Professor Emeritus Isaac M. Daniel Passes Away

Isaac M. Daniel, professor emeritus of civil and environmental engineering and mechanical engineering, passed away September 3, 2026, at age 92. Daniel will be remembered for his role in the development of modern composite-materials engineering and contributions to the literature in his research fields. 

“Isaac Daniel was a truly distinguished scholar whose depth of knowledge in the mechanics of composite materials was second to none,” said Sinan Keten, Jan and Marcia Achenbach Professor and chair of mechanical engineering at the McCormick School of Engineering. “Throughout his long and distinguished service at Northwestern, Professor Daniel inspired generations of students and was a beloved colleague and mentor whose warmth, kindness, and generosity touched all who had the privilege of knowing him.”

Daniel joined the McCormick School of Engineering in 1986 as a professor of theoretical and applied mechanics who had a joint affiliation with the Department of Civil and Environmental Engineering and Department of Mechanical Engineering, transitioning to emeritus status in 2019. Before coming to Northwestern, Daniel worked as a research assistant at the Chicago Bridge and Iron Company, an assistant research engineer at Armour Research Foundation, and as manager of the experimental stress analysis section and science adviser to IIT’s materials and manufacturing technology division. Daniel then served as a professor at the Illinois Institute of Technology (IIT) from 1982 to 1986, Daniel earned his BS (1957), MS (1959), and PhD (1964) in civil engineering from IIT.

At Northwestern, Daniel’s research spanned a wide range of topics in mechanics and materials, with a particular focus on experimental mechanics and composite materials. He studied the processing, characterization, and modeling of polymer-, ceramic-, and metal-matrix composites, as well as nanocomposites and hybrid materials, while also advancing work in fracture and damage mechanics, nondestructive evaluation, and life prediction. He pioneered test methods for characterization of these materials and developed a new failure theory, the Northwestern Theory, a framework for understanding and predicting failure in composite materials subjected to complex stresses.

“Isaac Daniel’s contributions to Northwestern CEE were profound and enduring. He helped establish our department as a leader in mechanics and composite materials, advancing the field through pioneering research while educating generations of engineers,” said Yu (Marco) Nie, Roxelyn and Richard Pepper Family Chair in Civil and Environmental Engineering. “What is equally meaningful is how his former students remember him—not only as an excellent teacher, but as a caring and generous mentor. We are deeply grateful for his legacy and will miss him greatly.”

From 1996 to 2009, Daniel directed Northwestern’s Theoretical and Applied Mechanics program. Beginning in 1997, he also directed the Center for Intelligent Processing of Composites, and in 1998 he was named a Walter P. Murphy professor. A holder of four patents, Daniel was a prolific writer of academic books and articles. He was the author of more than 500 publications and contributed numerous book chapters. Perhaps his best-known work was Engineering Mechanics of Composite Materials (Oxford University Press, 1994). Written with Ori Ishai, a professor at Technion Israel Institute of Technology, the widely used textbook brought together theory, experimentation, design, and optimization and became an important reference for engineers.

“My students who took his classes on composite materials always praised him as an excellent teacher and very caring individual,” said Surendra Shah, Walter P. Murphy Emeritus Professor of Civil and Environmental Engineering.

His professional achievements earned widespread recognition from peers. Daniel was elected a fellow of the Society for Experimental Mechanics, the American Society of Mechanical Engineers, the American Society for Composites, and the American Academy of Mechanics. Among his many honors were the Society for Experimental Mechanics' Hetényi, Lazan, Murray, Frocht, Theocaris, and Taylor awards, as well as its Medal of Excellence in Composite Materials. The Society further recognized his contributions by naming him an Honorary Member in 2007. A symposium held in his honor in 2002 reflected the respect he commanded throughout the field. 

Services were held.