Mechanics of Multi-functional Biocomposites

University Of Massachusetts, Dartmouth, North Dartmouth MA

Investigators

Abstract

The objective of this award is to fabricate natural fiber composites that are highly durable and multi-functional. Fiber-reinforced polymer composites are made by combining a polymer together with strong reinforcing fibers. Both glass and carbon fibers are relatively expensive, man-made fibers. However natural fibers are abundant, recyclable and cheap. There is a growing trend to use natural fiber reinforced composites in several commercial applications such as automobiles, building construction, sporting goods, and electronic goods. Although natural fiber composites are already used in several industrial applications, their use in load bearing applications is very limited due to their poor durability and mechanical properties such as stiffness, strength, crack initiation and propagation resistance. Multi-functional properties such as stiffness, strength and crack resistance, and damage sensing will be achieved by coating natural fibers with graphene and embedding short carbon fibers between the laminates. In addition, research will be performed to understand the damage evolution of the natural composites under various mechanical loads using the three-dimensional electrical conductive network generated by the embedded graphene and short carbon fiber elements. This project will provide training opportunities to graduate and undergraduate students on embedding graphene into natural fibers, fabrication of composites, and multi-scale electro-mechanical characterization. The research activities will also promote the recruitment and mentoring of underrepresented students in cutting-edge scientific techniques through outreach in local public high schools. A comprehensive experimental study will be conducted to investigate damage evolution at different length scales in multi-functional natural fiber reinforced composites. To accomplish this objective, novel and challenging experiments incorporating the electro-mechanical response of three dimensional electrical conductive networks will be performed under quasi-static mechanical loading conditions. Highly sensitive conductive networks will be generated by embedding graphene in natural fibers laminates along in-plane directions, and by flocking short carbon fibers along the thickness direction between the laminates. It is hypothesized that the generated conductive network will undergo changes during mechanical loads to reflect damage mechanisms such as fiber pulling from the laminates, matrix cracking, delamination between laminates, and crack bridging. In addition to macro-scale experiments, nano-scale experiments will also be performed using a micro-tensile tester embedded, conductive mode atomic force microscope to capture change in current profile under tensile and shearing loading conditions.