Optimization Design Of Reinforced Structural For Sheared Ringent Composite Laminate

Composite material has been widely used in aviation and aerospace structures because of its better specific strength and specific stiffness. Compared with metal material, it could reduce the structural weight. For various reasons, a series of holes were needed on composite structures. It would break the continuity of fibers while having holes on composite laminate. Thereby, the carrying capacity of the structure would be reduced. Meanwhile, there will be a concentrated stress around the opening. Hence, reinforced design for the opening was needed.In this paper, an initial optimization method for aircraft wing of openings with shear loads was studied. And a set of optimal design was summed. Study included as follows:(1) The determination of optimal design. After analysis the ringent composite laminate, it's found that buckling instability occurred in the laminate. Strain failures also happened around the opening. Using symmetrical intercalation reinforcement method around the opening, it's needed to optimal design the dimensions, thickness and the orientation of ply stacking.(2) Multidisciplinary integrated design. Using DOE of iSIGHT, 30 sample points were obtained with LHS (Latin hypercube sampling) method. Laminate of reinforced area were switched with equivalent model. Modeling 30 models by PCL(Patran Command Language). Optimum weight responses for each sample points were got by NASTRAN optimization function. By using iSIGHT again, establish approximations model of sample point with weight responses. Optimization the model we could obtain best geometry of reinforced sheet and weight response. Use the best geometry modeling, optimized, the corresponding thickness of equivalent model was obtained.(3) Model restore and error correction. Restore the laminate of the best reinforced area follow the basic rules of ply stacking as well as model features. Correct the error caused by equivalent model, carrying capacity of the reinforced composite laminate could return to that without opening.Using the optimization method above, structure achieved the desired results with a small weight increasing. Design problem was successfully solved. This optimization method could be used to solve other types of composite materials reinforced optimization problem, which has a certain universal significance.