The requirements of Zheng Da's Ph.D. in Mechanical Engineering include: completing academic requirements, completing postgraduate thesis, defending thesis and publishing thesis, and having a certain level of foreign language and scientific research ability.

1. Completion of academic requirements: Students need to complete the required credit requirements and obtain qualified grades, including passing various examinations and assessments.

2. Postgraduate thesis completion: Students need to complete and submit doctoral thesis within the specified time.

3. Thesis defense: students need to pass the doctoral thesis defense and get the approval of the defense Committee.

4. Publish papers: Students need to publish research results in authoritative academic journals or conferences at home and abroad.

5. Have a certain level of foreign language: students need to pass the national English proficiency test and obtain a certain foreign language proficiency certificate.

6. Have certain scientific research ability: Students need to have certain scientific research ability, including the ability to think independently, conduct experiments independently and solve scientific research problems.