In 1941, Ras and his bride, Shirley Wilson, whom he met at Stanford, decided to return to England, whereupon he worked at the Ordnance Board and later in the Armament Research Department. In 1944, he was elected a fellow of his College at Cambridge, Gonville and Caius, and in 1945, he received an M.A. from Cambridge. By this time he was contemplating an academic career but decided he should have some experience in engineering practice first. In 1946, he was offered the position of assistant director in charge of the Technical Section, Production Department in the newly established Department of Atomic Energy, where he was involved in the initial designs for the British atomic energy program. However, the next phase—power production—would have taken another five years, so Ras decided it was time to begin his academic career in earnest. He returned to the United State for the second time in 1948 to take up a permanent position as associate professor at Brown University. He remained at Brown until 1962, when he accepted a position at Stanford.
During World War II, the U.S. Navy was keenly interested in impact deformation and the penetration mechanics of projectiles. The Office of Naval Research (ONR) brought a world authority on plasticity, Professor William Prager, to Brown University to conduct research and provided substantial financial support for the establishment of the Graduate Division of Applied Mathematics; Ras was recruited as an associate professor. Soon he was promoted to professor and later elected chairman of the division, a position he held for five years.
In time, several generations of graduate students were brought into the field of plasticity (the study of the consequences of loading materials beyond their elastic range), and these students gradually spread to other leading universities. The year of Ras’s retirement from Stanford, his former students and colleagues presented him with a commemorative volume, Topics in Plasticity, edited by Wei H. Yang (AM Press, Ann Arbor, Michigan), that includes articles and encomiums describing Ras’s path-finding contributions in mechanics and engineering science.