Finite element analysis of buckling and salvage of a composite cylindrical shell with an open hole

Study on the salvage of an axial penetrating crack on the composite cylindrical shell with a reinforced open hole is carried out. An FEM model is established for the original structure with defects to analyze its compressive buckling strength and modes. The relationship of the penetrating crack length with the buckling strength of the cracked cylindrical shell is obtained. Comparison of the buckling strength is performed with that of the composite cylindrical shell without crack. The results show that, the buckling strength of the cylindrical shell with crack becomes lower than that of the cylindrical shell without crack. The longer the crack is, the lower the buckling strength is. With the penetrating crack under 200mm, the effect on the load-bearing capacity of the structure is tiny. While the crack continues to grow, the buckling area moves from the area above the open to where the crack lies, and this results in a sharp drop of the buckling strength. In this case, proper repair should be taken to salvage the structure. The results show that, to the cylindrical shell, the shear carrying capacity of the area where the crack lies is enhanced. After proper repair, the buckling mode returns to that of the cylindrical shell without any crack with a little increase in buckling strength. This illustrates the effectiveness of the improved salvage method.