In this review, previous studies about the properties and applications of natural fiber composites in the aerospace and automobile fields will be discussed. Natural fiber composites are a better alternate to the existing artificial fiber composites due to their advantages, e.g. lightweight, cheaper and, most importantly, their environmental aspects and biodegradability. Since ancient times, natural fibers have been used for preparing walls, baskets, ropes, clothes, and many more products. More recently, natural fibers such as jute, kenaf, sisal, hemp, and flax have been used in the engineering production field. Natural fiber composites are used increasingly in the aerospace and automotive industries. Nowadays, natural fiber composites and artificial composites are being compared by researchers to find the most appropriate materials for engineering fields. Researchers are also more focused on natural fibers due to their biodegradability and low production cost. Assessments of the materials used in aircraft parts and panel structures have been made to study the potential of using natural fiber composites instead.

The aim of this study to analyze the effects of the stacking sequence of kenaf and jute fibers on the tensile and flexural properties of the kenaf/jute hybrid composites. Kenaf/jute/kenaf (K/J/K), jute/kenaf/jute (J/K/J) and neat epoxy (EP) composites were prepared using the hand lay-up technique while maintaining total fiber loading of 30 wt%. Mechanical properties were analyzed by using Instron Universal Testing machines. The obtained results showed that the K/J/K hybrid composites exhibited the highest tensile strength (43.21 MPa) and flexural strength (75.57 MPa) as compared with J/K/J hybrid composites. K/J/K hybrid composites also display better tensile and flexural modulus of 3.60 GPa and 4.63 GPa, respectively, as compared to J/K/J hybrid and neat epoxy composites. The morphological properties of tensile and flexural fracture samples of the hybrid composites were analyzed by using scanning electron microscopy (SEM). It’s clear from SEM that fiber pull-out, and matrix cracks occurs in all composites, but K/J/K hybrid composites display better fiber/matrix interfacial bonding. We concluded from this work that layering sequence plays an important role in the mechanical performance of hybrid composites and attributed that fabricated hybrid composites can be used in engineering application such as interiors for aircrafts and automotive.

Metal alloys like stainless steel, titanium, and cobalt-chromium alloys are preferable for bio-implants due to their exceptional strength, tribological properties, and biocompatibility. However, long-term implantation of metal alloys can lead to inflammation, swelling, and itching because of ion leaching. To address this issue, polymers are increasingly being utilized in orthopedic applications, replacing metallic components such as bone fixation plates, screws, and scaffolds, as well as minimizing metal-on-metal contact in total hip and knee joint replacements. Ceramics, known for their hardness, thermal barrier, wear, and corrosion resistance, find extensive application in electrochemical, fuel, and biomedical industries. This review delves into a variety of biocompatible materials engineered to seamlessly integrate with the body, reducing adverse reactions like inflammation, toxicity, or immune responses. Additionally, this review examines the potential of various biomaterials including metals, polymers, and ceramics for implant applications. While metallic biomaterials remain indispensable, polymers and ceramics show promise as alternative options. However, surface-modified metallic materials offer a hybrid effect, combining the strengths of different constituents. The future of biomedical implant materials lies in advanced fabrication techniques and personalized designs, facilitating tailored solutions for complex medical needs.

This review provides a thorough review on nanosilica as a strengthening component in epoxy composites, with a specific emphasis on its suitability for use in aerospace applications. The study commences by examining the distinctive characteristics of nanosilica, encompassing its methods of synthesis as well as its efficacy in augmenting the mechanical and thermal properties of epoxy-based composites. A substantial part of the review focuses on assessing the efficiency of nanosilica-reinforced glass fiber composite laminates, particularly in the field of aerospace structural applications. The issue of low toughness in epoxy composites, specifically the occurrence of crack growth and propagation when subjected to stress, is tackled through the investigation of different toughening techniques. These techniques involve the addition of nanosilica and liquid rubber tougheners such as ETBN. In addition, this review presents the techniques used to distribute nanosilica particles within epoxy resins and offers a detailed examination of the mechanical testing and characterization methods employed for these nanocomposites. The study determines that nanosilica, owing to its substantial surface area and mechanical durability, greatly improves the resilience and overall mechanical efficacy of epoxy composites, rendering it a highly promising material for the aerospace sector. This study suggests that addition of nanosilica in epoxy-based composites until 5% by weight gives the best possible outcomes with respect to increment in mechanical properties like modulus, strength, and toughness.

The main objective of this study is to examine the impact of reinforcements on the strength of natural fiber composites. Recent advancements in natural fiber composites have minimized the usage of man-made fibers, especially in the field of structural applications such as aircraft stiffeners and rotor blades. However, large variations in the strength and modulus of natural fiber degrade the properties of the composites and lower the safety level of the structures under dynamic load. Without compromising the safety of the composite structure, it is significant to enrich the strength and modulus of natural fiber reinforcement for real-time applications. The strength and durability of natural fiber can be enriched by reinforcing natural fiber. The reinforcement effect on natural fiber in their woven, braided, and knit forms enhances their structural properties. It improves the properties of natural fiber composites related to reinforcement with short and random-orientation fibers. The article also reviews the effect of the hybridization of natural fiber with cellulosic fiber, synthetic fiber, and intra-ply hybridization on its mechanical properties, dynamic mechanical properties, and free vibration characteristics, which are important for predicting the life and performance of natural fiber composites for weight-sensitive applications under dynamic load.

Composite sandwich structures are extensively used in aircraft applications. Aircraft components are required to be robust and lightweight. Sandwich structures made of carbon-fiber-reinforced polymer as the facing sheets and milled-glass-fiber-reinforced rigid polyurethane foam with a different glass fiber content as the core structure were prepared. The influence of glass fiber content in the foam on the sandwich structure’s mechanical properties was investigated. Flexural and compression tests were performed to assess the mechanical properties of the sandwich structures. Visual inspection and an optical microscope were used to observe the morphology of the polyurethane composite foams at different contents. From the flexural test, the force, facing stress and core shear stress improved with the increase in the milled fiber loading with the maximum increase at 10 wt.% loading and then a drop. Meanwhile, the compression modulus and strength increased up to 20 wt.% loadings and then dropped subsequently. The increase in the polyurethane composite foam’s compression strength shifted the bending load’s failure type from facing crack failure into core shear failure. The loadings range of 8–10 wt.% showed a transitional of the bending loading failure type. The density of the foams increased with the increase in milled glass fiber loading. At 10 wt.% loading, the density increased by 20%, and it increased by 47% at 30 wt.% loading. At 30 wt% loading, the optical microscope images of the foam showed wall thinning and broken walls that were responsible for the drop in the mechanical properties of the sandwich.