For the case of coexistence of discrete and continuous variables in optimizing design of composite spindle

a hybrid algorithm consisting of genetic algorithm and enumeration algorithm was presented. From the prototype of an aero-engine low pressure turbine shaft

this hybrid algorithm was used to optimize ply angles and thickness of composite spindle for losing the weight of spindle under the premise of achieving the targets of static strength

critical speed and overall dimension. The results show that the hybrid algorithm can realize 5.54% and 3.87% extra weight loss for from 1 to 10 plies compared with full permutation algorithm and single genetic algorithm; and when plies numbers are greater than 6

the optimizing efficiency can be improved up to 3.1 times with using hybrid algorithm. Finally

the suggestion is given that the composite layer thickness is limited by strength and should not be too thin.