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Dr. Pingsha Dong |
TIME magazine has recognized ME graduate Dr. Pingsha Dong for his groundbreaking work in determining metal fatigue in a special Sept. 12 section on math innovators. The system he developed, Verity™, is, as the TIME writer stated, “revolutionizing the field.”
Dr. Dong is the Technical Director at the Center for Welded Structures Research at Battelle in Columbus, Ohio. It was there that he developed Verity™, which predicts the fatigue life of welded structures with unprecedented accuracy.
“The Verity™ process offers a unique and yet simple stress calculation method at geometric discontinuities (notches or corners) in engineering structures, which offers mesh-size insensitivity of computer models and has been widely used for strength, fracture, and fatigue evaluation,” said Dr. Dong. “The method solves the most challenging problem in fatigue design and life predictions of welded structures, which have faced engineers for many decades.”
Discovering the key to developing a successful process did not come quickly. Dr. Dong led a group of some 8 PhD-level research scientists for more than 10 years. The potential applications promise to have an enormous effect on the automotive industry, among others.
In an article in Automotive Design and Production by Kermit Whitfield, Dr. Dong noted that Verity™ is “not just an incremental improvement. This method can cut development cost and time by more than half.”
The key to Verity™ is a novel use of nodal forces to calculate stress concentration at geometric discontinuities rather than using stress output from typical finite element solutions embodied by various commercial finite element packages such as ABAQUS, NATRAN, etc. When dealing with notches or sharp corners, stresses are sensitiveity (e.g., rapidly increasing without a bound as the element size is reduced) to element sizes and element types used in a finite element model. With VerityTM, the the stresses calculated with Verity™ method is insensitive to element size used, eliminating the arbitrariness in stress concentration determination with conventional methods, since nodal forces from a finite element solution have to satisfy equilibrium conditions while stresses don’t.
Today, the six sigma philosophy has been adopted by major industries worldwide, particularly in the automotive industry, to gain the competitative edge in reducing process variability, improve product quality and reliability. VerityTM method has started to play a major role in eliminating CAE calculation-related variability in stress calculations for strength and fatigue/durability design and optimization.
Verity™ also has applications in reducing weight. In the past, conventional fatigue design of welded structures is purely experience-based and over-design is the norm due to uncertainties (e.g., mesh sensitivity) in stress calculations. Because Verity™ provides accurate (i.e., mesh-insensitive) stress determination , weld joints can be designed to meet the necessary fatigue specifications. This can potentially result in a savings of a much needed weight savings in automotive structures without scarifying safety and reliability.
Dr. Dong, who earned his masters in Mechanical Engineering in 1984 and his doctorate in 1989 at the University of Michigan, credited ME with providing the foundation for his latest achievement.
“My PhD advisor was Professor Jwo Pan,” said Dr. Dong, “who has had a great deal of lasting influence on my research skill development, for which I’m very grateful to this day. There were numerous other faculty members at the-then MEAM Department, like Professor Elijah Kannatey-Asibu, Jr. and [Emeritus] Professor Maria Cominou, whose scholarship, renowned academic reputations, and dedication to teaching cannot be overemphasized in making a positive impact on many of us in our later professional career pursuit. I would also like to acknowledge Professor Noboru Kikuchi, whose dedication to computational research and enthusiasm were contagious to many of us.
“I have also collaborated with Professor Jack Hu of ME on a major National Institute of Standards and Technology Advanced Technology Program on Intelligent Resistance Welding (IRW) participated by over a dozen automotive companies including Big 3. I’ve very much enjoyed Prof. Hu’s insight into some of the major manufacturing challenges faced by the automotive industry. Knolwedge gained from programs like that and many others over the years contributed in one way or other to the Verity™ development.”
Dr. Dong’s achievements would have been an impossible dream when he was growing up in Dalian, a major seaside city in northeast China. The culture revolution had started when he was at about the third grade. From then on, the school no longer followed the regular curriculum.
“Most of the day-to-day activities at school were focused upon supporting various political events and related readings,” said Dr. Dong. “When I graduated from high school in 1973, all of the universities had been closed down for a number of years. Instead, the government asked all high school graduates to go to the remote countryside to receive so-called ‘re-education’ from peasants. When in coutryside, it was strictly forbidden to study any pre-culture revolution test books, while receiving ‘re-education.’
“The government asked all young people to swear that we planned to stay in the countryside forever to serve the country and the Party. Although it seemed very unlikely at that time, for the very limited few of us who still were still dreaming about to be able to go to college one day, we had to try every possible way to make up what we did not learn in school under the worst possible conditions and political environment. I had saved some math and physics books that my father gave me, and I was able to read them at night by a kerosene lantern.”
Fortunately, Dr. Dong was among the first major group of Chinese students on government scholarship to pursue PhDs in western countries. “There were about 350 of us students, and we had little knowledge about U.S. universities,” he said. “Some of us recognized the University of Michigan because the U.S. Ambassador to China was Professor Leonard Woodcock, who was with the university’s Political Science department. That’s why Michigan was better known then in China and recognized as one of the best engineering schools in the U.S.”
Dr. Dong’s research interests and activities cover advanced computational simulation methods for thermal manufacturing processes (including various thermal-based materials processing, thermal cutting, welding/joining, solid state bonding/joining) and advanced design/analysis techniques for fabricated structures. He joined Battelle in 1994.
In addition to his recognition by TIME, some of the major awards he has received are the Laurels 2004 Award from Aviation Week & Space Technology, the 2004 American Welding Society R. D. Thomas Memorial Award,and the SAE International Henry Ford II Distinguished Award for Excellence in Automotive Engineering in 2003. He also received the 2003 Ford Motor Company Outstanding Contribution Award for Vehicle Engineering and Validation for implementing Verity™ at Ford. .
Beyond the publicity generated by the TIME article, there’s still the matter how well the application works. The prospects for Verity™ are significant. It has already been adopted by Ford Motor Company and is part of the company’s durability simulation software. Other companies have joined Battelle’s “Joint Industry Project” to look for further applications. As Dr. Dong said, “I don’t think there is any other choice in terms of weld fatigue prediction. Everyone will go to this, if he or she is serious about weld fatigue design.”
Looking back at his journey from the re-education camp in the Chinese countryside to the pages of TIME magazine, Dr. Dong said, “If anything can be said about such an experience in terms of the impact on a person’s later career, it strengthens your determination. It changes your outlook on life. In my case, it taught me perseverance is essential for every success.”