Influence of matrix properties on fatigue behavior of fiber reinforced polymers

• Applicant: Professor Dr.-Ing. Joachim Hausmann
• Subject Area: Polymeric and Biogenic Materials and Derived Composites
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 468045930

Fiber reinforced composite materials with thermoplastic matrix are used increasingly in many transport applications. Thermoplastic matrix materials offer higher ductility and toughness compared to common thermoset systems. These superior properties lead to the question of the influence of the composite constituents on the fatigue properties of a laminate. The matrix properties are influencing the load cycles until failure as well as the deformation behavior at a certain life time. Established thermoset matrix material reveal on laminate or lamina level experimentally parameterized failure models. An associated damage model reveals the cycles until failure and the deformation behavior over the life time. Anisotropy along with microscopic inhomogeneity due to fiber and matrix lead to strong dependency of the fatigue behavior of continuous fiber reinforced polymers to mean stress and load direction. By this scheme experimentally determined description reveals the global response of the material system on external loads and their direction and sequence. Problem is that the precision of prediction is determined by experimental effort and each change of constituent properties requires new experimental characterization. The behavior of matrix, fibers and fiber-matrix interface on microscopic level is responsible for the global response of the composite material. New fiber-matrix combinations and thus new properties regarding fatigue behavior require profound understanding of the influence of the constituents. Aim of the project is therefore generation of basic and systematic understanding and description of the interaction of mechanical matrix properties and the fatigue behavior of fiber-polymer composites on microscopic level. By irradiation induced crosslinking the properties of the matrix material are modified systematically and their influence on the fatigue properties of the composite material is investigated experimentally and with the aid of models. Exemplary material systems will be used which allow separation of influencing factors.

• DFG Programme: Research Grants