Lightweight Design of Automobile Drive Shaft Based on the Characteristics of Low Amplitude Load Strengthening

There are two kinds of internationally recognized approaches in terms of lightweight design. One is based on fatigue accumulated damage theory to achieve better reliability by optimal structural design; another is to use high performance lightweight materials. The former method takes very few considerations on the structural strengthening effects caused by the massive small loads in service. In order to ensure safety, the design is usually conservative, but the strength potential of the component is not fully exerted. In the latter method, cost is the biggest obstacle to lightweight materials in automotive applications. For the purpose of light weighting design on a fuel cell vehicle, the new design method is applied on drive shafts. The method is based on the low amplitude load strengthening characteristics of the material, and allows the stress, corresponding to test load, to enter into the strengthened range of the material. Under this condition, the light weighting design should assure that the reliability of the shaft is not impaired, even maximizes the strength potential of machine part in order to achieve the weight reduction and eventually to reduce the cost. At last, the feasibility of the design is verified by means of strength analysis and modal analysis based on the CAD model of light weighted shaft. The design applies to the load case of half shaft in independent axle, also provides technological reference for the structural lightweight design of vehicles and other machineries.