The structural efficiency parameters for the rotor system

supporting system and whole engine were put forward respectively according to the structure design requirements of the high bypass ratio turbofan engine

and the relations between the structural design parameters and the mechanics property parameters were established. The evaluation results for one typical engine exhibited that the average stress coefficients for the low pressure rotor of the high bypass ratio turbofan engine were between 0.2 and 0.3

lower than those of the other types of aero gas turbo engines because of the particularly large size of the fan. There were several unavoidable critical speeds with bending modes within the operation speed range

therefore the location of the joint structures of the rotor should be designed into the low stain energy zone. During maneuvering

the interval for the clearance between the stator and the rotor was ［-1.4

1.0］mm for the whole engine

and the low pressure turbine was the key position for the clearance control.