This publication contains the selected papers presented at the 12th International Conference on Fracture Fatigue and Wear (FFW 2024) and the 7th International Conference on Numerical Modelling in Engineering (NME 2024), both held on 28-31 July 2024, in Xi'an, Shaanxi, China. The objective of the FFW 2024 conference was to share the results of engineering investigations in fracture mechanics, fatigue of materials, tribology and wear of materials. The articles that were collected cover theoretical and analytical methods, numerical simulations, and experimental techniques for decision-making in the mentioned engineering sphere. The overall objective of the NME 2024 conference was to present the latest achievements in numerical techniques, such as FEM, BEM, IGA, etc., and their applications to a wide range of engineering disciplines. This edition will be helpful to engineers and researchers of many branches of engineering.