The airbag support arm is the core support part of the vehicle wheel drive axle, as shown in Figure 1. It is connected with the vehicle box, shock absorber airbag module and drive system. It can carry the rear load of the vehicle, support the drive axle and cushion the shock absorber airbag. Under the driving state of the vehicle, it bears variable impact shock absorption load, and its main failure mode is fatigue failure.

Automobile airbag support arm was originally mainly produced by nodular cast iron. In order to realize automobile lightweight, it is developed from iron castings and steel castings to aluminum alloy forgings to realize the lightweight of airbag support arm products. Aluminum alloy airbag support arm is used for a new energy vehicle. The material is a35.2 alloy. Mechanical property requirements: body sampling tensile strength > 300mpa, yield strength > 210mpa, elongation > 8%.

The product broke in the bench test at the initial stage of development, and then the product structure was improved, as shown in Figure 2. ① Move the product boundary at 5mm to the left in the direction indicated by the arrow; ② Cancel the transition arc to form a straight line, and raise the bolt mounting hole surface by 5mm. The overall stiffness of the improved parts is strengthened and the stress condition is more reasonable. The mechanical property test results of the product body are sampled. After the multi wheel bench test, the product performance fully meets the design requirements. The bench test of the product is shown in Figure 3.