William Prager, (before 1940) Willy Prager, (May 23, 1903 in Karlsruhe – March 17, 1980 in Zurich) was a German-born US applied mathematician. In the field of mechanics he is well known for the Drucker–Prager yield criterion.
Willy Prager studied civil engineering at the Technische Universität Darmstadt and received his diploma in 1925. He received his doctorate in 1926 and worked as a research assistant in the field of mechanics from 1925 to 1929. From 1927 to 1929 he habilitated. He was a deputy director at University of Göttingen, professor at Karlsruhe, University of Istanbul, the University of California, San Diego and Brown University, where he advised Bernard Budiansky. Prager was also on a sabbatical at IBM's research lab in Zurich.
- Beitrag zur Kinematik des Raumfachwerks, 1926, dissertation
- "Dynamik der Stabwerke" (with K. Hohenemser), 1933
- "Mechanique des solides isotropes", 1937
- Prager, William; Hodge, Philip G, Jr. (1951). Theory of Perfectly Plastic Solids. John Wiley & Sons. LCCN 51-012695.
- Prager, William (1961). Introduction to Mechanics of Continua. Ginn and Company.
- Speiser, Ambros (1988). "IBM Research Laboratory Zurich: The Early Years". IEEE Annals of the History of Computing. 20. doi:10.1109/85.646205.
- William Prager Medal
- "John Simon Guggenheim Foundation | William Prager". Retrieved 2019-09-16.