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Advancements in additive manufacturing have significantly increased the use of cellular structures in product development, especially in the automotive, aerospace, and biomedical industries, due to their enhanced strength-to-weight ratio and energy-absorbing capabilities. This study investigates the tensile properties of 3D-printed PLA prismatic cellular structures, focusing on the effects of fillet radius, wall thickness, and cell size on tensile strength, Young’s modulus, and strength-to-weight ratio. Using a full factorial design and ANOVA, we examined the impact and interaction of each geometrical parameter. Our findings show that triangular cellular structures exhibit a higher stiffness of 1.36 GPa and tensile strength of 24.28 MPa, resulting in a notable 5.78 MPa/gram strength-to-weight ratio. Increasing cell count and wall thickness enhances both tensile strength and Young’s modulus, whereas adding fillet radii at corners reduces these properties. Fracture behaviors are influenced by geometrical design: shorter, thicker walls lead to progressive crack propagation, while longer, thinner walls tend to fail catastrophically. Fillet radius introduction shifts the fracture initiation point from the nodes. ANOVA results indicate that wall thickness and cell size significantly affect tensile strength and Young’s modulus, contributing 36.53% and 53.54%, respectively.

Cold-formed steel section (CFS) is broadly utilised in structural elements such as compression members, flexural members and tension members. Owing to its commendable properties such as light weight, easy handling, faster installation, aesthetic appearance and high strength to weight ratio, this study investigates the impact of lip depth and web depth on the flexural strength of light gauge steel C-sections. Specifically, it examines the flexural strength, including the strength-to-weight ratio, of C-sections with varying lip depths, and comparing these trends across different web depths. A finite element analysis was carried out to determine the optimum dimension of the depth of the lip by using the software ABAQUS. Load–deflection behaviour, failure modes, strength to weight ratio and changes in the load carrying capacity were discussed in this paper. The paper explores the load–deflection behaviour, failure modes, strength-to-weight ratio variations and corresponding differences in bending carrying capacity. The analysis reveals that the strength-to-weight ratio of C-sections increases gradually with lip depth. Moreover, an increase in lip depth positively influences the load carrying capacity of lipped channel sections in CFS structures.

Composites have been found to be the most promising and discerning material available in this century. Presently, composites reinforced with fibers of synthetic or natural materials are gaining more importance as demands for lightweight materials with high strength for specific applications are growing in the market. Fiber-reinforced polymer composite offers not only high strength to weight ratio, but also reveals exceptional properties such as high durability; stiffness; damping property; flexural strength; and resistance to corrosion, wear, impact, and fire. These wide ranges of diverse features have led composite materials to find applications in mechanical, construction, aerospace, automobile, biomedical, marine, and many other manufacturing industries. Performance of composite materials predominantly depends on their constituent elements and manufacturing techniques, therefore, functional properties of various fibers available worldwide, their classifications, and the manufacturing techniques used to fabricate the composite materials need to be studied in order to figure out the optimized characteristic of the material for the desired application. An overview of a diverse range of fibers, their properties, functionality, classification, and various fiber composite manufacturing techniques is presented to discover the optimized fiber-reinforced composite material for significant applications. Their exceptional performance in the numerous fields of applications have made fiber-reinforced composite materials a promising alternative over solitary metals or alloys.

This study presents light metal alloys used in the aeronautical industry, specifically focusing on their suitability for Friction Stir Welding (FSW) and Friction Stir Processing (FSP). These innovative techniques play an important role in improving the mechanical properties and performance of aluminum, magnesium, and titanium alloys, which are extensively utilized in aerospace applications due to their superior strength-to-weight ratios. FSW and FSP offer significant advantages in joining and processing materials, including enhanced weld integrity, defect reduction, and refined microstructural properties. The integration of light metal alloys by these methods within the aeronautical sector fosters the production of lighter and stronger structures, contributing to reduced fuel consumption and improved overall performance in aeronautical engineering.

Aluminum matrix composites (AMCs) developed with micro/nano-reinforcements emerge as an attractive candidate for innumerable applications, including automotive, aerospace, electronics, biomedical, and many more, owing to their high strength-to-weight ratio and outstanding tribological, mechanical, electrical, and thermal characteristics. This work aims to offer a review of the state of the art of research in the processing, fabrication, properties, and potential applications of AMCs. The review starts with an emphasis on light-weighted AMCs, followed by a brief discussion of the hybrid metal matrix composite structure and micro/nano-reinforcement. This review also includes an in-depth assessment of manufacturing processes and parametric factors that regulate the properties of AMCs. It also highlights the challenges that are currently encountered when processing AMCs, such as limited wettability, reinforcement agglomeration, and interfacial reactions, before analyzing the effect of adding micro/nano-reinforcements on the attributes of AMCs. In addition to the stated characteristics, the most feasible and novel applications of AMCs have been envisioned. Lastly, new research directions in the field of AMCs have been recommended and critically discussed.

Cellular structures are made up of an interconnected network of plates, struts, or small unit cells and acquire many unique benefits such as, high strength-to-weight ratio, excellent energy absorption, and minimizing material requirements. When compared with the complicated conventional processes, additive manufacturing (AM) technology is capable of fabricating geometries in almost all types of shapes, even with the small cellular structures inside, by adding material layer-by-layer directly from the digital data file. All major industries have been exploiting the benefits of cellular structures due to their prevalence over a wide range of research fields. To date, there are a few state-of-the-art reviews compiled focusing on a specific area of lattice structures, but many aspects still need to be reviewed. Therefore, this paper aims to provide a comprehensive review of the various lattice morphologies, design, and the AM of the cellular structures. Furthermore, the superior properties of the additively fabricated structure, as well as the applications and challenges, are presented. The conducted review has identified the significant limitations and gaps in the existing literature and has highlighted the areas that need further research in the design, optimization, characteristics, and applications, and the AM of the cellular structures. This review would provide a more precise understanding and the state-of-the-art of AM with the cellular structures for engineers and researchers in both academia and industrial applications.

This review analyses the design, mechanical behaviors, manufacturability, and application of gradient lattice structures manufactured via metallic additive manufacturing technology. By varying the design parameters such as cell size, strut length, and strut diameter of the unit cells in lattice structures, a gradient property is obtained to achieve different levels of functionalities and optimize strength-to-weight ratio characteristics. Gradient lattice structures offer variable densification and porosities; and can combine more than one type of unit cells with different topologies which results in different performances in mechanical behavior layer-by-layer compared to non-gradient lattice structures. Additive manufacturing techniques are capable of manufacturing complex lightweight parts such as uniform and gradient lattice structures and hence offer design freedom for engineers. Despite these advantages, additive manufacturing has its own unique drawbacks in manufacturing lattice structures. The rules and strategies in overcoming the constraints are discussed and recommendations for future work were proposed.

The use of the friction stir welding (FSW) process as a relatively new solid-state welding technology in the aerospace industry has pushed forward several developments in different related aspects of this strategic industry. In terms of the FSW process itself, due to the geometric limitations involved in the conventional FSW process, many variants have been required over time to suit the different types of geometries and structures, which has resulted in the development of numerous variants such as refill friction stir spot welding (RFSSW), stationary shoulder friction stir welding (SSFSW), and bobbin tool friction stir welding (BTFSW). In terms of FSW machines, significant development has occurred in the new design and adaptation of the existing machining equipment through the use of their structures or the new and specially designed FSW heads. In terms of the most used materials in the aerospace industry, there has been development of new high strength-to-weight ratios such as the 3rd generation aluminum–lithium alloys that have become successfully weldable by FSW with fewer welding defects and a significant improvement in the weld quality and geometric accuracy. The purpose of this article is to summarize the state of knowledge regarding the application of the FSW process to join materials used in the aerospace industry and to identify gaps in the state of the art. This work describes the fundamental techniques and tools necessary to make soundly welded joints. Typical applications of FSW processes are surveyed, including friction stir spot welding, RFSSW, SSFSW, BTFSW, and underwater FSW. Conclusions and suggestions for future development are proposed.

Alloying steel with aluminium improves the material’s strength-to-weight ratio, but the resulting formation of brittle intermetallic compounds within the steel matrix reduces its ductility; here the morphology and distribution of the intermetallic precipitates are controlled to alleviate this problem. Steel that's lighter — but stronger Despite having long been the metals of choice for many structural applications, iron and steel suffer from relatively low strength-to-weight ratios (specific strength). This has driven interest in the development of high-aluminium low-density steels, but such alloys tend to have poor ductility because of the formation of brittle precipitates within the steel matrix. Efforts have been made to suppress the formation of these precipitates, but now Sang-Heon Kim and colleagues show how instead their morphology and distribution in the matrix can be controlled to alleviate their undesirable influence on ductility. The resulting steel has a combination of specific strength and ductility that goes beyond that of titanium alloys, the lightest, strongest metallic materials known. As lightweight steel is also cheaper than titanium, the future for this new alloy could be bright. Although steel has been the workhorse of the automotive industry since the 1920s, the share by weight of steel and iron in an average light vehicle is now gradually decreasing, from 68.1 per cent in 1995 to 60.1 per cent in 2011 (refs 1 , 2 ). This has been driven by the low strength-to-weight ratio (specific strength) of iron and steel, and the desire to improve such mechanical properties with other materials. Recently, high-aluminium low-density steels have been actively studied as a means of increasing the specific strength of an alloy by reducing its density 3 , 4 , 5 . But with increasing aluminium content a problem is encountered: brittle intermetallic compounds can form in the resulting alloys, leading to poor ductility. Here we show that an FeAl-type brittle but hard intermetallic compound (B2) can be effectively used as a strengthening second phase in high-aluminium low-density steel, while alleviating its harmful effect on ductility by controlling its morphology and dispersion. The specific tensile strength and ductility of the developed steel improve on those of the lightest and strongest metallic materials known, titanium alloys. We found that alloying of nickel catalyses the precipitation of nanometre-sized B2 particles in the face-centred cubic matrix of high-aluminium low-density steel during heat treatment of cold-rolled sheet steel. Our results demonstrate how intermetallic compounds can be harnessed in the alloy design of lightweight steels for structural applications and others.

The success of oil-based plastics and the continued growth of production and utilisation can be attributed to their cost, durability, strength to weight ratio, and eight contributions to the ease of everyday life. However, their mainly single use, durability and recalcitrant nature have led to a substantial increase of plastics as a fraction of municipal solid waste. The need to substitute single use products that are not easy to collect has inspired a lot of research towards finding sustainable replacements for oil-based plastics. In addition, specific physicochemical, biological, and degradation properties of biodegradable polymers have made them attractive materials for biomedical applications. This review summarises the advances in drug delivery systems, specifically design of nanoparticles based on the biodegradable polymers. We also discuss the research performed in the area of biophotonics and challenges and opportunities brought by the design and application of biodegradable polymers in tissue engineering. We then discuss state-of-the-art research in the design and application of biodegradable polymers in packaging and emphasise the advances in smart packaging development. Finally, we provide an overview of the biodegradation of these polymers and composites in managed and unmanaged environments.