You can define the element size along selected edges by entering the number of elements to create. To do so, you can choose the ‘Seed Edges’ icon located with the seed tools in the Mesh module toolbox. Reminded that if the model hasn’t any edge on thickness, you should partition it using one of the partitioning methods. For more information about mesh techniques, refer to https://caeassistant.com/product/abaqus-for-beginners-mechanical-engineering-copy/.