Stability of advanced composite grid stiffened structures with delamination considering progressive failure and hygrothermal effects

The stability behavior of advanced grid stiffened structures (AGS) with delamination considering progressive failure and hygrothermal effects was investigated by numerical method. Based on the first order shear theory and the Von Karman non-linear assumption，the corresponding finite element formula was developed，and an appropriate progressive failure criterion was adopted. By some typical numerical examples，the effects of delamination，hygrothermal and the progressive failure on the stability behaviors of the AGS plate and shell are discussed. The numerical results indicate that the effects of delamination，hygrothermal and progressive failure on the stability of composite AGS structures can not be neglected when the above factors result in a jump of the buckling mode.