Influence of debonding on nonlinear deflection responses of curved composite panel structure under hygro-thermo-mechanical loading-macro-mechanical FE approach

The excess geometrical deformation due to the in-plane hygrothermal and transverse mechanical loading are computationally (through a customized MATLAB code) obtained for the weakly bonded structure using the different kinematic theories in combination with the finite element steps. To evaluate the nonlinear deflection data a macro mechanical model is prepared mathematically considering the stretching effect (through the thickness), as well as the constant functions of displacement. The model includes the variation of composite properties due to the change in environmental temperature and moisture content including the necessary continuity assumptions between the separated layers for the weak bonding. The role of delamination i.e. location, position and size on the nonlinear deflection parameters are also computed under the combined loading (Hygral/Thermal/Mechanical/Hygro-Thermo-Mechanical). The solution accuracy and the elemental sensitivity have been computed for the proposed macro mechanical finite element model. Moreover, a set of numerical examples are solved to show the environmental effect on the flexural strength of a weakly bonded composite panel including the design-dependent parameters. The final results are indicating the necessity of the various kinematic model for the analysis of laminated structure with/without hygrothermal loading as well as the debonding.

Automated summary

This study computationally analyzed the excess geometrical deformation of weakly bonded structures due to in-plane hygrothermal and transverse mechanical loading using customized MATLAB code, as well as prepared a macro mechanical model to evaluate the nonlinear deflection data and assess the impact of composite properties variation and delamination on the deflection parameters under combined loading conditions. The necessity of various kinematic models for analyzing laminated structures with or without hygrothermal loading and debonding was demonstrated through numerical examples.