New smeared stiffener theory for grid-stiffened composite panels

An improved basic mechanical hypothesis was proposed to account for the mechanical behavior of grid stiffened composite panels. With such hypothesis, a new smeared stiffener approach was developed to effectively take into consideration the stiffener-skin interaction effects. The parameterized representation of grid unit cell was described, and the corresponding mechanical model was established. Such generalized model can be used for global buckling analysis of grid-stiffened structures with different types of grid layouts. Therefore, it is very useful for aerospace structural design. Using Rayleigh-Ritz method combined with the developed smeared stiffener approach, the eigen function for the global buckling load of grid stiffened panels was derived. Finally, various test examples with different grid patterns were analyzed and the results were compared with those obtained with existing methods. It is shown that the developed approach has better accuracy and thus can be used for optimal design of grid stiffened composite structures.