Numerical and experimental studies of the influence of curing and residual stresses on buckling in thin-walled, CFRP square-section profiles

The study provides the first comprehensive experimental and numerical study of thin-walled, carbon fibre square-section columns subjected to static compression. The profiles were manufactured from unidirectional prepreg tape of Hexcel AS4 high-strength carbon fibres in HexPly (R) 8552 thermoset resin with ply angles [45/-45/45/-45](s). The dimensions of the columns were: (height x width x length) 80 mm x 80 mm x 240 mm and the wall thickness was 0.92 mm. Advanced Finite Element Models (FEM) of the residual stresses generated during production were used as a basis for simulations of static compression. The deformation predicted by these models showed excellent agreement with 3D scans of the columns. These results also highlighted the residual stress concentrations generated at sample corners during production. It was found that the residual stresses from the autoclaving process significantly enhance the buckling load performance (by similar to 35%) and that the models provide an effective comparison with the experimental results (<10% error). This demonstrates the importance including residual stresses in FEM of buckling, but also highlights residual stress tailoring as a route to significantly enhance the buckling load capacity of carbon fibre systems used in industrial applications.

Automated summary

The study provides a comprehensive investigation of thin-walled, carbon fibre square-section columns under static compression, highlighting the significant enhancement of buckling load performance by residual stresses. The models show good agreement with experimental results.