Application of air suspension system to improve the durability of chassis of multi-purpose forest fire fighting vehicle

In this study, the author replaced the leaf-spring suspension system with an air suspension system to reduce the chassis' dynamic load, evaluating the chassis' durability when using two suspension systems to complete the structure of the multi-purpose forest fire-fighting vehicle. The author uses Ansys software to build a finite element model of a multi-purpose forest fire-fighting vehicle chassis, evaluates its fatigue strength under dynamic loads from previous research, and proposes a structural improvement plan to extend its life chassis. The dynamic load acting on the chassis as an input parameter for the calculation is used from the research results. Fatigue test results utilizing Ansys software with dynamic load computed in moving conditions on ISO roads class E and F with leaf-spring and air suspension systems demonstrate that the original chassis is not robust. After enhancing the chassis structure, the texturing region around the fatigue point has increased (raising the corner radius). As a result, the chassis weight increased by 35.15 kg and the minimum fatigue cycle was larger than 10⁶ cycles while employing the air suspension system. The durability study suggested increasing the corner radius at the fatigue point to strengthen the chassis structure. The stress concentration radius is gradually increased from 5 to 10 mm to enhance material thickness and chassis fatigue cycles. These findings can be used to provide a scientific method for calculating and assessing the durability of car chassis and shell details, helping Vietnam's auto sector grow.