Structural Analysis of Different Types of Chassis Designs for a Multi-Axle Heavy Commercial Vehicle

In recent years, the increasing capacity observed in air transportation requires enhanced security measures. The Aircraft Rescue and Fire Fighting (ARFF), which is one of the measures that are excessively taken in aviation, is constantly developing along with the sector, and it follows the technology closely, consequently increases its capacity day by day. In order to provide both civil and military air transportation safety, ARFF vehicles, which are specifically designed to operate in unusual boundary conditions with an ease. ARFF vehicles have high engine power in order to reach the crash site as soon as possible, aside from the high-power engine, they are equipped with all-wheel drive system (AWD) to increase mobility in rough terrain. Also, they are equipped with off road compatible tires, and it has high carrying capacity to carry extinguishing agents to be used to effectively respond to fire. In order for the vehicle to operate under these unusual boundary conditions, the frame component which works as carrier of the vehicle must be manufactured with materials which have high strength, and low weight and the frame should be as modular as possible. In this study, two different chassis designs were examined. The designs were created with the PTC Creo 3D modelling program for a multi-axle driven ARFF vehicle. Numerical calculations of the loads on the chassis were made with reference to the contact points of the chassis, rectangular-circular hollow section and different types of critical stress conditions. Finite element (FE) analysis for two different chassis conducted according to the calculation results. The main purpose of this study is to evaluate the stress conditions of different types of ladder chassis under static axle load according to two different critical loads and to determine the stresses acting on the chassis. As a result of the determination, engineering evaluations were made by evaluating the suitability of the chassis for production.