Experimental and numerical probabilistic multiscale investigation of short-fiber reinforced polymers
Topic(s) : Material and Structural Behavior - Simulation & Testing
Co-authors :
Benedikt ROHRMÜLLER (GERMANY), Jörg HOHE (GERMANY), Luise KÄRGER (GERMANY), Carla BECKMANNAbstract :
Short-fiber reinforced composites are used in lightweight construction due to their numerous advantages: they have a high strength-to-weight ratio together with a low specific density and can be manufactured cost efficiently in complex geometries. Standard manufacturing technologies like injection-molding can be used. In this contribution, the material uncertainty of a short-fiber reinforced composite material is investigated by mechanical characterization and multiscale simulations based thereon. The objective is to assess the propagation of uncertainties across the scales. Uncertainties in short-fiber reinforced composites can be caused by a scatter in the material properties but especially by a local variation in the fiber orientation and fiber density.
The material investigated has a heterogeneous microstructure consisting of a phenolic-resin polymer matrix reinforced with short glass fibers. The material compounding and manufacturing was done in a thermoset injection-molding process at Fraunhofer ICT [1]. Due to the material flow in the manufacturing process, this composite has an uncertainty in the fiber orientation distribution. This leads to an uncertainty in the mechanical properties. The material is characterized experimentally on plates manufactured under constant conditions to investigate the scatter of the material behavior. Additionally plates with different fiber volume contents are manufactured. The characterization of the uncertainty of the mechanical properties is done by experiments on different levels of structural hierarchy. Large scale tensile, compression and shear tests are performed on different plates to investigate the scatter between different plates. Small scale tensile tests are performed to investigate the scatter of the mechanical properties inside a plate. [2] Additionally microscale tensile tests are performed to investigate the debonding between fiber and matrix at the fiber-matrix interface. The experimental microstructure is rebuilt for numerical simulations. Finite element simulations of the microstructure are performed to investigate the influence of the scattering of the fiber orientation distribution and the fiber volume content. The microstructure simulations require different material models for fibers, matrix and the intermediate fiber-matrix interface. The fiber-matrix interface is modeled by a cohesive zone model. The microstructure simulations form the basis for multiscale simulations with a consideration of the uncertainty of the fiber orientation and fiber volume content.
Acknowledgement:
The present work has been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Grant no. 464119659. The financial support is gratefully acknowledged.
The material investigated has a heterogeneous microstructure consisting of a phenolic-resin polymer matrix reinforced with short glass fibers. The material compounding and manufacturing was done in a thermoset injection-molding process at Fraunhofer ICT [1]. Due to the material flow in the manufacturing process, this composite has an uncertainty in the fiber orientation distribution. This leads to an uncertainty in the mechanical properties. The material is characterized experimentally on plates manufactured under constant conditions to investigate the scatter of the material behavior. Additionally plates with different fiber volume contents are manufactured. The characterization of the uncertainty of the mechanical properties is done by experiments on different levels of structural hierarchy. Large scale tensile, compression and shear tests are performed on different plates to investigate the scatter between different plates. Small scale tensile tests are performed to investigate the scatter of the mechanical properties inside a plate. [2] Additionally microscale tensile tests are performed to investigate the debonding between fiber and matrix at the fiber-matrix interface. The experimental microstructure is rebuilt for numerical simulations. Finite element simulations of the microstructure are performed to investigate the influence of the scattering of the fiber orientation distribution and the fiber volume content. The microstructure simulations require different material models for fibers, matrix and the intermediate fiber-matrix interface. The fiber-matrix interface is modeled by a cohesive zone model. The microstructure simulations form the basis for multiscale simulations with a consideration of the uncertainty of the fiber orientation and fiber volume content.
Acknowledgement:
The present work has been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Grant no. 464119659. The financial support is gratefully acknowledged.