A unified modeling strategy of the stability and progressive damage behavior of CFRP double-blade composite stiffened structures (DCSS) under uniaxial compression

As a typical thin-walled structure, CFRP double-blade composite stiffened structure (DCSS) is widely used in the aerospace field and its stability and failure behavior demand a comprehensive understanding. In this work, a novel, unified modeling strategy is proposed for predicting the stability behavior and progressive damage processes of the DCSS under compression. A user-defined materials subroutine of the based-strain 3D-Hashin criterion and continuum damage mechanics model is developed using the FORTRAN language to simulate the intra-laminar damage initiation and propagation processes in the DCSS skin, stiffeners, and triangle zones. Moreover, the damage initiation and the extension of the inter-laminar in the skin and the skin-stiffener interface are revealed using the cohesive zone model. Furthermore, various experimental methods are employed to obtain the buckling, post-buckling and collapse behavior of the DCSS. The digital image correlation technique is used to describe the buckling and post-buckling displacement fields and the failure behavior of stiffened structures. Strain gauges are adopted to accurately acquire the buckling behavior of the DCSS. Finally, the buckling load, ultimate load, displacement data and failure modes of the stiffened structure obtained from the developed 3D finite element model are verified with the experimental results. The high correlation between the numerical and experimental results confirms the reliability of the proposed modeling strategy.

Automated summary

This paper proposes a novel and unified modeling strategy to predict the stability behavior and progressive damage processes of CFRP double-blade composite stiffened structure (DCSS) under compression. User-defined materials subroutine and continuum damage mechanics model are developed to simulate the intra-laminar and inter-laminar damage initiation and propagation processes. Experimental methods such as digital image correlation and strain gauges are employed to obtain the buckling, post-buckling, and failure behavior of the DCSS. The results from the developed 3D finite element model are verified with experimental results, showing a high correlation and confirming the reliability of the proposed modeling strategy.