Need for cultural shift
South Carolina-based Clemson University’s Clemson Engineering Design Applications and Research (CEDAR) is a dedicated to research and development collaborating with the tyre industry to innovate and improve designs of automotive products, including tyres.
Heading the team is Dr Joshua D Summers, Professor of Mechanical Engineering, who is working with colleagues on issues related to functional, usable and environmental designs, with secondary emphasis on artistic design.
His areas of interest include collaborative design, knowledge management, and design enabler development with the overall objective of improving design through collaboration and computation. The work has resulted in well over 220 peer reviewed publications.
Sharing his thoughts on various tyre development research projects, he told Polymers & Tyre Asia in an interview that CEDAR Group is dedicated to work with the industry to help them innovate, improve their designs, and learn relevant approaches.
”We have extensive project experience in non-pneumatic tyre (NPT) development based on past work with NASA, Jet Propulsion Lab (JPL), Michelin, and the National Institute of Standards and Technology (NIST. His specific research interests are actually engineering design, where he uses projects to motivate and inform research, he said.
Commenting on recent developments in the design and production of NPT, Dr Summers acknowledged that there is a delay in NPT’s introduction to passenger vehicle market because it is an extremely critical product of safety.
“Introducing a revolutionary concept such as an NPT requires extensive testing and safety vetting. Moreover, there are governmental laws and regulations associated with tyres that create obstacles to commercial introduction,” he felt.
Many of these are focussed on regulations with respect to tyre inflation pressure. Without changes to these laws and regulations, the NPT would not qualify for integration into passenger vehicles. “I believe that is why Michelin has focussed first on introducing their Tweel NPT to the skid steer market first.”
Other issues might relate to high speed aspects such as acoustic and vibration issues, endurance issues etc. Materials and geometry are key to this. Next, consumer acceptance of this new paradigm is critical. Asking consumers to trust NPTs that do not look as “strong” or “solid” as regular pneumatic tyres is a big challenge.
“Finally, working with automotive companies to redesign their suspensions and other subsystems to capitalise on the potential benefits of NPTs is a cultural shift. This is going to take time to work with OEM’s and other suppliers to best integrate NPTs,” he said.
If NPT can offer lower rolling resistance, it will certainly be a major contribution to the environment because of lower carbon emission. But it will only really be realised with passenger tyre design. “Initial offerings of these NPTs might not achieve the full potential, because the NPT design is still only years old when compared to the century old tyre design,” Dr Summers said.
Explaining his work, the design professor said: “Our research was focused on developing the next generation NPT’s. This was inspired by the work on developing non-terrestrial tyres for lunar exploration. We worked with JPL and Michelin to develop many different meso-structures that could be made from metallic materials, but behave with the same shear deformation as polymers”
These meso-structures included honeycombs, auxetic honeycombs, chiral, cylindrical springs, helical coils, and others. Through physical prototyping and testing and extensive simulation, Dr Summers’ team was able to show that they can achieve performance that is comparable to the polyurethane based Tweel of Michelin but with the use of linear-elastic materials (avoiding issues of hysteretic loss).
Moreover, other aspects of low rolling resistance related to NPTs might include reduction in the tread size based on wear improvements from more uniform contact patches.