Research On Damage Characteristics Of Composite Stiffened Structure Under Low Velocity Impact

For decades, Composite structures have been widely used in the field of aerospace due to their high specific stiffness and strength, longer durability. However, composite structures usually have poor resistance to impact loading. Considering the time and cost of experiment, finite element methods offer the opportunity to develop a numerical model, which can accurately predict the damage. With the development of the computer, the finite element methods are convenient and efficient tools to use for the impact on composite structures.In this paper, an effective 3D finite element model of composite laminated plate, under low velocity impact, has been established for the analysis and prediction of damage behavior. By selecting fit material models, element model and contact, while the Chang-Chang failure criterion has been used to model intralaminar damage, the quadratic nominal stress criterion and the rule of B-K judgment were selected to model interlaminar damage as initial damage and damage extension. Further, the stiffened and strength degradation scheme were used to stimulate the progressive damage of composite structures. Compared with some damage parameter, it shows the method is reasonable and accurate.Through the validated finite element method, considering the influence of layup thickness, thickness of continuous layup, layer percent and interface angle. Rational laminated design suggestions are put forward.Then, the validated finite element method can also predict the damage of impact on composite stiffened plate. The involvement of the stiffened, the impact position and the spacing of stiffened are the possible influences to be considered.