INDIANAPOLIS—The use of simulation has made great strides the past few decades to where it is an integral part of the tire development process, but more work remains, according to the keynote speaker at the ACS Rubber Division Spring Technical Meeting in Indianapolis.
Ron Kennedy, managing director of the Center for Tire Research, said accuracy of the simulations currently limit their effectiveness in the process and is slowing their incorporation into the product approval process. Specifically, he said that simulations related to material response and properties are areas where improvements still need to be made.
CenTiRe is headquartered at Virginia Tech University and is a consortium between that school, the University of Akron and about 18 industry partners, including most of the leading tire makers. It conducts what Kennedy calls "pre-competitive research" in materials, tire physics, testing, manufacturing and sustainability that is directed by the industry members.
He told the Rubber Division audience that simulation fits in over all parts of tire development, including such areas as tire contact and stiffness prediction, state of cure prediction and forecasting cure temperature.
"It's a lot easier doing it on a computer than out in the factory with a thermocouple," said Kennedy, who worked 37 years in the tire industry—much of it in simulation—for Firestone, Bridgestone/Firestone and Hankook, before retiring and moving to CenTiRe.
Tire companies are doing a lot of work with tread wear simulation, and can predict hydroplaning behavior, showing how the tire loses contact and goes above the water. Similar models are used for icy road conditions, and can predict braking performance on ice.
But while scientists and engineers can predict some performance measurements, Kennedy said he is hearing that the tire companies and customers say the accuracy must improve. "They want a number. Trends are not enough," he said.
As automotive customers are starting to accept tire industry simulation projections rather than just test results, he said getting more accuracy currently is more important than developing new areas of use for simulation.
Simulation of rubber materials is one area with much room for improvement. There are many ways to get models of materials, so it is important to determine which are best for use in tire development projects. Kennedy added that material modeling must run quickly, so the other parts of development can go forward.
"For tire simulation accuracy, the materials need to be characterized in real tire operating conditions," he said.
The keynote speaker added that compound material characterization is needed beyond modulus and hysteresis, including such variables as more realistic and accurate friction representation.
Tire and material development currently are developed in separate parts within a tire company. He said one goal is the co-development of the two, with the elimination of silos in the research and development process. "Is there a way to take and build virtually to save on time and costs and tests?" Kennedy asked.
If this can be accomplished, he said it's likely results will improve, and tire companies can "get the best tire out the door."