Design and analysis of multi-section eccentric shaft

Abstract

In this report the preliminary design and analysis of multi-section eccentric shaft to be used on four-rotor Wankel rotary engine is discussed. Only a static analysis was performed due to time constraints. This novel design uses tapered three-sided polygon couplings to connect the different sections of the shaft. The design used Pro/ENGINEER® solid modeler. The shaft size was based on a maximum torque of 400 ft-lb. and a maximum angular velocity of 1,047 rad/sec (10,000 revolutions per minute, rpm). A finite element analysis was performed on the most highly loaded coupling of the shaft using COSMOS/M® finite element analysis system. Solid (brick) elements were used to model the two parts comprising the coupling. Contact (gap) elements were used to model the interface between the two parts of the coupling. The results of the static analysis show that the maximum von Mises stress in the parts is 58,000 psi. The factor of safety based on a minimum yield strength of 217,000 psi for a normalized and tempered 4340 low alloy steel forging is 3.74.