On an Accelerated Fatigue Track, we simulate the accumulation of kilometres equivalent to the entire service life of the vehicle as far as structural components are concerned as well as elements of the bus. The tests combine the running on various surfaces at different speeds and a series of manoeuvres to stress the structure of the vehicle.
The buses are also subjected to loading conditions that simulate actual usage; often the most critical load condition to test the durability of the entire vehicle under the most severe conditions.
A wide variety of surfaces and elements are used during testing which simulates the behaviour of the unit during its life in an accelerated and amplified manner.
Cobblestones, for example, cause a high frequency of large vertical forces that affect the vehicle’s suspension systems and structure. One of the most demanding stretches is the waterway with different size boreholes that cause a series of strong impacts that are transmitted to the structure in the form of high longitudinal and vertical loads.
Other areas of the circuit, such as the flat pavement with bumps, enable the driver to detect internal noise in the passenger compartment of the bus and evaluate the comfort of both driver and passengers.
The undulations of the track (symmetrical and asymmetrical on the left and right wheels) test the suspension systems and help in assessing the level of comfort inside the vehicle.
Areas of gravel make it possible to see the intrusion of dust into the various compartments as well as projecting gravel, dirt and dust onto the underside of the bus causing wear and corrosion.
These tests consist of the accumulation of test kilometres and the completion of figure 8 manoeuvres, following guidelines established by IDIADA on the accelerated fatigue track.
These tests are complemented by ramp starts. The buses undergo stop, door open / close manoeuvres and wheelchair ramp unfolding / folding on a 15% ramp.
The test results and the daily inspection of the buses are used to analyse the behaviour and indicate any details that can be improved.
The testing is ultimately intended to simulate the vehicle's entire useful life, ensuring good durability in the harshest conditions. That is why, at this stage of testing, it is so important to detect incidents from the moment they appear and to properly implement corrective measures.
