I have created a matrix (cube) and inclusion (sphere), 20% volume fractions of the matrix. This resulted in around 1000 spheres; hence, it cannot be successful; Abaqus shows "merge operation was unsuccessful." Then I attempt to create some interaction between them to avoid merging operations. So, my question: is there anyways to create interaction between them replacing my merge operation? If so, how to create them? Putting simply, how to create interaction between inclusion with the matrix in general?