Research On Buckling Behavior And Delamination Growth In Composite Laminates Containing Delamination

It is well known that composite laminates with delamination damage is common and can cause buckling and delaminnation growth under the load,then the compressive strength of laminates will drastically reduce.This limits the application of composite laminated structures in aeronautic critical structures.So the buckling behavior and delamination growth of composite laminates containing with delamination damage must be studied.At first, through the optimization of the composite laminates process, design the delamination orientation plate and close mold,the laminates containing delamination have been successfully prepared. Then the buckling behavior and delamination growth of composite laminates containing different type of delamination under axial compressive load has been investigated by experiment and numerical analysis,the relationship between buckling mode and delamination growth is discussed.Then the buckling behavior and delamination growth of composite laminates containing different type of delamination under axial compressive load has been investigated by experiment and numerical analysis. The result shows: Using the volume cell which has good interfacial ability and interfacial cell with non-thickness simulates the buckling behavior shows good agreement with the experiment. The buckling critical load of the specimen decline as the increasing of the delaminated area. The buckling mode of composite laminates with delamination is:at first the thinner laminate starts to buckle indicates the local buckling begin. When the thinner laminate reachs the maximum out-of-plane displacement, the thicker starts to buckle, it means the global bucking of the laminates begin. The delamination shape does not affect the buckling mode. There is only 5% in the buckling critical load of laminates with different shape but the same area delamination.The delamination growth of composite laminates containing different type of delamination under axial compressive load has been study: The delamination critical load of the specimen decline as the increasing of the delaminated area. The delaminated area and shape will not affect the delaminated direction and delaminated rate. The delaminated shape is similar with the initial delaminated shape. There is only 4% in the delamination critical load of laminates with different shape but the same area delaminationThere is important relationship between delamination growth and buckling mode: when the local buckling of the laminates begins, the delamination does not spread; the delamination growth begins before the global buckling behavior. The delamination spreads along perpendicular direction of load. When the delamination spreads to the edge of the laminates, the velocity of delamination growth speed up and the direction of delamination spread turn to the load direction, the laminates soon broken.The investigations in this paper will have important improvements for composites to be more widely used in aeronautic fields.