ASSESSING THE STRUCTURAL RESPONSE OF AUTOMATED FIBRE PLACEMENT COMPOSITE STRUCTURES WITH GAPS AND OVERLAPS BY MEANS OF NUMERICAL APPROACHES

Kurzfassung

Ecomise is a European funded project enhancing process and evaluation techniques for automated dry fibre placement (AFP), infusion/ injection (RTI/ RTM) and curing for the purpose of achieving less energy and material consumption, higher reproducibility, reduction waste and rework. The paper focuses on the automated dry fibre placement technique (AFP), in particular on the assessment of manufacturing induced gaps and overlaps within the composite laminate. The goal is to determine the effect of these manufacturing deviations on the material behaviour in terms of stiffness and strength in order to enable a so called “as-built” analysis. Three different approaches are investigated, an analytical (comparable to a rule of mixtures) and two numerical based approaches (“virtual test” and multi-scale analysis), which are applied to two different types of deviations, long narrow gaps and long wide gaps/ overlaps. The investigation reveals that there is a considerable effect on stiffness and strength caused by the investigated deviations. It is further found that depending on the modelling approach and the applied failure criterion (e.g. first ply failure, progressive damage) the resulting stiffness and strength properties are quite diverse. This study is not exhaustive, further investigations and validation with experimental data is to be done.