According to available research, how can art therapy be applied as an effective social work intervention, working with children who have been abused?

You are welcome.

That is new to me, thanks so much.

Approaches that focus on the trauma itself or the relationships are found to be more effective than more open-ended therapies such as art therapy or play therapy. Expressive therapies are incorporated into some broader modalities. If your goal is to learn how to help abused children, I recommend that you learn about Trauma-focused Therapies (e.g., TF-CBT).