The high demand for plastic and polymeric materials which keeps rising every year makes them important industries, for which sustainability is a crucial aspect to be taken into account. Therefore, it becomes a requirement to makes it a clean and eco-friendly industry. Cellulose creates an excellent opportunity to minimize the effect of non-degradable materials by using it as a filler for either a synthesis matrix or a natural starch matrix. It is the primary substance in the walls of plant cells, helping plants to remain stiff and upright, and can be found in plant sources, agriculture waste, animals, and bacterial pellicle. In this review, we discussed the recent research development and studies in the field of biocomposites that focused on the techniques of extracting micro- and nanocellulose, treatment and modification of cellulose, classification, and applications of cellulose. In addition, this review paper looked inward on how the reinforcement of micro- and nanocellulose can yield a material with improved performance. This article featured the performances, limitations, and possible areas of improvement to fit into the broader range of engineering applications.

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The single-layer and multi-layer finite element models are developed and examined for adequacy in predicting the elastic-damage response of fiber-reinforced polymer composite laminates. A new experimental-computational approach featuring a two-tier mesh convergence analysis of the finite element models is developed. A 12-ply carbon fiber-reinforced polymer composite laminate beam specimen with anti-symmetric layups is designed and loaded to induce matrix damage under significant deflection without catastrophic fracture. A constitutive model incorporating Hashin’s equations for damage initiation criteria, along with an energy-based damage propagation law is employed in the finite element simulation. The results shows that the multi-layer finite element model predicts well the load–deflection curve of the carbon fiber-reinforced polymer composite laminate, while the single-layer model overestimates the elastic flexural stiffness of the specimen by 47 %. During the flexural deformation, matrix damage initiates in the central and edge regions of the critical laminas under compressive and tensile stresses, respectively. The multi-layer finite element model also predicted the matrix-induced interface delamination along the edges of the critical laminas under tension, as observed experimentally. The model demonstrates the adequacy in representing the role of lamina interface in dictating the elastic-damage response of carbon fiber-reinforced polymer composite laminates manufactured by prepreg layups method.

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Composite structures are made of multidirectional (MD) fiber-reinforced polymer (FRP) composite laminates, which fail due to multiple damages in matrix, interface, and fiber constituents at different scales. The yield point of a unidirectional FRP composite is assumed as the lamina strength limit representing the damage initiation phenomena, while yielding of MD composites in structural applications are not quantified due to the complexity of the sequence of damage evolutions in different laminas dependent on their angle and specification. This paper proposes a new method to identify the yield point of MD composite structures based on the evolution of the damage dissipation energy (DDE). Such a characteristic evolution curve is computed using a validated finite element model with a mesoscale damage-based constitutive model that accounts for different matrix and fiber failure modes in angle lamina. The yield point of composite structures is identified to correspond to a 5% increase in the initial slope of the DDE evolution curve. The yield points of three antisymmetric MD FRP composite structures under flexural loading conditions are established based on Hashin unidirectional (UD) criteria and the energy-based criterion. It is shown that the new energy concept provides a significantly larger safe limit of yield for MD composite structures compared to UD criteria, in which the accumulation of energy dissipated due to all damage modes is less than 5% of the fracture energy required for the structural rupture.