This book reports on advances in applied mechanics research and applications. It covers methods, modeling, and simulation tools for products design, material behavior analysis, and for optimizing production processes. It also reports on cutting-edge techniques to increase performance of mechanical systems and foster energy transition. The book gathers selected contributions to the 12th International Congress for Applied Mechanics (JET'2024), held on November 13-15, 2024, in Marrakech, Morocco. The congress was organized by the Franco-Maghreb Association of Mechanics and Materials (AF3M) with the close collaboration of the Moroccan Society of Mechanical Sciences (SMSM). Overall, this book gives a special emphasis to theoretical and practical advances in mechanics, supporting sustainable and environmentally friendly development.