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The preliminary design of multistage axial compressor requires a vast number of design variables and limitations, the simultaneous investigation of which needs a complicated design program. This study provides a new algorithm by the use of combining multi-variable/multi-objective optimizations, meanline simulator and preliminary design program. On the one hand the two-layer optimization is used to consider all design variables and on the other the design limitations are put into the cost function together with surge margin and efficiency. The comparison of the results with the NASA transonic eight-stage compressor shows the ability of the new algorithm to achieve a compressor with better performance and lower weight.

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This paper describes a simple method for determined the critical buckling load of composite lattice conical structures under axially compressive load. To reveal the critical buckling strength of conical lattice structures, an analytical method based on the classical beam-column theory was applied. Characteristic equations were built according to the equilibrium equations. Furthermore, the buckling behavior of the conical composite shells under axial compression were investigated using experimental method. The specimens used in the experiment were made from glass/epoxy by winding the continuous glass fibers wetted with epoxy on a die with helical and circumferential grooves adopting a simplified manufacturing process. A relatively new flexible tool was developed for forming the grid-structures die, and the specimens were tested by using a universal testing machine. The diagrams of axial load versus displacement were recorded in real time during the tests. The experimental results describe failure modes that are present in the structures such as rib crippling, and general buckling. Axial buckling tests were carried out and the results were compared with the analytical method. The results have been summarized to verify the analytical method. Also, the proposed model has verified with the aid of finite element analysis. The proposed model suggests the possibility to improve the preliminary design solution with respect to the fully analytical approach.