TESTING
expert steering system, suspension system and chassis, you cannot leverage the new autonomous driving technology. Take just the steering system as
an example. If the parts used aren’t bespoke to the vehicle and the conditions it will face, it will be severely limited in action, even with the most intelligent insight on far ahead objects. Thankfully, rigorous physical and environmental testing in the steering industry now means steering components can take on the debris, moisture and temperature variation that is faced in service, without resulting in water ingression or awkward high torque steering.
PHYSICAL TESTING Testing of steering systems is primarily about replicating as near to the same conditions that would be encountered on the road. Theoretical testing using calculations is a good start, but nothing gets closer to reality than physical testing. Using an on-site test facility with purpose-built test rigs, it is possible to test a subassembly of the entire steering system, presenting the whole structure with ‘like for like’ conditions that match the fi nal application. One of the most important
parameters to test for a military vehicle and its parts is the maximum load. With this information you can observe how much force a part can endure, in both tensile and compression, before a failure occurs. Using diff erent rigs to test a range of force applications, forces up to ±400kN can be applied both statically and dynamically.
Environmental test rig
Moreover, with enough data, you can compile a multitude of loads at their respective frequencies and cycles as part of a dynamic block testing programme. This programme eff ectively mirrors the real-life data that is gathered from the vehicle to accurately assess the true fatigue life of the part. With a variety of loads and
frequencies in place, engineers can measure the number of cycles that the parts can endure over time, performing 1,000,000 load cycles in only one week. That’s enough to replicate infi nite life for a part on a vehicle.
The US military is replacing one third of these HMMWVs
VALIDATING LIGHT- WEIGHTED PARTS Recently Pailton Engineering contributed to the development of a high-tech, well-armoured and incredibly agile military vehicle. The vehicle OEM asked for a small, lightweight steering drag link assembly that would allow the personnel carrier to remain light and nimble, but also have the strength to handle the maximum load values the vehicle may face out in service. Pailton’s team of designers analysed the loading information, selected the right joints by carrying out theoretical calculations on all aspects of the assembly. However, this standard way of working wasn’t suffi cient for such a non-standard request. As the customer wanted such a small,
light joint, just carrying out a theoretical calculation wasn’t enough. The team undertook a variety of physical testing to fi nd a small enough part to fi t the brief - which was incredibly challenging. They then took a diff erent path to get around this problem, keeping the same geometry of the drag link but changing the material to a lightweight, yet strong, alternative.
The company designed,
manufactured and continually tested this non-standard drag link throughout the design process to very accurate loads, to generate detailed fi ndings.
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