3D microstructure modeling of long fiber reinforced thermoplastics

A novel procedure for the generation of a representative volume element for long fiber reinforced thermoplastics and materials with a similar microstructure is presented here. It is characterized by a maximum fiber aspect ratio of approx. 5000 and a maximum fiber volume fraction up to 25%. The modeling procedure is based on characteristic values describing the microstructure in a statistical sense, which are the fiber orientation distribution, the fiber length distribution and the fiber volume content. The resulting mesh for finite element analysis represents the microstructure with a relatively low element count, modeling each fiber only by a single element per cross section. Hence, the model is computationally very efficient and allows the analysis of comparably large structures which include the complete fiber length spectrum of the investigated material. The procedure is validated against the elastic properties of three material variants with different fiber volume fractions, incorporating their experimental measured fiber orientation and length distributions.