As Teacher and Mentor

Lloyd Hamilton Donnell was born on May 25, 1895, in Kents Hill, Maine, the son of Albert Webb Donnell, a teacher, and Annie Morrell Hamilton Donnell, an author. After completing his regular education, he earned his BSc in Mechanical Engineering from the University of Michigan in 1915. Following his graduation, Donnell began his teaching career at the University of Michigan and continued his studies there, obtaining his PhD under Stephen Timoshenko in 1930.

After obtaining his PhD, from 1930 to 1933, Donnell served as a research assistant at the Aeronautical Laboratory of Caltech, working under Theodore von Kármán. From 1933 to 1939, he then took on the role of engineer at the Goodyear Zeppelin Company, where his work focused on the design of airships.

In 1939, Donnell transitioned to academia, joining the Illinois Institute of Technology faculty as Professor of Mechanical Engineering, a position he held until his retirement in 1962. His career continued to flourish post-retirement as he took on a role at Stanford University and later, in 1974, served as a guest professor at the University of Houston.

Donnell's contributions to the field of engineering mechanics, especially his stress-analysis research into cylindrical shells, significantly advanced the development of monocoque bodies for automobiles and planes. His studies extended into dynamics, elasticity, instability, and wave propagation, earning him international recognition as an expert in shell analysis and thin-shell structure.

Throughout his illustrious career, Donnell was honored with several prestigious awards. He was the recipient of the Worcester Reed Warner Medal from the American Society of Mechanical Engineers (ASME) in 1960, the Theodore von Karman Medal in 1968, and the ASME Medal in 1969. Additionally, the Illinois Institute of Technology awarded him an honorary doctorate, and he was the founding editor of the engineering journal Applied Mechanics Reviews.

Lloyd Hamilton Donnell passed away on November 7, 1997, leaving behind a legacy as a pioneering mechanical engineer and educator.

Max Mark Frocht, a celebrated Polish-American engineer and educator, made significant contributions to the field of engineering mechanics, particularly through his expertise in photoelasticity. After moving from Congress Poland to the United States in 1912, Frocht initially settled in Detroit, where he worked as a machinist and tool maker. Pursuing higher education, he earned a B.S. in Mechanical Engineering from the University of Michigan in 1920, followed by an M.S. in Physics from the University of Pittsburgh in 1925, and culminated his academic pursuits with a Ph.D. from the University of Michigan in 1931 under the guidance of Stephen Timoshenko.

Frocht's academic career included a tenure at the Carnegie Institute of Technology as an instructor and later as a professor after completing his Ph.D. In 1946, he joined the Illinois Institute of Technology's mechanical engineering faculty, where he served until 1960, subsequently taking the helm of the university's Laboratory for Experimental Stress Analysis. During this period, Frocht became a pivotal figure in the field of photoelasticity, authoring a two-volume classic work that was translated into Russian, Spanish, and Chinese, reflecting its global impact.

An active and early member of the Society for Experimental Stress Analysis (now the Society for Experimental Mechanics), Frocht's career was marked by a productive rivalry with fellow faculty member and SESA member August J. Durelli, which contributed significantly to the advancement of photoelastic methods. Despite their rivalry, Frocht's retirement led to the leadership of the IIT Laboratory for Experimental Stress Analysis passing to James W. Dally and Cesar Sciammarella, both students of Durelli.

In recognition of his contributions, Frocht was named the third Honorary Member of SESA in 1959, a title he held until his passing in 1974. Notably, he is the only Honorary Member of the society not to have been named a Fellow, as the rank of Fellow was introduced in 1975, the year after his death. The Society for Experimental Mechanics established the M.M. Frocht Award in 1967 to honor his legacy, recognizing outstanding achievements in experimental mechanics education. Frocht was the inaugural recipient of this award in 1968, underscoring his profound impact as an educator in the field.

Source: Society for Experimental Mechanics

James Norman Goodier, born on October 17, 1905, in Preston, Lancashire, England, was a distinguished professor at Stanford University, celebrated for his significant contributions to the study of elasticity and plastic deformation. Educated in engineering at Cambridge University, Goodier furthered his academic pursuits in the United States, thanks to a Commonwealth Fund Fellowship. This opportunity led him to the University of Michigan, where he completed his Ph.D. in 1931 under the mentorship of Stephen Timoshenko. His doctoral work focused on the Compression of Rectangular Blocks and the Bending of Beams by Nonlinear Distributions of Bending Forces. Following Timoshenko's move to Stanford University in 1936, Goodier later joined him there, ultimately taking over his position after Timshenko retired.

Goodier's scholarly work includes co-authoring two seminal texts in his field: "Theory of Elasticity" with Timoshenko in 1951 and "Elasticity and Plasticity" with P. G. Hodge, Jr., in 1958. His excellence in the field was recognized in 1961 when he received the Timoshenko Medal from the American Society of Mechanical Engineers. Between 1945 and 1946, he served as the chairman of the Applied Mechanics Division of the same society and was named a Fellow in 1964. Over his career, Goodier guided over fifty doctoral candidates, among them notable scholars like George F. Carrier and Nils Otto Myklestad. He passed away on November 5, 1969.

Source: Stanford Historical Society 

Miklós Imre Hetényi, born on November 5, 1906, was a prominent Hungarian-American engineer renowned for his academic and professional contributions. Serving as a professor at Stanford University, Hetényi played several key roles in the Society for Experimental Stress Analysis (now known as the Society for Experimental Mechanics), notably as its second President from 1944 to 1945. He was the son of Géza Hetényi and Etelka Jakab (1864–1956) and passed away while working on a book about structural mechanics at his Stanford home on October 31, 1984.

Hetényi completed his civil engineering degree at the Budapest University of Technology and Economics in 1931, followed by graduate studies under Harold M. Westerguard at the University of Illinois between 1934 and 1935. He earned a Ph.D. in mechanical engineering from the University of Michigan in 1936, under the mentorship of Stephen Timoshenko, becoming one of Timoshenko's esteemed students. His experimental collaborations with Ray Mindlin and Dan Drucker are particularly noted.

After completing his Ph.D., Hetényi joined Westinghouse Electric Corporation's research laboratories, where he worked until 1946. He then transitioned to academia as a professor at Northwestern University's Institute of Technology, before moving to Stanford University in 1962. At Stanford, he established the Experimental Stress Analysis Laboratory and led the Applied Mechanics Department from 1965 to 1969 until his retirement in 1972. His contributions to mechanics, especially in three-dimensional photoelasticity, the Reduction Method, and the Method of Initial Parameters, are significant.

As a foundational member of the Society for Experimental Mechanics, along with Charles Lipson, Raymond D. Mindlin, and William M. Murray, Hetényi's legacy includes the Hetényi Award, established in 1967 for the best research paper in Experimental Mechanics. He was honored with the Murray Lecture in 1954 and became the society's second Honorary Member in 1956, a title he held for the rest of his life. He was among the first to be named an SEM Fellow in 1975, and he also played a significant role in the American Society of Mechanical Engineering, where he chaired the Applied Mechanics Division in 1957 and was named an Honorary Member in 1973. Hetényi received honorary degrees from the University of Technical Sciences in Budapest and the University of Glasgow, marking a career distinguished by numerous accolades and recognitions, including the SEM Murray Lecture and Award, the SEM/SESA Founder Award, and the ASME Honorary Member designation.

Source: Mechanics IUTAM USNC/TAM: A History of People, Events, and Communities

Nicholas J. Hoff, a trailblazer in the field of aeronautics and astronautics and a distinguished professor emeritus at Stanford University, passed away at his Stanford campus home on August 4, 1997. Born in the small Hungarian town of Magyaróvár on January 3, 1906, Hoff's early life was marked by a move to Budapest at the outbreak of World War I, where his father, a successful dentist, relocated the family. It was in Budapest that Hoff completed his secondary education at the Evangelikus Gimnazium, a school also attended by notable figures such as Eugene Wigner, Leo Szilard, and John von Neumann.

Originally an accomplished violinist contemplating a career in music, Hoff's passion for sports, particularly skiing and gliding, steered him towards engineering. He pursued this interest at the Swiss Federal Institute of Technology in Zurich, studying under Aurel Stodola and graduating with an engineering degree in 1928. Hoff then contributed to Hungarian aviation, designing training planes and fighters for the Weiss Manfred Aeroplane and Motor Works of Budapest from 1929 to 1939.

Seeking to further his expertise, Hoff reached out to Stephen P. Timoshenko and moved to the United States in 1938 to study solid mechanics at Stanford University, where he earned his Ph.D. in 1942. World War II disrupted his plans to return to Hungary, leading him to accept a teaching position at the Polytechnic Institute of Brooklyn. There, Hoff made significant contributions to the understanding of the stability of monocoque-thin-walled and sandwich structures, preventing buckling in aircraft structures.

In 1957, Hoff was invited by Provost Fred Terman to Stanford University to establish a department of aeronautical engineering, which quickly became a leading center in its field under his guidance. His research on the stability of thin-walled structures culminated in the publication of his acclaimed text, "Analysis of Structures," in 1966. Even after retiring in 1971, Hoff remained active in academia, serving as a visiting professor and lecturing internationally.

Hoff's contributions to engineering were recognized with numerous prestigious awards and honors, including the Worcester Reed Warner Medal (1967), the Theodore von Karman Medal (1972), the ASME Medal (1974), and the Daniel Guggenheim Medal (1983). Elected to the U.S. National Academy of Engineering and a Fellow of the Society for Experimental Mechanics in 1987, Hoff was celebrated not only in the United States but also in Hungary, France, and internationally, receiving memberships in multiple academies of science and engineering societies. His legacy includes not just his scientific contributions but also his role in shaping future generations of engineers and scholars.

Nicholas J. Hoff is survived by his wife, Ruth Kleczewski Hoff, daughter-in-law Karen Brandt of Palo Alto, and brother George Hoff of Santa Barbara, leaving behind a lasting impact on the fields of aeronautics and astronautics.

Source: National Academy of Engineering 

Egor Paul Popov was born on February 6, 1913, in Kiev, then within the Russian Empire. His early life was marked by the upheaval of the Bolshevik Revolution in 1921, which led his family to flee first to Manchuria and then to Shanghai before finally emigrating to the United States in 1927. Settling in San Francisco, Popov embarked on his academic journey at the University of California, Berkeley, in 1929, studying civil engineering and graduating with honors in 1933. His academic excellence earned him scholarships for graduate studies at the Massachusetts Institute of Technology, where he completed his MS in civil engineering in 1934, and then at the California Institute of Technology, where he moved in pursuit of his doctoral degree.

During his time at Caltech from 1935 to 1937, Popov studied under Theodore von Kármán and taught courses, but was advised to seek mentorship from Stephen Timoshenko at Stanford University due to his mathematical approach to engineering. Instead of immediately transitioning to Stanford, Popov spent eight years working in structural analysis and design across southern California, gaining extensive practical experience. This period included constructing his own house in San Gabriel, using his credentials as a mechanical engineer, a civil engineer with structural authority, and a general contractor.

In 1945, Popov reached out to Timoshenko, expressing his desire to pursue a dissertation in civil engineering at Stanford University, which accepted his graduate coursework from MIT and Caltech. Popov completed his PhD under Timoshenko's guidance in the summer of 1946 and joined UC Berkeley as an assistant professor. There, he played a pivotal role in establishing a PhD program in civil engineering, mentoring 34 PhD students, including Mihran Agbabian, the program's first PhD graduate in 1951.

Popov's dissatisfaction with existing engineering textbooks led him to publish "Mechanics of Materials" in 1952, which became widely adopted in engineering programs both in the U.S. and internationally. In 1958, he became the first chair of the new division for structural engineering and structural mechanics at UC Berkeley, and also directed the Structural Engineering Laboratories.

Throughout the 1960s and 70s, Popov contributed significantly to the field of structural mechanics, developing theoretical methods for predicting buckling failures in shell structures, collaborating with NASA on solving buckling problems for its vacuum chamber, and publishing on nonlinear mechanics. His research extended to improving seismic safety through the use of friction devices and contributing to the design of the Alaska pipeline and the San Francisco–Oakland Bay Bridge.

Popov's involvement with the Structural Engineers Association of Northern California led to his presidency from 1983 to 1984. His work on eccentrically braced frames (EBFs) with PhD student Charles Roeder in the 1970s improved seismic design practices. He continued to innovate in structural engineering, including participating in full-scale testing of EBF connections in Japan, which informed changes in building codes for seismic safety.

After retiring in 1983, Popov was named Professor of the Graduate School at UC Berkeley, allowing him to continue his research. He published "Engineering Mechanics of Solids" in 1990, further cementing his legacy in the field. Popov's dedication to teaching and research was recognized through numerous awards, including UC Berkeley’s Distinguished Teaching Award in 1977, the Berkeley Citation in 1983, and several prestigious awards from engineering societies. He was elected to the National Academy of Engineering in 1976 and posthumously recognized as Top Seismic Engineer of the 20th Century by the Applied Technology Council in 2006.

Popov's personal life was equally rich, with a strong marriage to Irene, whom he married in 1939. Irene supported him significantly, typing his manuscripts and managing his handwritten equations. Together, they raised two successful children, Kathy and Alex. Egor Popov passed away on April 19, 2001, in Berkeley, California, leaving behind a profound legacy in both his professional and personal lives. He was survived by his children, six grandchildren, and eleven great-grandchildren, a number that has since grown to sixteen.

Source: National Academy of Engineering