I can strongly recommend learning FEA or CFD. FEM is a numerical technique that allows simulation of solid and fluid behavior. FEM is generally not often used in fluid simulation since the method can result in unstable solutions due to the presence of convective terms. FEM is more commonly used for simulation of structural (or solid) behavior. For fluid simulations, Finite Volume Method or Finite Different Method is more often employed.
These days there are also several MOOC courses that help learning them online. In addition, one does not have to pay anymore to obtain these softwares. There are several open-source CFD and FEA softwares that one can use to learn these.
Pre-requisites for FEM can be:
- Tensor calculus
- Strength of materials
- Basic solid mechanics
For a general knowledge of FEM including basic to detailed discussion, I can suggest the three-volume FEM book by O C Zienkiewicz & R L Taylor.
Volume 01: The Finite Element Method: Its Basis and Fundamentals
Volume 02: The Finite Element Method For Solid and Structural Mechanics
Volume 03: The Finite Element Method for Fluid Dynamics
If you are looking at Nonlinear Finite Element Method, I can strongly recommend the book “Nonlinear Finite Element Methods” by Peter Wriggers.
For books on computational contact mechanics, I can strongly recommend
Introductory text: Introduction to Computational Contact Mechanics: A Geometrical Approach by Alexander Konyukhov, Ridvan Izi
More advanced text: Computational Contact Mechanics by Peter Wriggers
Most of these books also address the required pre-requisites.
Alongside above, I can suggest getting hands-on experience. I can suggest simulation software like SimScale which is cloud-based and can be accessed through a browser. They presently allow for solid, fluid and particle simulations. They also offer a free version where one can get upto 3000 hours for computing. For the free version, the projects created are publicly available. However, if one would like to keep your project private, a professional version is also available. There is also a two-week free trial for the professional version of the platform. The SimScale tutorials and materials provides easy to understand materials to help with usage of SimScale platform. In addition, you can explore the public projects database, where there are loads of projects already available. You can also write on their forum for help and assistance and they are quite active there too.
Learning one software can come in extremely handy. Shifting between platforms is just a matter of adaptability. I myself know several people who had written that they know FEA on their CVs and were asked about that in the interview. Doing well on these ensured a good job!