A partner for better, safer communication products

cellphones spelling out U-T-A
Nokia officials say the cellphone company's partnership with UT Arlington has resulted in technical advances in several significant research areas.

Cellphones. They used to be a novelty. Now it seems everybody has one.

In 1992, less than 1 percent of people worldwide owned cellphones. Just 10 years later, 18 percent (1.14 billion people) had them—more than the number with conventional phone lines. Today, more than 182 million Americans are wireless subscribers, a penetration rate of more than 60 percent.

The research group INFORM estimates that by the end of 2005 consumers will have stockpiled 500 million used cellphones, many of which may end up in landfills, leaching tons of toxic metals like lead and nickel into the environment.

University-corporate partnerships like The University of Texas at Arlington’s relationship with Nokia may offer a solution. The Finnish cellphone manufacturer is funding an assortment of projects to keep its products dependable, cost-efficient and environmentally friendly.

One problem cellphone designers face is the lead-based solder in the phones’ electronic connections. Mechanical and aerospace engineering Professor Dereje Agonafer and materials science and engineering Professor Choong-Un Kim are working on Nokia-sponsored research to develop replacements for current solders.

Dr. Kim is investigating the influence of minor constituents on the properties important in determining the reliability of lead-free solder joints. He is producing a database that displays changes to the structure, mechanical strength and toughness induced by minor amounts of additional elements.

Dr. Agonafer is investigating methods to experimentally calculate the characteristic life of the lead-free solder joints. He’s running different accelerated tests and developing a failure-life prediction model and finite element simulations based on the results of those experiments.

“We have an extraordinarily good and mutually beneficial relationship with Nokia,” Agonafer said. “Not only has Nokia sponsored research that helps us keep up to date on industry advances, they have also given us equipment valued at tens of thousands of dollars, cash gifts to sponsor two senior design projects and supported general research in electronic packaging for telecommunications products. I couldn’t ask for a more vibrant, enthusiastic partner.”

Viswam Puligandla, Nokia principal scientist and a UT Arlington adjunct professor, says the relationship has grown steadily in recent years and encompasses projects in materials science, hardware simulation and other areas.

“The cooperative activities between the two institutions have been positive and resulted in several technical contributions in the areas of research,” he said.

In the College of Science, mathematics Associate Professor Jianzhong Su and Assistant Professor Hua Shan have studied the distribution of forces on a dropped phone as it hits the floor. Their results? Not what they expected.   

The second impact after the bounce caused more damage than the first. Dropping the phone at an almost flat angle created twice the force of impact as a steep angle. The shape and weight distribution of a phone correlated directly to the points and forces of impact.

Nokia previously tested its phones in a tumbling machine where sensors measured the impact as the phone struck various surfaces. Then Su and Shan developed precise numeric simulations. A commercial software program took three days to compute the effect of one 12-millisecond impact; Su and Shan’s virtual tumbling machine does it in two minutes.

Is solving such problems for Nokia good science?

“Absolutely,” Dr. Su says. “We need to pursue realistic problems, and the graduate students who work with us need to be able to solve these real-world problems, too.” Su and Shan hope to foster long-term research partnerships with Nokia to develop their industrial mathematics program.

Product reliability is a major factor in customer satisfaction, and mechanical and aerospace engineering Professor Bo Wang and his associates, Assistant Professor Brian Dennis and postdoctoral researcher Shen-Zue Han, have received Nokia funding for three years to research the thermal and impact performance of electronic packages—the guts of a cellphone. The team developed a novel testing approach—simulation-based design optimization—that utilized an approximate model.

Nokia was so satisfied with the simulation-based method that many units within the company now use it. Meanwhile, the researchers have shifted to simulations of miniature fuel cells, which Nokia wants to power a variety of mobile communications products. These cells offer a longer operating life and are quicker and easier to recharge.

— Roger Tuttle