How to select a PhD topic in Mechanical Engineering?

Choosing the right PhD topic in Mechanical Engineering is crucial as you will spend almost 6 years in the research work. Identify a topic that interests you. You can choose from the current research trends including Artificial Intelligence, Machine Learning, Digital Twins, etc. Check for the research gaps that remain unexplored. Attending conferences to look for unsolved problems. Pick a topic that can be challenged academically and has a fair share of application to it. Discuss with the supervisor for advice and doubts.