蜂窝夹芯挖补修理结构弯曲性能研究

The flexural behavior of scarf repaired honeycomb sandwich structures was investigated via experiments and finite element analysis. A three-point bending test was carried out on both undamaged and repaired specimens. Test results demonstrate that the failure mode is core shearing, and that the flexural strength recovery ratio of the repaired to the undamaged panels is 110%. The flexural rigidity of the repaired panel is slightly higher than that of the undamaged panel. Based on these results, a 3D finite element model was proposed to investigate the flexural behavior of the repaired specimens. Using VUSDFLD, we developed Hashin fabric and Besant failure criteria to achieve the damage initiation and evolution of composite and honeycomb materials. The failure pattern, the ultimate load and the calculated stiffness are in good agreement with the test results. Then the effect of the damage diameter and the thickness of the patch on the repaired panels was analyzed by changing the parameters of the FEM, and the results show that with the increase of the damage diameter from 30 mm to 70 mm, the ultimate loads of repaired specimens increase, then decrease, and finally reach the maximal value at the diameter of 50 mm; besides, the strength recovery ratio is larger than 100% while the thickness of the patch ranges from 1 mm to 2.5 mm. This study indicates that the numerical model developed provides an efficient method for repair design of composite honeycomb sandwich panels.