New hybrid method for composite grid structures analysis

A new hybrid method by conjunction of the smearing model with the stiffened model is formulated to analyze the composite advanced grid stiffened structures (AGS). The smearing model is homogenizing the stiffness of stiffeners based on the structural mechanics theory and the grid panel therefore can be equivalent to a plate. The stiffened element model is an exact method，which can provide the compatibility between stiffeners and plate. In addition，the numbers and orientation of the stiffeners of the element can be defined randomly by users. The numerical results indicate that the hybrid method is effective and accurate. It is also  known that the smearing model is remarkably affected by the distance and height of the ribs. The limitation of the hybrid method is investigated by simulating the grid-stiffened plate with a central circular cutout.