The growing ecological and environmental consciousness has driven efforts for development of new innovative materials for various end-use applications. Polymers synthesized from natural resources, have gained considerable research interest in the recent years. This review paper is intended to provide a brief outline of work that covers in the area of biocomposites, major class of biodegradable polymers, natural fibres, as well as their manufacturing techniques and properties has been highlighted. Various surface modification methods were incorporated to improve the fibre–matrix adhesion resulting in the enhancement of mechanical properties of the biocomposites. Moreover, an economical impact and future direction of these materials has been critically reviewed. This review concludes that the biocomposites form one of the emerging areas in polymer science that gain attention for use in various applications ranging from automobile to the building industries.

A review of the recent developments in biocomposites based on natural fibres and their application perspectives

It is widely known that the availability of lightweight structures with excellent energy absorption capacity is essential for numerous engineering applications. Inspired by many biological structures in nature, bio-inspired structures have been proved to exhibit a significant improvement over conventional structures in energy absorption capacity. Therefore, use of the biomimetic approach for designing novel lightweight structures with excellent energy absorption capacity has been increasing in engineering fields in recent years. This paper provides a comprehensive overview of recent advances in the development of bio-inspired structures for energy absorption applications. In particular, we describe the unique features and remarkable mechanical properties of biological structures such as plants and animals, which can be mimicked to design efficient energy absorbers. Next, we review and discuss the structural designs as well as the energy absorption characteristics of current bio-inspired structures with different configurations and structures, including multi-cell tubes, frusta, sandwich panels, composite plates, honeycombs, foams, building structures and lattices. These materials have been used for bio-inspired structures, including but not limited to metals, polymers, fibre-reinforced composites, concrete and glass. We also discussed the manufacturing techniques of bio-inspired structures based on conventional methods, and adaptive manufacturing (3D printing). Finally, contemporary challenges and future directions for bio-inspired structures are presented. This synopsis provides a useful platform for researchers and engineers to create novel designs of bio-inspired structures for energy absorption applications.

A review of recent research on bio-inspired structures and materials for energy absorption applications

The abundant availability and accessibility of plant fibres are the major reasons for an emerging new interest in sustainable technology. While focusing on the composite materials, the main points to be considered are environment friendliness and light weight, with high specific properties. This century has witnessed remarkable achievements in green technology in the field of materials science through the development of high-performance materials made from natural resources is increasing worldwide. Plant fibres are a kind of renewable resources, which have been renewed by nature and human ingenuity for thousands of years. The greatest challenge in working with plant fibre reinforced composites (PFRCs) is their large variation in properties and characteristics. A PFRCs properties are influenced by a number of variables, including the fibre type, environmental conditions, processing methods, and modification of the fibre. A detailed systematic review on these sustainable and renewable green materials is presented in this paper. The overall characteristics of plant fibres used in bio-composites, including source, type, structure, composition, as well as properties, will be reviewed. Finally, the review will conclude with recent developments and future trends of PFRCs as well as key issues that need to be addressed and resolved.

Plant fibre based bio-composites: Sustainable and renewable green materials

Environmentally-friendly monofilament cellulosic fibres have been widely used as alternatives for conventional steel reinforcement within concrete. Recently, the use of cellulosic fibre fabrics and their fabric reinforced polymer composites as reinforcement materials within and/or outside of construction materials (e.g. concrete) has gained popularity due to their inexpensive cost and favourable specific mechanical properties compared with synthetic fibre fabrics (e.g. E-glass). This review presents a summary of recent development on cellulosic fibre Fabric Reinforced Cementitious (FRC) and Fabric Reinforced Geopolymer (FRG) composites, as well as their cellulosic Fabric Reinforced Polymer (FRP) composites as reinforcements of concrete, masonry and timber structures for civil engineering applications. This review covers: (1) properties (i.e. chemical composition, microstructure, mechanical properties and cost) of monofilament cellulosic fibres and their comparison with synthetic fibres, the relationship between fibre chemical composition and fibre mechanical properties, parameters affect fibre properties; (2) properties (e.g. fabrication of monofilament fibres to fabrics and structures) of cellulosic fibre fabrics, properties of polymer matrices, and properties (i.e. flexural, tensile, impact, insulation and fire properties) of cellulosic fabric FRP composites; and (3) properties (compressive, flexural and tensile and impact properties) of cellulosic FRC and FRG composites, and the properties of cellulosic FRP composites reinforced concrete, masonry and timber structures. In addition, the degradation mechanisms of cellulosic FRC and FRP are discussed. Furthermore, the durability of FRC, FRG and FRP composites are reviewed and the methods to improve the durability of FRC, FRG and FRP composites from the aspects of fibre modification and matrix modification are reviewed and summarized.

A review of recent research on the use of cellulosic fibres, their fibre fabric reinforced cementitious, geo-polymer and polymer composites in civil engineering

There has been much effort to provide eco-friendly and biodegradable materials for the next generation of composite products owing to global environmental concerns and increased awareness of renewable green resources. An increase in the use of natural materials in composites has led to a reduction in greenhouse gas emissions and carbon footprint of composites. In addition to the benefits obtained from green materials, there are some challenges in working with them, such as poor compatibility between the reinforcing natural fiber and matrix and the relatively high moisture absorption of natural fibers. Green composites can be a suitable alternative for petroleum-based materials. However, before this can be accomplished, there are a number of issues that need to be addressed, including poor interfacial adhesion between the matrix and natural fibers, moisture absorption, poor fire resistance, low impact strength, and low durability. Several researchers have studied the properties of natural fiber composites. These investigations have resulted in the development of several procedures for modifying natural fibers and resins. To address the increasing demand to use eco-friendly materials in different applications, an up-do-date review on natural fiber and resin types and sources, modification and processing techniques, physical and mechanical behaviors, applications, life-cycle assessment, and other properties of green composites is required to provide a better understanding of the behavior of green composites. This paper presents such a review based on 322 studies published since 1978.

A review of natural fiber composites: properties, modification and processing techniques, characterization, applications

Despite the large number of recent reviews on green composites, limited investigation has taken place into the most appropriate applications for these materials. Green composites are regularly referred to as having potential uses in the automotive and construction sector, yet investigation of these applications reveals that they are often an inappropriate match for the unique material attributes of green composites. This review provides guidelines for engineers and designers on the appropriate application of green composites. A concise summary of the major material attributes of green composites is provided; accompanied by graphical comparisons of their relative properties. From these considerations, a series of complementary application properties are defined: these include applications that have a short life-span and involve limited exposure to moisture. The review concludes that green composites have potential for use in a number of applications, but as with all design, one must carefully match the material to the application.

Green composites: A review of material attributes and complementary applications

https://purehost.bath.ac.uk/ws/files/148864024/Effect_of_fibre_orientation_on_the_low_velocity_impact_response_of_thin_Dynemma_Composite_Laminates_accepted_manuscript_2017.pdf

Effect of fibre orientation on the low velocity impact response of thin Dyneema® composite laminates

A finite element methodology to predict the behaviour of Dyneema® HB26 fibre composites at quasi-static rates of deformation, under low velocity drop weight impact, and high velocity ballistic impact has been developed. A homogenised sub-laminate approach separated by cohesive tied contacts was employed. The modelling approach uses readily available material models within LS-DYNA, and is validated against experimental observations in literature. Plane-strain beam models provide accurate mechanisms of deformation, largely controlled through Mode II cohesive interface properties and kink band formation. Low velocity drop weight impact models of HB26 give force-deflection within 10% of new experimental observations, with in-plane shear strain contour plots from models directly compared with experimental Digital Image Correlation (DIC). Ballistic impact models utilising rate effects and damage showed similar modes of deformation and failure to that observed in literature, and provide a good approximation for ballistic limit under 600 m/s impact speed.

/pdf/finite-element-modelling-of-dyneema-composites-from-quasi-4mlb6rsnyt.pdf

Finite element modelling of Dyneema® composites: From quasi-static rates to ballistic impact

: This project provided fundamental understanding towards novel additive layer manufacturing approaches for highly-ordered, short-fiber architectures The fabrication challenge is a critical hurdle to the realization of complex, multi-scale architectures inspired by nature for improving the mechanical and functional properties of engineered materials The study was advanced on two fronts: (1) development of new hierarchical architecture based on ZnO nanorods grown on glass fibers and coated with tetraethyl orthosilicate (TEOS) to promote self-assembly; and (2) exploitation of ultrasonic manipulation for controlling orientation and distribution of reinforcing short fibers The ZnO/TEOS nanorods were shown to preserve mechanical properties of the base fibers while also displaying some healing capability for defects For the ultrasonic manipulation, both micro-scale and nano-scale reinforcements were studied using a new prototype assembly system developed for the project Enhancement of stiffness and strength properties in aligned directions was observed despite low volume fraction of reinforcement

/pdf/additive-layer-manufacturing-of-biologically-inspired-short-3lg4e2wbr5.pdf

Mark K. Hazzard

Papers

Green composites: A review of material attributes and complementary applications

Effect of fibre orientation on the low velocity impact response of thin Dyneema® composite laminates

Finite element modelling of Dyneema® composites: From quasi-static rates to ballistic impact

Additive Layer Manufacturing of Biologically Inspired Short Fibre Reinforced Composites

An investigation of in-plane performance of ultrahigh molecular weight polyethylene composites