Analysis of the nonlinear behavior of bio-based polymers reinforced with flax fibers
2012 (English)Conference paper, Poster (Refereed)
In last years competitive bio-based composite materials have been developed to reduce the dependence on non-renewable oil-based polymers and composites. This work is performed on composites with two bio-based matrix materials reinforced with flax fibers, Polylactic acid (PLA) and lignin. PLA is one of most commonly used bio-based thermoplastics, whereas lignin is relatively new material for composite applications.The stiffness of bast fibers (e.g. flax, hemp) in longitudinal direction is comparable to that of glass fibers (for example flax fibers have stiffness 50-100 GPa vs 72 GPa for E-glass fibers). The direct benefits of use of natural fibers in composites are light weight, reduced wear on the processing equipment and lower impact on the environment. However, their mechanical properties are subject to large variation and composites made of these fibers are sensitive to moisture and humidity. Study  has shown that in natural fiber composites the mechanical properties of fibers and the matrix are inherently nonlinear and the composite exhibits complex time dependent stress-strain behavior with loading rate effects and hysteresis loops. The phenomena dominating mechanical behavior may also include evolving microdamage (cracks, debonds etc) resulting in elastic properties degradation and development of irreversible strains. Therefore, material models of these materials should account for viscoelasticy and viscoplasticity accompanied with microdamage.In the present study systematic investigation of mechanical behaviour of flax fiber reinforced Lignin and PLA composites in tension is done. The objective is to indentify material model for these composites and to analyze the significance of viscoelastic, viscoplastic and stiffness reduction effects on mechanical behaviour.REFERENCES1. Sparnins E., Varna J., Joffe R., Nättinen K. and Lampinen J., “Time dependent behaviour of flax/starch composites,” Mechanics of Time-Dependent Materials, in press, 2006.
Place, publisher, year, edition, pages
Research subject Polymeric Composite Materials
IdentifiersURN: urn:nbn:se:ltu:diva-31812Local ID: 61b0b1c4-da8e-4ca6-a37b-945fd7b23f98OAI: oai:DiVA.org:ltu-31812DiVA: diva2:1005046
International Conference Mechanics of Composite Materials : 28/05/2012 - 01/06/2012
Godkänd; 2012; 20120918 (joffe)2016-09-302016-09-30Bibliographically approved