Simon Ramo Founders Award

1998 Founders Award Acceptance Remarks

Yuan-Cheng B. FungRemarks made by Yuan-Cheng B. Fung on October 4, 1998 at the National Academy of Engineering 1998 annual meeting, Washington, D.C.

1998 Founders Award citation for Yuan-Cheng B. Fung

President Wulf, Dr. Brenner, Fellow Members of the Academy, Colleagues, Friends, Ladies and Gentlemen:

I deeply appreciate the great honor the Academy is bestowing upon me with this Founders Award. I am glad to receive it because I feel that by honoring me, you are honoring the fields of biomechanics and aeroelasticity and all my colleagues working in these fields. In front of my colleagues and your distinguished presence, I am filled with a deep sense of humility.

Dr. Brenner, I thank you for your most kind introduction.

I wish to thank my nominators and the members of the Awards Committee for their kindness and generosity. I thank many of my life-long friends, especially Drs Shu Chien, Van Mow, Savio Woo, Bob Nerem, Sidney Sobin, Mike Yen, Che Min Cheng, Shu Qian Liu, and Wei Huang; and my deceased mentor Ernie Sechler, and my friend Chia Shun Yih. To my wife Luna, my son Conrad, my daughter Brenda, my son-in-law Ken, and my grandson Nick, who are here, I give you my love and thanks! I wish my parents could be here to receive my thanks.

I would like to say a few words about my field, biomechanics, how I got there, as well as my perspective today.

I spent the first twenty-four years of my working life first in China, then in the California Institute of Technology in Pasadena, California. My early research was on the dynamics of the airplane in turbulent weather. Combining solid mechanics with fluid mechanics, we call that kind of study the theory of aeroelasticity. Later, I focused on aircraft and spaceship safety, performance and design. In 1958, however, I took a sabbatical leave from Caltech with a Guggenheim Fellowship and went to Germany. There I had time to think about problems other than aeronautics. I became interested in the mechanics of the eye because my mother was suffering from glaucoma. I studied the medical literature, but found it avoids mechanics. Gradually, I was convinced that the understanding of the function of our bodies could be improved if the roles played by forces and motion and stress and strain were analyzed as thoroughly as we do for airplanes.

Upon returning to Caltech, I began to work on blood cells, blood vessels, and microcirculation. At that time, there was a mystery in physiology. Our smallest blood vessels, with walls of thickness about one tenth of our hair was found to be the most rigid of all blood vessels. I solved the mystery by pointing out that the surrounding tissues support these vessels. From this came Fung's tunnel theory of the smallest blood vessels. In the meantime, I predicted that the smallest blood vessels in the lung are the softest of all blood vessels because they have no neighboring tissue to support them. That prediction turned out to be true also. Then I got a theory to explain why our red blood cells are so strong. Billions of these little cells circulate through our smallest blood vessels whose diameters are about the same as that of the cell. Imagine yourself swimming in a tunnel so tight that both of your shoulders touch the wall, and swimming fast unceasingly for 120 days! These little red blood cells survive such gruesome condition! What's the secret? I found the answer, it's their biconcave shape like a donut without a hole. This shape guarantees that the stress in their wall to be zero. So the red cells have a geometrical design which guarantees stress free in life. This reminds me of Taoism in China; the soft wins over the hard, feminism wins over machismo!

In 1965, I published a paper to theorize that if we know the structure and mechanical properties of the materials of a living organ, then by the principles of physics we should be able to predict the functions of that organ. This was a vision I was willing to work for. I decided to give up my first love of aeronautics and resign my professorship at the California Institute of Technology. This decision was very difficult for me because I loved that institution. But I had fallen in love with biomechanics. In 1966, I left Caltech and moved to the University of California, San Diego to initiate a B.S., M.S., and Ph.D. program on Bioengineering. On research, I decided to clarify the blood circulation in the lung. I formulated a sheet-flow theory. To fill in all the experimental details, I worked with my friends Sid Sobin and Mike Yen and many students on the anatomy, histology, microscopy, design and construction of new instruments, testing, theorizing, and calculating. We finished the first round of the lung work in 12 years. It was a fun filled period. We found new things right and left. All together, we published about 100 papers on the lung, each clarifying a piece of the puzzle. Toward the end, all ad hoc hypotheses were removed, our sheet-flow theory was established, and the agreement between theory and experiment was gratifying.

Following the lung work, we looked into the heart, the intestines, the ureter, the tissue remodeling under stress, the problem of high blood pressure etc. The field is so rich that in every direction we looked there were interesting fruits to be picked. But the most remarkable thing is that the whole field is now in full bloom. What was vision to me earlier is now a common sense. Now the field has many, many experts, working on many, many fronts. The scouting boats have been replaced by big ships. The water level is very high; and the explorers are diving to great depth. A field which was dominated by continuum mechanics before is now working on molecular mechanics. Nevertheless, the aim of biomechanics remains the same. The aim is to clarify the role of forces in relating structure to function in biology.

Thus, molecular biomechanics connects the molecular structure to molecular function. The cell membrane biomechanics connects the membrane structure to the membrane functions. Similarly, cell biomechanics links cell structure to cell function, tissue biomechanics links tissue structure to tissue function, organ biomechanics connects organ structure to organ function, whole body mechanics links up body structure to body function. Hence, biomechanics is the middle name of biological structure and function. Bioengineers use these mechanics to invent ways to help the biologists, the physicians, and the patients.

But becoming important is not the whole story. To me and many of my colleagues, the factors of personal interest and satisfaction are significant. Perhaps because the field of bioengineering is so large, and its maturity is still far away, it is easy to feel that you are still a pioneer making personal discoveries. I am sure that the sum total of our effort will benefit mankind. Thank you, very much