Influence of geometric parameters on the knockdown factor of the buckling of stiffened cylindrical shells under axial compression
Stiffened cylindrical shells are widely used in the space vehicle structures.Due to the manufacturing process,the actual products always have unavoidable geometric imperfections,the axial compression capacity of the real structure is far lower than the theoretical buckling load,and it is necessary to introduce a knockdown factor(0-1)to correct to make the theoretical solution as close as possible to the experimental value while ensuring safety.When the structural geometric parameters are adjusted during the design iteration,the knockdown factor may be changed too.It is helpful to get the appropriate knockdown factor conveniently and accurately to clarify the change law about knockdown factor,that can ensure the structural safety,reduce the weight and shorten the design cycle.The paper introduces the implementation process of Single Boundary Perturbation Approach,and investigates the convergence of the main analysis parameters,and clarify their selection principles.Based on this method,the knockdown factor change rule is studied when parameters change.The results show that the knockdown factor increases linearly with the increase of skin thickness and decreases linearly with the increase of stringer area of section which mean the larger skin thickness and the lower and thinner stringer will reduce the structural imperfection sensitivity,and the structural height has no significant effect on the knockdown factor.
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