Buckling Analysis Of The Stiffened Shell For The Launch Vehicle

The stiffened shells are widely used in launch vehicles. The stability analysis of stiffened shells is studied theoretically and experimentally in this dissertation. An engineering-applicable formula for calculating the critical buckling load of stiffened shells is deduced with the theory of shallow shell. In the formula, our experience in structural strength design and the experimental results are considered. And such factors are also considered as differences in materials of the skin and the reinforcer, effects of bending, torsion, stretching and offcenter of the reinforcer. Furthermore, through post-buckling stress analysis of the skin, it is shown that even low stress level will result in buckling of the skin, but the skin still has loading capacity. The finite element method(FEM) is also employed in stability analysis of reinforced shells. In the FEM model the principle of equivalent width is employed to simplify calculation of the modulus of the skin and the loading capacity of the post-buckling skin is also considered. The geometric parameters of reinforcers are adjusted in order to accurately describe the deformation of the reinforced structure. Some conclusions and approaches that are practical in engineering design are obtained. A number of tests are carried out on different stiffened shells. The buckling behavior of the shells are illustrated with analysis. Comparisons between the experiment results and numerical results are made, which validate the theoretical analysis presented in this dissertation.