Theodore H. H. Pian; taught aeronautics, astronautics at MIT

Just as important to him was the need that he and his wife, Rulan, a Harvard professor emerita of East Asian studies and music, shared to open their Cambridge home as a gathering place for other Chinese immigrants.

“They really helped a lot of Chinese-American students,’’ said his daughter, Canta of Washington, D.C. “They mentored, they entertained, they had students living with them . . . They really helped spawn a lot of the subsequent groups for Asian students in the Cambridge area.’’

Despite retiring in 1990, Dr. Pian continued to give Chinese graduate students advice or a place to go for Thanksgiving dinner, until about eight years ago, when his health declined.

A retired aeronautics and astronautics professor and prominent researcher in the field of finite element methods, Dr. Pian died of natural causes June 20 in his Cambridge home. He was 90.

A native of Shanghai, China, Theodore Hsueh Huang Pian grew up in Pianjin and earned a bachelor’s degree in engineering in 1940 at Tsing Hua University in Beijing - though engineering hadn’t been his first area of interest.

“He had wanted to major in architecture, but the Chinese knew that engineering was the key to the future of China,’’ his daughter said. “So he took the engineering exams. He was a stellar student. It wasn’t his first choice, but he was obviously a very creative person, and he applied that in his engineering career.’’

After graduating, Dr. Pian worked in Chinese aircraft manufacturing on the Burma Road during World War II before coming to the United States in 1943.

In 1944, he earned a master’s degree in aeronautics and astronautics from the Massachusetts Institute of Technology and briefly worked as a stress analyst for Curtiss Airplane Division in Buffalo. The same year, he joined the Marines in anticipation of serving as a translator for the American troops in the event they returned to China to liberate the country from Japanese control. The war ended in 1945 before Dr. Pian could be deployed.

In 1945, he married Rulan Chao, a Harvard graduate student he’d met while at MIT. Dr. Pian returned to MIT that year to work on his doctorate in aeronautics and astronautics, which was awarded in 1948.

Remaining at MIT, Dr. Pian rose from teaching assistant and research associate in the department of aeronautics and astronautics to full professor in 1966.

Former colleagues said Dr. Pian focused his research at MIT on the structural analysis of aircraft, including elastic-plastic creep, shear-lag, stresses, and the bending of plates. Many techniques he helped to develop are still in use.

“From my perspective, I would characterize Ted as being one of the pioneers in that world and of setting the foundations for much of structural analysis, particularly in aerospace, but in several industries,’’ said Paul Lagace, a professor in MIT’s aeronautics and astronautics department.

Pin Tong, a bioengineering professor at the University of California, San Diego, met Dr. Pian in 1966, when Dr. Pian was on sabbatical at the California Institute of Technology. Dr. Pian recruited Tong, a recent California Institute of Technology graduate, to MIT and became his mentor.

“He was a very kind and gentle person,’’ Tong said. “A very low-key kind of person. Very considerate, kind, and thoughtful.’’

During his career, Dr. Pian lectured at 46 universities in the United States, as well as at 55 other universities in countries including China, Japan, India, Israel, Germany, Britain, and Canada. He also served as a visiting professor at 10 foreign universities and was named an honorary professor at several engineering schools and aeronautical institutes in China, his daughter said.

In 1974, Dr. Pian received the von Karman Memorial Prize for outstanding contributions to aerospace structural-material technology, one of many honors he modestly accepted during his career, said his son-in-law, Michael Lent of Washington, D.C.

“He was extremely humble,’’ said Lent, who recently came across his father-in-law’s collection of plaques and medals, which were tucked away in a basement. “A lot of people would have built a glory wall and hung all this stuff, but he would be the last person to do that.’’

By the time he retired, Dr. Pian had authored more than 200 professional papers and wrote or edited several books in the field of finite element methods. He was a member of numerous national and international professional societies, including the National Academy of Engineering and the American Institute of Aeronautics and Astronautics.

In retirement, he and his wife traveled the world, frequently to China and Taiwan.

In addition to his wife and daughter, Dr. Pian leaves a granddaughter. A memorial service will be held at a later date.