Lightweight Materials Research Articles

Optimizing Lightweight Material Selection in Automotive Engineering: A Hybrid Methodology Incorporating Ashby’s Method and VIKOR Analysis

The automotive industry is responsible for about 20% of greenhouse gas emissions in Europe, and it is under notable pressure to meet the reduction targets set by the European Union for the next decades. In this context, lightweighting is a very effective design strategy for which materials selection plays a key role. One of the main challenges of lightweighting is selecting materials with enhanced structural properties but a reduced weight in comparison with traditional solutions. The spectrum of available materials is very large, and the choice needs to be carefully evaluated based on multiple factors, such as mechanical behavior, raw materials cost, the availability of manufacturing processes, and environmental impact. This article presents an innovative methodology for materials selection in the lightweight automotive field based on the Ashby approach for mechanical performance coefficients as an initial filtering criterion. Following this preliminary screening, this study adopts the VIKOR (Vise Kriterijumska Optimizacija I Kompromisno Resenje) MCDA (Multi-Criteria Decision Analysis) technique to rank feasible design solutions based on case study boundary conditions. The evaluation criterion of different design options encompasses crucial factors, such as mechanical properties, cost considerations, and environmental impact measures. The method is finally validated by the application of a redesign case study, a motor bracket of an electric commercial car.

Lightweight MXene Composite Films with Hollow Egg-Box Structures: Enhanced Electromagnetic Shielding Performance Beyond Pure MXene.

MXene is widely used in the electromagnetic interference (EMI) shielding field. However, the high electromagnetic reflectivity of pure MXene causes potential secondary EMI pollution. This study presents a hollow egg-box structure used in MXene composite film, by which the reflectivity (R) could decrease from 0.98 to 0.54 and absorbance (A) increased from 0.02 to 0.45, effectively decreasing the high electromagnetic reflectivity of pure MXene. Additionally, compared to pure MXene films, the MXene composite films exhibit improved electromagnetic interference shielding effectiveness (EMI SE) and SSE/t. The prepared films achieve a peak EMI SE of 69.19 dB at 12.4 GHz, which is 1.3 times higher than pure MXene, and a peak SSE/t of 27 888 dBcm2g⁻¹ at 12.4 GHz, 1.4 times that of pure MXene. The hollow egg-box structure not only enhances the electromagnetic shielding performance beyond pure MXene but also demonstrates outstanding performance compared to most reported MXene films, balancing lightweight material properties with effective shielding. Furthermore, the prepared MXene composite films with the hollow egg-box structure show improved water resistance. Therefore, MXene composite films with hollow egg-box structures are promising candidates for advanced EMI devices in future lightweight materials.

Investigation into high-speed impact response of composite sandwich structures

Sandwich structures composed of top and bottom face sheets and an inner core are commonly used for energy-absorbing applications, mainly because of their superior stiffness-to-weight ratio and crashworthiness. Despite extensive studies on the ballistic behavior of monolithic and composite materials, limited research has focused on hybrid sandwich structures combining lightweight and ductile materials like thermoplastic polyurethane (TPU) with high-strength aluminum. This study aimed to numerically establish the ballistic limit velocities and the penetrating and perforation resistances of composite sandwich structures to address this gap. The sandwich panels were manufactured from thermoplastic polyurethane (TPU) and aluminum (Al) 2024-T351 as core and face sheets/skins, respectively. The panels were subjected to an impact to investigate the effects of various thicknesses of their face skins and core on high-speed impact resistance. From the results obtained, it was evident that the numerical models simulated experiments with high accuracy. The impact and damage resistances of the composite sandwich structures increased with the thicknesses of their core and face sheets. The resistance of the structure increased by 19% by increasing the thickness of face sheets from 1.2 to 2.0 mm. Similarly, the resistance of the composites can be increased by 44% by increasing the core thickness from 20 to 50 mm. Therefore, it can be established that the impact resistance of the composite sandwich structures depended on the thicknesses of their core and skins. The investigated performances of the different composite sandwich structures should guide their choice for various industrial applications.

Radiation protection: assessing the shielding performance of iron-reinforced polydimethylsiloxane in comparison to lead

Abstract This study evaluates the radiation shielding properties of Polydimethylsiloxane reinforced with iron. Using the Py-MLBUF program, we calculated and compared the mass attenuation coefficient, linear attenuation coefficient, half-value layer, effective atomic number, and effective electron number with those of lead. The dominance of the photoelectric effect at lower energies and pair production at higher energies is observed. The contribution of Compton scattering remains relatively constant across the energy spectrum, while Rayleigh scattering is negligible. At lower energy levels, composites reinforced with higher iron weight fractions demonstrate higher mass attenuation and linear attenuation coefficients. Increasing iron weight fractions reduces the half-value layer, improving radiation attenuation up to a threshold. The results show that while lead generally has higher attenuation coefficients, the difference is negligible at energies between 0.7 and 4 MeV. Although lead has lower half-value and tenth-value layers, higher iron weight fractions in PDMS also, provide good radiation shielding due to increased effective atomic and electron numbers. Fe-reinforced PDMS at weight fractions of 10%, 20%, 40%, and 60% show significant potential for radiation shielding, especially in the 0.7 to 4 MeV photon energy range, and in applications requiring flexibility and lightweight materials.

Research on Human-Machine Interaction Control Technology for Lower Limb Exoskeleton Rehabilitation Robots

In response to the health assurance challenges faced by the elderly population in Chinas aging society and to mitigate the shortage of medical resources while improving the rehabilitation rate of patients with central nervous system injuries, research on lower limb exoskeleton rehabilitation robots has been widely conducted. Since the 1960s, countries such as Switzerland, the United States, the Netherlands, Germany, Japan, and China have successively developed relatively mature standing and recumbent lower limb exoskeleton systems. This paper builds the kinematic and dynamic models of a lower limb exoskeleton rehabilitation robot based on a two-link mechanism, laying the theoretical foundation and implementation approach for processing position, velocity, and torque sensor signals in human-machine interaction control. Based on domestic and international progress as well as kinematic and dynamic analysis, four types of human-machine interaction control technologiestrajectory tracking control, force-position hybrid control, impedance control, and bioelectrical signal controlare thoroughly analyzed, providing a technical framework for engineering implementation. In the future, lower limb exoskeleton rehabilitation robots will integrate lightweight materials and structural design, intelligent adaptive algorithms, and environmental perception technologies, utilizing low-cost open-source platforms to optimize human-machine interaction control technology for more efficient, safe, and personalized rehabilitation training

Taming the Flow with Hyperbranched Polyamides as Melt Modifiers in Polyamide Composites.

Transport equipment manufacturers in the automotive and aerospace industries are focused on developing materials that enhance fuel efficiency and reduce carbon dioxide emissions. A significant approach is employing lightweight materials like aluminum, magnesium, and polymer-based composites. Polyamide-based composites, particularly nylon 66, as viable alternatives due to their excellent rigidity, chemical resistance, and thermal stability are investigated to address the limitations of traditional thermosetting resins, which are difficult to recycle and have lengthy molding processes that hinder mass production. This research aims to create a polymer additive that lowers melt viscosity during high-temperature processing, thereby improving the processability of these composites. Hyperbranched polyamides (HBPs) with a dendritic structure and numerous terminal groups, which offer lower melt viscosity and greater solubility than linear polymers, are synthesized. By disrupting intermolecular bonds within PA66, these HBPs are expected to enhance miscibility and act as internal slip agents and melt-modifier. Using the A2+B3 approach, novel-hyperbranched polyamides are produced from commercially available monomers, allowing for better industrial applicability. The resulting composites demonstrate improved dispersion, reduced melt viscosity, and high-thermal stability, highlighting their potential as effective melt modifiers for engineering plastics in lightweight composite applications.

Lightweight and Mechanically Robust Cellulosic Triboelectric Materials for Wearable Self-Powered Rehabilitation Training.

Lightweight and robust self-powered wearable devices are of great importance in rehabilitation and medical assistance, but this places greater demands on the development of functional materials. In particular, a balance between reducing the weight of materials and enhancing their mechanical performance is urgently needed. Here, this study reports a design strategy based on a cross-scale strengthening mechanism, which endows triboelectric materials with mechanically robust properties, and can withstand more than 16,600 times its weight without any deformation. A biomimetic ordered network structure with "wall-septum" is obtained by using the directional ice templating method, followed by the formation of more hydrogen bonds between polymer molecular chains promoted by salting-out. The resultant triboelectric material exhibits a Young's modulus of 130.3 MPa, and a specific modulus of 409.0 kN m/kg. Triboelectric materials are used to construct highly robust triboelectric nanogenerators that are stable even under an impact of 735.5 kPa. The accurate acquisition of a human motion state signal in the process of rehabilitation training is realized. This study provides a universal strategy for the development of lightweight and robust triboelectric material and provides a solution for the application of self-powered wearable devices in rehabilitation training.

Polyurethane nickel lacquer coated carbon fiber cloth with excellent mechanical properties and high electromagnetic shielding performance

With the development of electronic information and communication technology, electromagnetic waves are everywhere in our lives, so there is an urgent need to develop efficient electromagnetic shielding (EMI) materials to reduce electromagnetic wave pollution. Medical devices, 5G communications, aerospace and other fields require materials that are tough and durable, flexible and thin, have excellent mechanical properties and high-efficiency electromagnetic shielding properties to meet practical needs. In this study, polyurethane (Pur), a lightweight, wear-resistant and stable polymer material, was combined with nickel paint and applied to the surface of 3 k carbon fiber cloth using a tension-pressing machine under high pressure to form a single-sided electromagnetic shielding composite material. Experimental verification shows that the composite sample C5P5CP made by adding 50 wt% polyurethane (Pur) and 50 wt% nickel paint has stable and efficient electromagnetic shielding performance in the entire X-band (8–12 GHz), with an average electromagnetic shielding value of 60 dB. It can exhibit excellent friction performance under variable load friction of 1, 3, 5, 7 and 9 N, and shows the best corrosion resistance in electrochemical experiments. Electromagnetic wave absorption is the main way composite materials shield against electromagnetic waves. This reduces the harm from secondary reflections. The material has a simple manufacturing process and excellent mechanical properties, including lightness, flexibility, and wear resistance. Its efficient electromagnetic shielding performance offers new ideas for designing shielding materials in various fields, and it is expected to have practical applications.

COOLING EFFECT OF DIFFERENT TYPES OF MATERIALS IN AN AVIONICS SYSTEM

Equipment used in the aviation industry heats up over time depending on working conditions. It is possible to preserve properties of equipment affected by heat by either cooling the system and returning it to initial conditions or producing the system from materials that are not affected by heat. One of the areas where nanocomposite materials might be used is avionic systems in the aviation and space industry. These systems are structures in which elements such as sensors, cabling, and processors, which form the basis of the electronic structure of flight, are brought together in very small volumes. It is important that the material used in these structures is light and has high strength as well as corresponding electromagnetic properties. In this study, the thermal analysis of vapor-grown carbon fiber (VGCF) nanocomposite materials produced by adding them to the epoxy matrix in terms of the thermal performance of avionic boxes was carried out by comparing them with thermal properties of aluminum. As a result of the findings obtained from thermal analysis studies carried out in four stages, it was observed that by using VGCF composite instead of aluminum, approximately 23% improvement in temperature output and 17% improvement in thermal load was achieved. Another outcome obtained from the analysis was the cooler capacity. If VGCF is preferred instead of aluminum in avionics box manufacturing, a 37.5% improvement is achieved in terms of cooler capacity. Another important finding is the time to reach critical temperature levels. VGCF reaches the steady state 163.5% faster than aluminum. Thus, it is anticipated that energy efficiency will be increased with the use of lightweight and high-strength nanocomposite materials, which is considered one of the most important goals of the aviation industry.

Lightweight, strong, and sound insulation bio-based structural material from discarded coconut wood

Lightweight, strong, and sound insulation bio-based structural material from discarded coconut wood

Conjugated core-shell bottlebrush polymers that exhibit crystallization-driven self-assembly.

Bottlebrush polymers are complex architectures with densely grafted polymer side chains along polymeric backbones. The dense and conformationally extended chains in bottlebrush polymers give rise to unique properties, including low chain entanglement, low critical aggregation concentrations, and elastomeric properties in the bulk phase. Conjugated polymers have garnered attention as lightweight, processible, and flexible semi-conducting materials. They are promising candidates in electronic devices and sensors, but their optoelectronic properties depend on adequate polymer ordering, π-π interactions, and crystallization. Crystallization-driven self-assembly of conjugated polymers has become a prominent method to optimize properties including band energies, redox potentials, and exciton diffusion and transport. Much progress has been made in controlled block copolymer self-assembly, but despite their promising properties, reports of conjugated bottlebrushes have been limited, and their self-assembly is relatively unexplored. For the first time, we report the synthesis of conjugated core-shell bottlebrush polymers. These materials contain poly(3-hexylthiophene) (P3HT) and poly(ethylene glycol) (PEG) in either core or shell position. We demonstrate that the use of P3HT as a crystallizable conjugated polymer and PEG as a colloidally stabilizing and disaggregating block facilitates their self-assembly into a number of unique crystalline morphologies with longer conjugation lengths and lower exciton bandwidths relative to analogous diblock copolymers. These include intramolecularly self-assembled segregated bottlebrush polymers, short nanofibers formed by end-on-end stacking of bottlebrush molecules, extremely long >20 μm nanofibers formed exclusively by end-on-end stacking, and >15 μm nanoribbons formed from both end-on-end and side-by-side stacking of bottlebrush polymers.

Shola: a 3D porous hydrophobic–oleophilic lignocellulosic material for efficient oil/water separation

Shola, a natural shrub abundant in Bengal (India), has been used for centuries to make decorative crafts for social and religious ceremonies. It was found to be a highly porous and lightweight material composed of predominantly amorphous cellulose and a useful sorbent for removing oil from water.

Lightweight Resources for automobiles manufacturing

Automakers are now motivated to create lightweight vehicles due to the increasing challenges of reducing greenhouse gas emissions and improving fuel economy. Better recyclability and/or vehicle performance may also result from the weight reduction. The expansion and use of lightweight, high-performance resources as substitutes for traditional motorized materials like steel and cast iron is one successful tactic. This paper discusses vehicle lightweighting as a means of promoting better fuel economy and assisting the automotive industry in achieving sustainability. Innovative resources suitable for the constructing of next generation vehicles were reviewed. Advanced high-strength steel (AHSS), aluminum alloys, magnesium alloys, Titanium, polymers, and composite materials frequently utilized for lightweight construction applications were among the cutting-edge materials for the production lightweight vehicles. Categorization, manufacturing methods, physical/mechanical characteristics, and possible uses of lightweight ingredients are investigated. A summary of the reviewed materials' benefits and limitations is provided, along with the suitable application scenarios for various lightweight materials.

Nanosized κ-Carbide and B2 Boosting Strength Without Sacrificing Ductility in a Low-Density Fe-32Mn-11Al Steel.

High-performance lightweight materials are urgently needed because of energy savings and emission reduction. Here, we design a new steel with a low density of 6.41 g/cm3, which is a 20% weight reduction compared to the conventional steel. The mechanical properties and microstructures of the steels prepared with different routes are systematically explored by utilizing uniaxial tensile testing and transmission electron microscopy. The steel processed by cold rolling and recrystallization annealing at 950 °C for 15 min shows an ultra-high yield strength of 1241 ± 10 MPa, while retaining a good ductility of 38 ± 1%. The high yield strength is mainly related to the synergistic precipitation strengthening introduced by nanoscale B2 and κ'-carbides. It is encouraging to notice that the yield strength increased without scarifying ductility, compared to the ST steel. The key reason is that the high strain hardening rate is activated by combined factors, including the blockage of numerous twins and nanoscale B2 to the dislocation movements, and dynamic slip band refinement. This study is instructive for concurrently enhancing the strength and ductility of austenitic lightweight steels with fully recrystallized grains and dual nano-precipitates.

Effect of Post-Processing on the Microstructure of WE43 Magnesium Alloy Fabricated by Laser Powder Directed Energy Deposition

Additive manufacturing of magnesium (Mg) alloys is of interest for the fabrication of complex-shaped lightweight materials. This study evaluates the microstructure of WE43 Mg alloy deposited using laser powder directed energy deposition (LPDED) additive manufacturing technique in as-deposited and post-processed conditions. As-deposited samples exhibited roughly 2% porosity, which was reduced to below 0.1% after hot isostatic pressing. Despite limited grain growth after heat treatment, some grains experienced abnormal grain growth, likely due to Zener pinning and non-uniform dissolution of grain boundary precipitates. Moreover, as-deposited specimens contained Nd-rich grain boundary precipitates which dissolved during post-processing. Additionally, during heat treatment. a fine distribution of needle-like β1 or β precipitates formed. Overall, the precipitate size and distribution following heat treatment was non-uniform, likely because of the non-uniform response of the LPDED material to heat treatment, owing to the variation in local- and global-temperature profiles during deposition. Furthermore, arc-shaped phases with a high concentration of Y, O, and Zr were present for all processing conditions and are associated with the passivation of the feedstock powder prior to deposition. Moreover, an equiaxed-grain structure with a random orientation and a finer grain size in the regions adjacent to the arc-shaped phases was observed in all processing conditions.

Enhancing in‐plane elasticity of carbon fiber reinforced thermoplastic multilayer films with polyrotaxane and nanocellulose composites

AbstractSandwich films were prepared by inserting resin sheets between carbon fiber‐reinforced thermoplastic (CFRTP) sheets, and their tensile and bending strengths were evaluated. The CFRTP sheets used nylon 66, polyurethane, and polyphenylene sulfide as impregnating resins. The resin sheet used was polypropylene, a general‐purpose resin, combined with a composite material incorporating polyrotaxane and cellulose nanofibers as organic fillers. The sample containing both components showed a 134% improvement in Young's modulus compared to neat polypropylene. This study controlled the number of layers in the sandwich film and assessed the dependence of mechanical properties on layer count. The sandwich films demonstrated particularly good strength in the in‐plane direction, exhibiting excellent bending properties. Furthermore, using composite materials for the resins sandwiched between CFRTP sheets further enhanced mechanical properties. The film material, which can be prepared through simple press molding, is a lightweight material composed of light elements, and exhibits a Young's modulus in the gigapascal scale. CFRTP sheets using nylon 66 as the impregnating resin, the flexural modulus improved by approximately 5.8 times. Furthermore, by increasing the number of laminations, an additional improvement of 3.1 times was observed. This study also identified conditions for improving elongation properties.Highlights A new material was created using carbon fiber reinforced thermoplastics (CFRTP). Multilayered alternating films made of CFRTP and polymer composite were created. Corresponding multilayer films showed anisotropy in mechanical properties. Corresponding multilayer films exhibited excellent in‐plane elasticity. In‐plane elasticity showed a clear dependency on the number of layers.

Nanotechnology-Enabled Innovations in High-Strength Lightweight Vehicle Design for Enhanced Safety and Energy Efficiency

Global warming and resource depletion are two of the most pressing issues confronting modern society, with the automotive industry being a significant contributor to energy consumption and environmental impact. Additionally, rising fatalities from traffic accidents have highlighted the need for improved vehicle safety. This paper explores the transformative role of nanotechnology in developing high-strength, lightweight materials that enhance both vehicle safety and fuel efficiency. By incorporating nanocomposites, known for their low density, superior strength, heat resistance, and scratch resilience, vehicles can achieve significant weight reductions without compromising performance. These advancements reduce vehicle failure rates, increase passenger survival in accidents, and contribute to energy savings, whether in electric or internal combustion engine vehicles. The paper also discusses the potential of lightweight vehicles in reducing fuel consumption and carbon emissions, making them key players in combating climate change and addressing resource shortages. Through a comprehensive analysis of nanotechnology’s impact on material science, this study highlights its critical role in shaping the future of sustainable vehicle design.

Development and Applications of Polypyrrole‐Based Conductive Inks: An Overview

AbstractDue to their flexibility, high conductivity, stability, monodispersity, and ease of processing; polypyrrole‐based conductive inks hold significant advancements in printing, biomedical and electronic applications. These inks enable innovative solutions in flexible electronics, wearable devices, sensors, and energy storage systems and also facilitate high‐quality printed films on various rigid and flexible substrates, supporting diverse applications from flexible circuits to smart textiles. Notably, in biomedicine, they exhibit excellent biocompatibility, and cell adhesion, aiding in tissue engineering and stem cell therapies. They serve as bioinks for 3D printing free‐standing scaffolds, showing potential for creating electrically active tissue constructs. Additionally, polypyrrole inks are crucial for developing highly specific and sensitive sensors for detecting gases, chemicals, and biological analytes and efficient energy storage devices like supercapacitors. As research progresses, these inks are pivotal in the future of lightweight, flexible, portable, and wearable electronic materials and devices. This review covers a general overview of various types of polypyrrole‐based conductive inks, highlighting their major applications and impacts.

Revolutionizing automotive lightweighting: a comparative analysis of electromagnetic free forming for clamped sheets

Reducing vehicle mass is a critical strategy for enhancing fuel economy and meeting the growing demand for lightweight materials in the automotive industry. Aluminum alloys have emerged as a promising solution due to their low density, but their limited formability compared to steel poses significant challenges. Electromagnetic Forming (EMF) is a high-speed process capable of significantly improving the formability of aluminum alloy sheets, enabling the production of lightweight structural components for automotive applications. This process operates within microseconds, which provides a unique advantage for rapid and efficient manufacturing. The numerical modeling of EMF plays a pivotal role in understanding the complex physics and deformation behaviors associated with this process. This research investigates the numerical modeling of EMF for various aluminum alloy sheets using a spiral coil. The results provide insights into the distinctive deformation behaviors and performance variations of different alloys under identical process conditions, which offers valuable guidance for material selection and process optimization in automotive applications.

Effect of Vanadium and Austempering Parameters on the Microstructure and Mechanical Properties of Austempered Ductile Iron (ADI) for Tricycle Crankshaft Applications

This research focused on the excellent mechanical properties of austempered ductile iron (ADI) which have been harden to significantly increase its application in the production of automobile parts, and improve their performance. ADI has been produced in this work to replace forged steel crankshaft taking advantage of the significant savings in energy, and the resulting advancement of lightweight and durable material. The suitability of calcined periwinkle ash, as an alternative to ferrosilicon-magnesium, as a nodularizer in ductile iron treatment, was investigated. Varied compositions of calcined periwinkle at 600°C, were used in the treatment of different chemical compositions of molten metal. Response surface methodology – Version 17 of the MINITAB two-level full fractional design 2k-1 + 2k+6 giving 30 research runs (castings) was employed in this study. Also, Molybdenum, Vanadium, Copper, and calcined periwinkle ash as alloying additives at various concentrations was considered. Results show that the 5.5wt.% calcined periwinkle ash that produces good graphite nodules and high nodularity in sample N comprising 3.58% C, 2.60% Si, 0.27% Mn, 0.027% Cr, 0.0098% S, 0.023% P, 0.3% Cu, 0.3% V and 0.2% Mo provided the best mechanical properties. The values obtained were within limits obtained by previous researchers in accordance with the American Society for Testing and Materials (ASTM) A897 130-90-09 standards.