads between fibres. With these constituents, structural battery half-cells and full-cells are realised with a variety in device architecture. The paper also presents an overview of material modelling and characterisation performed to date. Particular reference is given to work performed in national and European research projects under the leadership of the authors, who are able to provide a unique insight into this emerging and exciting field of research.
ISSN: 2631-6331
Functional Composites and Structures is a new journal that will serve the international community by rapidly communicating high-quality research results and technological developments. This journal is co-owned by the Korean Society for Composite Materials (KSCM) and IOP Publishing.
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Leif E Asp et al 2019 Funct. Compos. Struct. 1 042001
Orhan Gülcan et al 2023 Funct. Compos. Struct. 5 022001
Many engineering structures, especially defense applications, need to be reinforced against blast loads due to a nearby explosion. Today, much more attention needs to be given to this issue because of increased exposure to explosions, and natural disasters. Different solutions have been used in the literature to mitigate blast-loading effects. One of these applications, sandwich panels, are a good candidate for blast-loading applications. In a sandwich panel structure, several parameters have considerable effects on deflections, deformations, and energy absorption capability. The most important of these parameters are: (i) the material and thickness of the front and back face sheets and core; (ii) core density and grading; (iii) core and face sheet types; (iv) filling and stiffening strategies of the core; (v) radius of curvature of the panel; (vi) mass of explosive charge; and (vii) standoff distance. The aim of this paper is to review these critical aspects of blast loading of sandwich panels to provide an overall insight into the state of the art of the application.
Anasheh Khecho and Erina Baynojir Joyee 2024 Funct. Compos. Struct. 6 015010
Additive manufacturing (AM) has drawn significant attention in the fabrication of soft actuators due to its unique capability of printing geometrically complex parts. This research presents the design and development of an AM process for bioinspired, deformable, and magnetic stimuli-responsive actuator arms. The actuator arms were fabricated via the material extrusion-based AM process with magnetic particle-polymer composite filaments. Inspired by the rhombus cellular structure found in nature, different design parameters, such as the line width of the interior rhombus sides, and 3D printing parameters were studied and optimized to fabricate actuator arms that exhibit enhanced flexibility while being magnetically actuated. The trigger distance and deformation experiments revealed that the width of the rhomboids' sides played a critical role in magnetic and bending properties. It was found that the sample with a line width of 550 µm and printing layer thickness of 0.05 mm had the maximum deflection with a measured bending angle of 34 degrees. The magnetic property measurement exhibited that the sample with a line width of 550 µm showed the maximum magnetic flux density of 3.2 mT. The trigger distance results also supported this result. A maximum trigger distance of 8.25 mm was measured for the arm with a line width of 550 µm. Additionally, tensile tests showed that the sample exhibited a 17.7 MPa tensile strength, 1.8 GPa elastic modulus, and 1.3% elongation. Based on these results, we successfully fabricated a 3D printed magnetic gripper with two rhombus cellular structured arms which showed grasping and extensive load lifting capability (up to ∼140 times its weight).
Ji-Hun Bae and Seung-Hwan Chang 2019 Funct. Compos. Struct. 1 012003
Electroactive polymers (EAPs) are materials that respond to electrical stimulation by exhibiting significantly large strains (to a maximum of a few hundred %) and vice versa. Thanks to their unique behaviors, EAPs have been widely and increasingly applied for sensing and actuating applications. EAPs are a promising material with many attractive properties such as fast electro-mechanical response, high mechanical and chemical stability, flexibility, low modulus, high strain capabilities, and shape adaptability. These features make them attractive for innovative applications such as wearable fabric sensors for IoT products and artificial muscles as bio-friendly actuators. In this article, we have presented a brief overview of electronic EAPs, especially PVDF-based materials, dielectric elastomers such as silicone and acrylic materials for sensors and actuators by focusing on their operation mechanisms and applications.
Dongju Lee et al 2023 Funct. Compos. Struct. 5 045007
With the growing importance of high-performance carbon fibers (CFs), researches have been conducted in many applications such as aerospace, automobile and battery. Since conventional CFs which were made from polyacrylonitrile, pitch and cellulose display either high tensile strength or high modulus properties due to structural limitations, it has been a challenge to develop CFs with both tensile strength and modulus with high conductivity. Therefore, various studies have been conducted to obtain high-performance multifunctional CFs. Among them, 1-dimensional carbon nanotubes (CNTs) have been used commonly to make CFs because of high mechanical and conducting properties. In this review, the recent development of CFs was introduced briefly, and CNT-based composite CFs were introduced. Many efforts are being made to create high-performance CFs by combining various carbon nanomaterials and polymers, which can have potential to be utilized in aerospace, defense and other industries. The those fibers may be nextgeneration high-performance fibers due to both high strength and high modulus as well as high conducting properties. The challenges and outlook for commercialization of CNT-based CFs are addressed in terms of aspect ratio of CNTs, solvent recycling, and mass-production.
Taniya Kulhan et al 2022 Funct. Compos. Struct. 4 022001
The use of polymer composite has been implemented since 3400 B.C, the very first known composite's application is attributed to the Mesopotamians. These ancient people fabricated plywood with glued wood strips placed at various distinct angles and in the late 1930s glass fiber thin strands have been developed. Glass fibre polymer composites have a wide scope in various engineering structures submarines, spacecraft, airplanes, automobiles, sports, and many more, over traditional materials because of their superior properties including lightweight, high fracture toughness, corrosion, fatigue, wear & fire resistance, high strength to weight ratio, high modulus and low coefficient of expansion. Various technologies have been developed so far to create different types of polymer composites in accordance with their properties and applications. Glass fiber possesses better properties as great strength, better flexibility, stiffness, and chemical corrosion resistance. Glass fibers are generally in the form of cut-up strand, fabrics and mats. Every kind of glass fibers has different properties and has various applications as in polymer composites. The aim of this review paper is to provide updated technological insights regarding the evolution of composite, classification of gass fibre polymer composites, development methodology in contrast with various applications, advantages and limitations and their behavioral properties.
Chidume Nwambu et al 2022 Funct. Compos. Struct. 4 045001
A dynamic mechanical thermal analyser operating in the single cantilever mode was used to examine the dynamic mechanical properties of unaged and hygrothermally aged discontinuous asymmetric helicoidal (Bouligand) carbon fibre reinforced plastic (CFRP) composites as a function of fibre architecture. The discontinuous Bouligand was manufactured using two major pitch angles as independent variables: 90° and 120° and from each major pitch angle, minor interply pitch angles were used as independent variables ranging 5°–25°. The composites were tested as either dry unaged specimens or following hygrothermal ageing in seawater at the constant temperatures of 40 °C and 60 °C for over 2000 h. We find that the viscoelastic properties E' and E'' are adversely affected by both hygrothermal aging and the minor pitch angle, but not the major pitch angle. Higher hygrothermal ageing temperatures and increasing minor pitch angles are found to decrease the energy absorption and dissipation capacities of discontinuous Bouligand structured CFRP composites. The tan-δ curves also indicate that hygrothermal ageing increases the heterogeneity of discontinuous Bouligand structured composites, with separate viscoelastic phases and glass transition temperatures.
Chae-Hwan Kim et al 2023 Funct. Compos. Struct. 5 015006
Auxetic structures with negative Poisson's ratio have received much attention due to their attractive behavioral properties in next-generation metamaterials and robotic applications. However, until now, there has been a lack of research into using soft materials to reliably develop a largely-deformable auxetic structures. Here, we develop soft polydimethylsiloxane (PDMS)-Ecoflex auxetic structures using a 3D printing technique, leading to high fabrication reliability and repeatability. Water-soluble filaments are employed to design sacrificial mold structures that quickly dissolve in warm water. By measuring the mechanical properties and light transmittance of soft composite membranes with various mixing ratios of PDMS and Ecoflex, the intrinsic characteristics of the composite membranes are determined. The newly fabricated soft auxetic structures composed of PDMS and Ecoflex composites always exhibit negative Poisson's ratio during stretching. The negative Poisson's ratio of the structure is maximized when PDMS and Ecoflex have a 2:1 mixing ratio and nominal strain is less than 5%. Advances in technology to reliably fabricate soft auxetic structures using 3D printers are believed to promote next-generation applications such as wearable sensors and energy-absorbing structures.
Dae-Hyun Han and Lae-Hyong Kang 2020 Funct. Compos. Struct. 2 025002
The objective of this paper is to study the performance of piezoelectric materials on a piezoelectric paint sensor. The paper begins by presenting a fabrication method for a paint sensor with piezoelectric properties using piezoelectric materials. The paint sensor is composed of piezoelectric powder and epoxy resin in a 1:1 weight ratio. Five different piezoelectric materials, including three soft-type and two hard-type materials, were used and their piezoelectric properties compared in paint sensors and ceramic sensors. The paint sensors were cured using a steel mold for producing a uniform specimen size of 20 × 10 × 0.2 mm3, and an electrode was made on the upper and lower sides using silver paste. Poling treatment was then successfully performed at room temperature (20 °C) under a 4 kV mm−1 electric field for 30 min in order to activate the paint specimen as a sensor. Impact signals were monitored by measuring output voltage from the paint sensor in relation to impact force. The sensor's piezoelectric properties were then calculated using normalized piezoelectric properties. In addition, five different piezoelectric ceramic sensors were fabricated and their d33 value measured to compare the sensitivity of paint sensors. As a result, Pb(Ni1/3Nb2/3)O3-Pb(Zr, Ti)O3 (PNN-PZT) powder showed higher sensitivity and higher piezoelectric properties than other piezoelectric materials in both paint and ceramic sensors.
Sayan Ganguly et al 2019 Funct. Compos. Struct. 1 022001
The serendipitous discovery of carbon dots has been added as a new domain of interest for materials scientists due to their extraordinary photo-physical attributes and long-term colloidal stability. This domain was more nurtured when carbon dots meet macromolecular chains. Carbon dot confined polymer matrices have diversified because of their ease of fabrication and applications in sensing, optoelectronics, semiconductors, molecular delivery, and various commercial aspects. Most promisingly, very small amounts of carbon dots have a over-the-top synergistic outcome in the presence of macromolecular systems. This review encompasses the synthesis of carbons dots, their physical properties, various fabrication strategies of polymer-carbon dots nanocomposites and applications.
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Ritesh Gupta et al 2024 Funct. Compos. Struct. 6 025007
Shape memory polymers (SMPs) are known for their unique ability to withstand large deformations and revert to their original shape under specific external stimuli. However, their broader application in biomedical and structural applications is restricted by limited mechanical and thermal properties. Introducing multi-walled carbon nanotubes (MWCNTs) into SMPs has proven to significantly enhance these characteristics without affecting their inherent shape memory features. This study investigates shape memory nanocomposites (SMNCs) through dynamic and thermogravimetric analyses, along with tensile, flexural, and shape memory testing, and explores fracture interfaces using scanning electron microscopy. Findings indicate optimal shape memory, thermal, and mechanical properties with 0.6 wt% MWCNT content, showcasing a shape recovery ratio of 93.11%, storage modulus of 4127.63 MPa, tensile strength of 55 MPa, and flexural strength of 107.94 MPa. Moreover, incorporating MWCNTs into epoxy demonstrated a reduction in recovery times by up to 50% at 0.6 wt% concentration. Despite a slight decrease in shape fixity ratio from 98.77% to 92.11%, shape recoverability remained nearly consistent across all samples. The study also introduces a novel finite element (FE) method in ABAQUS for modeling the thermomechanical behavior of SMNCs, incorporating viscoelasticity, validated by matching experimental results with FE simulations, highlighting its accuracy and practical applicability in engineering.
G Durango-Giraldo et al 2024 Funct. Compos. Struct. 6 025006
Natural rubber latex (NRL)—a polymer extracted from the rubber tree (Hevea brasiliensis)—has been used in multiple biomedical applications but does not have antibacterial properties. In this work, ZnO nanoparticles with two different morphologies were synthesized and added to NRL at different concentrations in order to evaluate the antibacterial properties of the resulting compounds. The characterization results obtained by electron microscopy and x-ray diffraction showed nanoparticles with spherical (mean size 69 ± 17 nm) and sheet morphology (mean size 154 ± 46 nm) with Wurtzite crystalline phase for both nanomaterials, respectively. The results of antibacterial tests showed that both compounds are effective against E. coli, and the reduction in bacterial viability was 90.3% and 96.4% for sheets and spherical nanomaterials, respectively. In the case of S. aureus, bacterial viability was reduced in both cases. The greatest antibacterial activity was evidenced in the nanoparticles with spherical morphology.
Minseok Kim et al 2024 Funct. Compos. Struct. 6 025005
Shape memory polymers (SMPs) can recall their original shape when exposed to environmental factors like heat, light, or magnetic fields. These SMPs are extensively used in medical applications, notably in stents, due to their shape memory and biocompatibility after implantation in the human body. However, conventional stents require balloons for expansion, limiting their flexibility. To address this, the study developed an SMP material that can regain its original shape without the need for a balloon. To effectively induce self-response, magnetically responsive Fe3O4 nanoparticles at concentrations of 10%, 15%, and 20% were integrated, and their dispersion was verified using scanning electron microscopy. The study also utilized differential scanning calorimetry to measure the glass transition temperature, crystallization temperature, and melting point of the synthesized polymers. The confirmation of uniformly dispersed nanoparticles revealed that the synthesized polymers exhibited a high shape memory ratio (84%–93%). Shape memory ratio represents the ability to return from a temporarily deformed state to the initial, original shape. Therefore, the biocompatible, magnetic-responsive SMP developed in this study has the potential to be utilized in various medical devices as an advanced shape-memory material.
Minseouk Choi et al 2024 Funct. Compos. Struct. 6 025004
Correlation between electrical, structural properties and electromagnetic shielding efficiency (EMI SE) of carbon nanotube sheets (CNTSs) was investigated. Solvent densification of CNTSs led to enhancements of carbon nanotube (CNT) bundling behavior and densification in the thickness direction while maintaining the areal density of the CNTSs. These structural modifications resulted in enhanced electrical properties and reduced sheet thickness by modifying the microstructure and bundling characteristics. Remarkably, contrary to conventional EMI shielding materials, the sheet resistance which reflects bundling behavior and microstructure of CNTSs, is the critical factor affecting the EMI SE of the CNTSs rather than electrical conductivity. The findings provide fundamental insights essential for the design of EMI shielding films incorporating CNTs.
Christina Wahyu Kartikowati et al 2024 Funct. Compos. Struct. 6 025003
Fe2O3/TiO2/AC nanocomposites were successfully synthesized via a sol–gel method, and their efficacy in decomposing methyl orange via adsorption-photocatalytic processes was reported for the first time in this study. Systematic exploration of the physicochemical properties impacting photocatalytic activity was conducted through x-ray diffraction, scanning electron microscopy—energy-dispersive x-ray spectroscopy, and Fourier transform infrared spectroscopy (FTIR) characterizations. The study revealed that the discoloration of methyl orange resulted from a synergistic interplay between adsorption and photocatalysis. The incorporation of Fe2O3 nanoparticles significantly elevated photocatalytic activity by 70%, with additional enhancement observed upon the introduction of activated carbon (AC) particles. The synergistic effects of AC adsorption and TiO2/Fe2O3 photocatalysis exhibited remarkable efficiency in degrading methyl orange under visible light irradiation. The trial functioning of Fe2O3 and AC in the TiO2/Fe2O3/AC composite, which serves as an adsorbent, an electron trap, and a co-catalyst providing active sites, significantly improved photocatalytic activity. These findings not only contribute to understanding the crucial role of composite TiO2 in conjunction with metal and carbon-based co-catalysts but also hold valuable implications for advancing research in the development of adsorption-photocatalytic systems for wastewater treatment.
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Mohammad Javad Ramezani and Omid Rahmani 2024 Funct. Compos. Struct. 6 012001
Auxetic materials, possessing a negative Poisson's ratio, can be arranged in various geometric configurations, such as tubular structures. Unlike conventional materials, which contract in lateral dimensions when stretched longitudinally, auxetic tubular expands in response to applied forces. This comprehensive review article amalgamates the latest experimental data and insights from preceding scholarly works, offering a detailed analysis of the structural design, fabrication processes, and mechanical characteristics of auxetic tubular structures. The review encompasses an analysis of their tensile properties, comparative evaluations with different materials, impact resistance, enhanced bending, and flexibility. Furthermore, the article explores the wide-ranging applications of auxetic tubular in diverse sectors such as automobile manufacturing, aerospace, medicine, and textiles. Furthermore, investigated not only new suggestions and future considerations for the advancement of these materials and structures but also a rigorous examination of the forthcoming and new challenges. This multifaceted approach distinguishes it from prior studies within the same scientific domain.
A Praveen Kumar and A Keshav Kumar 2023 Funct. Compos. Struct. 5 032001
Thin-walled energy absorbing structures based on hybrid structural concepts have a lightweight benefit along with great potential of enhancing the crashworthiness characteristics. Inspired by the huge number of research investigations performed on novel additively manufactured hybrid metal-composite configurations and their latest developments, the current review article extensively reports the latest advances along with promising outcomes of the impact response of various additively manufactured hybrid metal-composite structures for crashworthiness applications. Specific consideration is given to the crushing performance of the hybrid structures fabricated from fused deposition modelling technique. The significant additive manufacturing techniques, their material selections and exceptional customized structural designs explored in recent times are discussed elaborately. Crushing patterns obtained by hybrid energy absorbing structures under various loading conditions are recognized. Furthermore, comparison of various hybrid structures and their latest advances revealed the efficiency of the thin-walled hybrid configuration based on 3D printing techniques in terms of weight reduction, crashworthiness and energy absorption behaviour. This review article will serve as a catalyst to boost the scientific improvement of hybrid energy absorbing structures utilized as passive safety protective devices in modern vehicles.
Orhan Gülcan et al 2023 Funct. Compos. Struct. 5 022001
Many engineering structures, especially defense applications, need to be reinforced against blast loads due to a nearby explosion. Today, much more attention needs to be given to this issue because of increased exposure to explosions, and natural disasters. Different solutions have been used in the literature to mitigate blast-loading effects. One of these applications, sandwich panels, are a good candidate for blast-loading applications. In a sandwich panel structure, several parameters have considerable effects on deflections, deformations, and energy absorption capability. The most important of these parameters are: (i) the material and thickness of the front and back face sheets and core; (ii) core density and grading; (iii) core and face sheet types; (iv) filling and stiffening strategies of the core; (v) radius of curvature of the panel; (vi) mass of explosive charge; and (vii) standoff distance. The aim of this paper is to review these critical aspects of blast loading of sandwich panels to provide an overall insight into the state of the art of the application.
S Gowthaman 2023 Funct. Compos. Struct. 5 012005
Molecular dynamics (MD) simulation continues to be one of the most advanced tools in a wide range of fields and applications. The motion of atoms or molecules at various temperatures and pressures was analysed and visualised using the MD simulation through large-scale atomic/molecular massively parallel simulator (LAMMPS). This research focuses on a basic introduction to MD, as well as their determination and MD methods. LAMMPS works with a variety of external packages to determine the position of atoms and molecules over time. As the simulation has various procedures such as algorithm to step processing and results, the developers of MD are constantly pushing for the reduction of pre-steps. This classifies the performance competence that should be approached for increased portability of performance on a programmatic level, a key to implementing the solution for various problems that would come from inventors and possibly new research in programming languages.
Anna Cecília do Nascimento Pereira and Silvia Titotto 2023 Funct. Compos. Struct. 5 012004
Biomimetics enables the use of nature as a source of inspiration for the elaboration of high-performance materials. In this scenario, the development of bioinspired composites emerges as a promising proposal, capable of generating technological innovation in numerous areas of engineering, considering the exceptional mechanical performance of materials of this kind. That said, this review article characterizes the design principles and fundamental parameters for bioinspired composites design. In addition, the main challenges to be overcome in the development of bioinspired materials are discussed, with the presentation of some experimental studies that lead to the practical application of such principles. Future applications for this class of materials are also highlighted.
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Fal et al
Sandwich composite structures have an efficient structural design that provides high bending stiffness and strength at low weight. However, these structures are plagued with weak core-to-facesheet bond strength. In this work, the effect of increasing the contact area between the composite facesheet and honeycomb core was studied. Sandwich panels were manufactured using two different honeycomb structures, a regular and a modified honeycomb, and their respective bond strengths were evaluated using the flatwise tension test (ASTM C297). The honeycombs were additively manufactured using selective laser melting (SLM) process. The modified honeycomb was designed to have a larger surface area while retaining the same relative density as the regular honeycomb. The facesheets were made out of carbon-fiber, while the core was additively manufactured using 304L stainless steel powder. Impact specimens were manufactured and tested for impact resistance. A finite element model was created to study the integrity of the sandwich structures subjected to localized impact damage. The finite element model of the damage resistance due to impact showed a good agreement with the experimental results. Samples with increased contact area showed higher impact resistance. The average impact strength of the modified samples was 41.3% higher than the average impact strength of the regular samples. Flatwise tension results showed that by increasing the contact area between the core and the facesheet the core-to-facesheet bond strength increased.
Shaikh et al
Small wind turbines (SWTs) are a prominent renewable energy technology for decentralized power generation. Blade material and its profile are vital parameters for the aerodynamic performance of SWTs. Traditionally E-glass fibre-reinforced composites (FRCs) are the widely accepted material for developing SWT blades. However, its application is limited by moderate tensile and fatigue properties. Alternatively, other FRC materials such as carbon, basalt and natural fibre composites are proposed as future materials for SWT blades. However, individual materials are observed to satisfy the requirements partially. Therefore, the hybridization of these materials, particularly Glass/Carbon composites is foreseen as a prospective solution for developing cost-competitive and high-strength SWT blades. There are various studies performed to obtain optimized glass/carbon hybrid composites. However, overall material properties required for SWT blades such as low cost, lightweight, moderate flexural strength and higher tensile and fatigue strengths have not been considered simultaneously during the optimization process. This work presents multi-objective optimization of Glass/Carbon hybrid composites using extreme mixture design response surface methodology (RSM) for small wind turbine (SWT) applications. The weight percentages of glass and carbon fibres are optimized to achieve desired material properties for SWT blades. The experiments are planned using extreme mixture design RSM and the regression models for desired material properties are developed with a 95% confidence level. RSM-based desirability function is employed to perform multi-objective optimization. Maximum composite desirability of 93.5% is achieved with optimal proportions of 37.9% and 27.1% for glass and carbon fibres respectively. An adequate tensile, flexural and fatigue strengths of 486.02, 435.41 and 316.27 MPa respectively are obtained for optimized glass/carbon hybrid composite at an optimum cost of 2228.76 Rs/Kg and density of 3.39 g/cm3. The regression models and optimization results are validated through a confirmation experiment with an error of less than 6.1%.
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Anasheh Khecho and Erina Baynojir Joyee 2024 Funct. Compos. Struct. 6 015010
Additive manufacturing (AM) has drawn significant attention in the fabrication of soft actuators due to its unique capability of printing geometrically complex parts. This research presents the design and development of an AM process for bioinspired, deformable, and magnetic stimuli-responsive actuator arms. The actuator arms were fabricated via the material extrusion-based AM process with magnetic particle-polymer composite filaments. Inspired by the rhombus cellular structure found in nature, different design parameters, such as the line width of the interior rhombus sides, and 3D printing parameters were studied and optimized to fabricate actuator arms that exhibit enhanced flexibility while being magnetically actuated. The trigger distance and deformation experiments revealed that the width of the rhomboids' sides played a critical role in magnetic and bending properties. It was found that the sample with a line width of 550 µm and printing layer thickness of 0.05 mm had the maximum deflection with a measured bending angle of 34 degrees. The magnetic property measurement exhibited that the sample with a line width of 550 µm showed the maximum magnetic flux density of 3.2 mT. The trigger distance results also supported this result. A maximum trigger distance of 8.25 mm was measured for the arm with a line width of 550 µm. Additionally, tensile tests showed that the sample exhibited a 17.7 MPa tensile strength, 1.8 GPa elastic modulus, and 1.3% elongation. Based on these results, we successfully fabricated a 3D printed magnetic gripper with two rhombus cellular structured arms which showed grasping and extensive load lifting capability (up to ∼140 times its weight).
S Gowthaman and T Jagadeesha 2024 Funct. Compos. Struct. 6 015002
The existence of cracks and variations in loading direction has invoked greater modifications in the material properties. In this work, the tensile features of cracked and non-cracked FeCr polycrystals have been analyzed under numerous temperatures (300 K, 500 K, 700 K, and 900 K) and loading directions (parallel and normal to the crack cross-sectional directions) through molecular dynamics and it is originated that temperature has raised a higher impact on the tensile features trailed by the existence of crack and loading directions, owing to the formation of larger kinetic energy (KE) amidst the atoms. The existence of crack offers a moderate impression on the tensile behavior followed by the loading direction, due to its dominant impact on the tensile behavior through greater stress concentrations. Additionally, it is stated that the greater temperature along with the existence of crack and loading along normal to the crack cross section offers greater reductions in the tensile features of FeCr polycrystal, owed to the interactive effect of larger KE and discontinuity among atoms. Furthermore, the shear strain and displacement contour map and materials feature also confirm a similar occurrence which leads to altering its material behavior.
Orhan Gülcan et al 2023 Funct. Compos. Struct. 5 022001
Many engineering structures, especially defense applications, need to be reinforced against blast loads due to a nearby explosion. Today, much more attention needs to be given to this issue because of increased exposure to explosions, and natural disasters. Different solutions have been used in the literature to mitigate blast-loading effects. One of these applications, sandwich panels, are a good candidate for blast-loading applications. In a sandwich panel structure, several parameters have considerable effects on deflections, deformations, and energy absorption capability. The most important of these parameters are: (i) the material and thickness of the front and back face sheets and core; (ii) core density and grading; (iii) core and face sheet types; (iv) filling and stiffening strategies of the core; (v) radius of curvature of the panel; (vi) mass of explosive charge; and (vii) standoff distance. The aim of this paper is to review these critical aspects of blast loading of sandwich panels to provide an overall insight into the state of the art of the application.
Chidume Nwambu et al 2022 Funct. Compos. Struct. 4 045001
A dynamic mechanical thermal analyser operating in the single cantilever mode was used to examine the dynamic mechanical properties of unaged and hygrothermally aged discontinuous asymmetric helicoidal (Bouligand) carbon fibre reinforced plastic (CFRP) composites as a function of fibre architecture. The discontinuous Bouligand was manufactured using two major pitch angles as independent variables: 90° and 120° and from each major pitch angle, minor interply pitch angles were used as independent variables ranging 5°–25°. The composites were tested as either dry unaged specimens or following hygrothermal ageing in seawater at the constant temperatures of 40 °C and 60 °C for over 2000 h. We find that the viscoelastic properties E' and E'' are adversely affected by both hygrothermal aging and the minor pitch angle, but not the major pitch angle. Higher hygrothermal ageing temperatures and increasing minor pitch angles are found to decrease the energy absorption and dissipation capacities of discontinuous Bouligand structured CFRP composites. The tan-δ curves also indicate that hygrothermal ageing increases the heterogeneity of discontinuous Bouligand structured composites, with separate viscoelastic phases and glass transition temperatures.
Mohammad Afzali and Vahid Asghari 2022 Funct. Compos. Struct. 4 015002
The purpose of this project was to introduce a way to improve the mechanical properties of dissimilar welded material, which provides benefits such as affordability, high speed, and a suitable bond property. This experimental project applies the friction welding method, including combining parameters, such as a numerical control machine, two different speeds, and three different cross sections, including flat, cone, and step surfaces. When the welding process was done, samples were implemented and prepared via a bending test of materials. The results have shown that, besides increasing the machining velocity, the surface friction increased, and so did the temperature. Considering the stated experimental facts, the melting temperature of composite materials increased. This provides the possibility of having a better blend of nanomaterial compared to the base melted plastics. Thus, the result showed that, besides increasing the weight percentage of nanomaterial contents and machining velocity, the mechanical properties increased on the welded area for all three types of samples. This enhancement is due to the better melting process on the welded area with the attendance of various nanoparticle contents. Also, the results showed that the shape of the welding area could play a significant role, and the results also change drastically where the shape changes. Optimum shape in the welding process has been dedicated to the step surface. The temperature causes the melting process, which is a significant factor in the friction welding process.
Jiwon Jung et al 2021 Funct. Compos. Struct. 3 015006
Coarse-grained molecular dynamics simulations are a widely accepted methodology in the field of studying the viscoelasticity of elastomers. In this paper, a thermophysically balanced multiscale coarse-grained potential for glass-forming polymers is presented with the energy renormalization (ER) method by redefining temperature transferable correlation effects between rescaling factors for energy parameter and length-scale parameter. The correlation effects have not been investigated in the literature, to the best knowledge of authors. The coarse-grained potential was demonstrated for the polyisoprene model generated from the anionic polymerization. The ER enables temperature transferability by adopting renormalization parameters as function of the temperature. Considering the correlation effects, a multi objective-optimization algorithm was adopted to find proper solution sets of and matching mean square displacement (MSD) and density to the all-atom model simultaneously. Meanwhile, shear stress was matched to find first, then, density was fitted in the low-temperature regime. To verify the coarse-grained potential in the middle-temperature regime, MSD was compared to those from the all-atom model, and it was successfully matched.
Pyeong-Su Shin et al 2020 Funct. Compos. Struct. 2 025004
Carbon nanomaterials including, but not limited to, carbon nanotubes (CNTs) and graphene have attracted considerable attention due to their nanoscale electrical conductivity. Flexible sensors have experienced a growing demand due to several potential applications, such as personalized health monitoring and robots. In this study, CNT/cellulose composite sheets were manufactured using spray methods for flexible sensors. MWCNTs were ultrasonically dispersed in an acetone solvent and flexible plain paper was used as a substrate on which the CNT suspension was sprayed. At the end of the coating process, to remove the acetone solvent, the specimens were dried in an oven. Electrical resistance (ER) three-dimensional-mapping and optical observation were used to confirm and evaluate the dispersion of CNTs on the paper. To access the wettability of CNT/cellulose sheets, the changes of static contact angle of distilled water droplets on the sheets were measured. The critical point of the CNT coating numbers was determined using the ER method as well as the change of wettability using the static contact angle measurements.