We have learned with sadness of the death of Nguyen Quoc Son, former research director of the CNRS who carried out his activity within the Laboratory of solid mechanics.
►In Memoriam of Nguyen Quoc Son (1944 – 2021)
Nguyen Quoc Son (1944-2021), called Son by his colleagues and pupils, was a pupil of the Polytechnic School (X64) and did the demonstration school at the National School of Bridges and Roads. After a short stint in industry, he entered the CNRS in 1969 and obtained his Doctor of Science in 1973, at the laboratory of Professor Jean Mandel (X26) under the supervision of Professor Dragos Radenkovic. His work was honored in 1978 by the Arthur Dufay Prize from the Académie des Sciences in 1988 by the Silver Medal from the CNRS and in 2007 by the Grand Prix Jaffé from the Académie des Sciences.
Son initiated with his fine mind and his deep analyzes many of the problems and methods of solution in solid mechanics. His heirs were numerous and the French school of Mechanics of Materials made intensive use of his ideas. It was he who had proposed in 1975, with Bernard Halphen the concept of generalized standard material1, then initiated the algorithms with double plasticity projection2 which are at the base of the major calculation codes today, the study of stability for dissipative materials, a stationary algorithm for mobile coordinate system4 problems, etc. At the beginning of April he had published another paper and we were all waiting to find an opportunity to discuss it in detail.
Colleagues, friends and students also appreciated him for his great kindness, his permanent smile and for his absolute discretion which sometimes deprived him of a recognition that should have been greater.
 Halphen, B., et Nguyen, Q.S. "Sur les matériaux standard généralisés." Journal de mécanique 14 (1975): 39-63.
 Nguyen, Q.S., “On the elastic-plastic initial boundary value problem and its numerical integration,” International Journal for Numerical Methods in Engineering 11 (1977), 817–832.
 Nguyen, Q.S. Stability and nonlinear solid mechanics. Wiley, 2000.
 Nguyen, Q.S. and Rahimian. M. (1981) Mouvement permanent d’une fissure en milieu élastoplastique. J. de Mécanique Appliqué, 5 (1981), 120.