A viscoelastic-viscoplastic model for short-fibre reinforced polymers with complex fibre orientations

Abstract

Abstract. This paper presents an innovative approach for the modelling of viscous behaviour of short-fibre reinforced composites (SFRC) with complex distributions of fibre orientations and for a wide range of strain rates. As an alternative to more complex homogenisation methods, the model is based on an additive decomposition of the state potential for the computation of composite's macroscopic behaviour. Thus, the composite material is seen as the assembly of a matrix medium and several linear elastic fibre media. The division of short fibres into several families means that complex distributions of orientation or random orientation can be easily modelled. The matrix behaviour is strain-rate sensitive, i.e. viscoelastic and/or viscoplastic. Viscoelastic constitutive laws are based on a generalised linear Maxwell model and the modelling of the viscoplasticity is based on an overstress approach. The model is tested for the case of a polypropylene reinforced with short-glass fibres with distributed orientations and subjected to uniaxial tensile tests, in different loading directions and under different strain rates. Results demonstrate the efficiency of the model over a wide range of strain rates.

Effect of the Fiber Orientation of Glass Fiber Reinforced Polymer Composites on Mechanical Properties

“…Literature also shows that fiber orientation significantly affects the mechanical properties of the SFRP. If fibers are longitudinally oriented (parallel to the loading direction), mechanical properties are improved due to the efficient load transfer from matrix to fiber, whereas in the case of transversely oriented fibers (perpendicular to the loading direction), only a small or negligible increase in mechanical properties is observed compared to the non-reinforced (or neat) material [11,12]. Thus, the fiber orientation and distribution are parameters that are difficult to predetermine, yet it needs to be considered during product design and manufacturing.…”

The effect of short fiber orientation on long term shear behavior of 40% glass fiber reinforced polyphenylene sulfide

“…Literature also shows that fiber orientation significantly affects the mechanical properties of SFRP. If fibers are longitudinally oriented (parallel to the loading direction), mechanical properties are improved due to the efficient load transfer from matrix to fiber, whereas in case of transversely oriented fibers (perpendicular to the loading direction) only small or negligible increase in mechanical properties is observed compared to the non-reinforced (or neat) material [24][25]. Thus, it's important to consider the fiber orientation during product design and manufacturing.…”