Integrate, articulate, concatenate are comparable when they mean to bring or join together a number of distinct things so that they move, operate, or function as a unit.
The implications of these senses are probably more often found in the participial adjectives integrated, articulated, concatenated and in the derived nouns integration, articulation, concatenation than in the finite verbs.
Integrate implies that the things (as parts, elements, factors, or details) combined are brought into such intimate connection with each other that a perfect whole results. Usually it suggests a complete fusion or coalescence of particulars with loss therefore of their separate identities.
Articulate also implies as its result a perfect whole, but it differs from integrate in implying no loss of identity or of distinctness of the things (as parts, branches, and departments) combined and in suggesting a connection between them that is found in its perfection in the skeletons of vertebrate animals. For articulate implies organization in which each part fits into another in a manner comparable to the fitting into each other of two bones at a movable joint and a structure is built up that functions as a whole yet without loss of flexibility or distinctness in any of its component units or without any conflict between them.
Concatenate suggests neither fusion nor organization but a linking together of smaller units until figuratively a powerful chain is forged. It implies addition of one thing to another with cumulative effect.