Dr. Maureira-Carsalade, Nelson

Cold-formed steel (CFS) members offer significant advantages over hot-rolled sections, primarily due to their high strength-to-weight ratio and versatility in forming various cross-sectional shapes. These attributes make CFS an efficient choice for design and construction. This paper reviews current design methods for CFS, focusing on the impact of initial imperfections. It also examines various techniques for measuring residual stress in CFS sections, including analytical, experimental, and numerical approaches. The study concludes that while analytical methods are effective, they become complex when accounting for material anisotropy. Laboratory techniques provide reliable measurements but are limited in detecting through-thickness residual stresses. Numerical approaches offer comprehensive insights but require further validation across different material and geometric configurations. The paper highlights the need for advanced analytical models, improved laboratory methods, and expanded numerical techniques to address existing knowledge gaps in residual stress assessment for CFS structures.

Natural fiber (NF) is one of the many resources that nature has provided. NFs decompose quickly and are biodegradable, renewable, and cost-effective. It may be scavenged from a variety of plant and animal sources. They are employed as reinforcing materials in polymers for NF composite development. Because of its environmental friendliness and long-term survivability, NF is growing in appeal among academics and researchers for usage in polymer composites. This study aims to offer a thorough evaluation of the most suitable and widely utilized natural fiber-reinforced polymer composites (NFPCs), along with their manufacture, processing, and applications. It also defines several external treatments of NF and their influence on the characteristics of NFPCs. The characteristics of NFPCs are affected by fiber supply, fiber type, and fiber structure. Numerous physical and chemical treatments were tested to see how they affected the thermal and strength properties of natural fiber-reinforced thermoplastic and thermosetting composites. Several polymer composite fabrication techniques were also studied. NFPCs have several disadvantages, notably low fire protection, poor strength properties, and greater moisture absorption, which have prevented their application. It is shown how NFPCs are employed in a variety of industries, particularly automotive and research industries. The review discovered that intentionally changing the regular fiber enhanced the thermochemical and physico-mechanical properties of the NFPCs by means of improving the grip between the fiber surface and the polymer framework. This study aims to provide important and fundamental facts on NF and their composites, which will aid in new investigations, the creation of a creative framework for polymer composite types, and the achievement of Sustainable Development Goals.