Theoretical grounds for the use of metal multilayer structures in the manufacturing and repair of agricultural machinery

Fatigue failure is the most common type of failure of agricultural machinery parts. When designing parts of agricultural machinery, some scientists suggest using metal multilayer structures. In order to justify the use of metal multilayer structures, as well as to determine the possible ways to increase their fatigue strength, the authors conducted an analytical review of scientific literature on fatigue failure of metal multilayer structures. They considered some specific features of the implementation of the additive technology of sheet lamination using the case of manufacturing agricultural machinery parts. As a result, they have determined the influence of thickness, number and properties of layers and interlayer boundaries on the fatigue strength of metal samples with a multilayer structure, obtained using the conventional technologies by explosion welding or hot packet rolling, and parts with similar multilayer structure, obtained using the additive sheet lamination technology. The authors considered an example of fatigue failure of a part with mechanical and adhesive bonding of layers. Based on the analysis results, they proposed technical approaches to the additive manufacturing of metal parts with a multilayer structure, providing an increase in their fatigue resistance. They have offered recommendations on the selection of initial metal sheets for cutting out sheet patterns, on determining thickness and total number of the patterns, on making holes in the patterns serving to connect them with mechanical fasteners, as well as to reduce weight to ensure topological optimization. The task of further research of strength properties of metal multilayer structures is the experimental determination of the relationship type between the fatigue failure of a part and the number of its composition layers.