| Compression after impact of glass/epoxy laminates Adrian Gliszczyński1; 1LODZ UNIVERSITY OF TECHNOLOGY, Lodz, Poland; PAPER: 129/Modelling/Regular (Oral) SCHEDULED: 16:45/Wed. 30 Nov. 2022/Similan 1 ABSTRACT: Advanced fibrous composites are being used in many advanced structural applications, especially in aerospace. The problem which involving the use of reinforced plastic composite materials is the susceptibility to accidental low energy impact. In particular, such damage may be invisible causing a significantly lowering of the residual strength of composite component. Therefore this critical design aspect, implies application of conservative safety factors to the ultimate load values of composite components. In particular, in order to take into account low velocity impact damages and notch sensitivity effects the ultimate load value is generally reduced by 30%. Typical sources of low velocity impact are tool falling during manufacturing or maintenance operations, hail, debris on the track, bird collision, etc. The object of the analysis are composite plates made of GFRP laminate. The purpose of this work is to analyze the behavior of a composite plates taking into account barely visible impact damage generated by low velocity impact and the damage onset and evolution. The numerical calculations were conducted with the implementation of the progressive failure algorithm, based on the material property degradation method and implementation of the Hashin criterion as the damage initiation criterion. In all analyzed cases high consistency of numerical and experimental results was achieved. The occurrence of delamination, and their evolution was modeled in accordance with a bilinear traction-separation law. The obtained results were compared with the results of the experiment. Numerical calculations showed that delamination modeling enhances the compliance of experimental and numerical results (more than Progressive Failure algorithm application). Additionally, it was found out that the correct estimation of the areas and the nature of damages caused by the impact requires taking into account the In-Situ effect. Based on the results of experimental and numerical studies, it was stated that the highest compliance of determined material degradation was achieved by using the LaRC criterion. |
