Opening .inp file in Abaqus/CAE

Why do we need to open inp file in Abaqus (Abaqus import inp file)?

An Abaqus input file (inp file) is a text-based file that contains the instructions, data, and parameters needed to define and run an Abaqus simulation. The Abaqus solvers, in reality, read the input file for an analysis. We’ll go through what an Abaqus input file is and how to run one in Abaqus.

The Abaqus input file has a specified format that adheres to a set of syntax constraints. The Abaqus inp file can be generated using a text editor and the user’s scripting abilities, or it can be generated using Abaqus’ graphical user interface (GUI). The inp file operates using a set of keywords (commands) created specifically for Abaqus, each of which serves a specific purpose in defining the simulation model, material properties, boundary conditions, analysis type, and other relevant parameters. The inp file structure can be divided into several sections.

When you open an input file in Abaqus, you are instructing the software to read and interpret the contents of the input file. You can see the model’s geometry, but you can’t change it. In fact, when you open an inp file, the model has orphan meshes, so you cannot change it. In other words, you can change anything but the model’s geometry. If you need to change the model’s geometry, you need to have access to the “jnl” or “cae” files. The “jnl” file allows you to modify the model’s geometry, boundary conditions, and many other things. Moreover, you can modify it to automate the simulation for several analyses to see, for example, changes in the stresses when some dimensions of the model change. Interesting, right? If you want to know more, about “jnl” files, see this Question, or if you need to know how to do the automation, see Workshop 2 of the Python scripting in the Abaqus section in the Abaqus Free course.

Opening the Abaqus input file also allows you to make changes to the model or analysis settings, as needed. For example, you may want to modify the boundary conditions or switch to a different element type. By opening the input file in Abaqus, you can make these changes directly in the input file and then re-run the analysis.

How to open the Abaqus input file?

Let’s see how we can open an Abaqus input file (Abaqus import inp file).

You can open .inp file in Abaqus to have a sense of geometry, materials, etc. This is called importing. From the main menu bar, go to File > Import > Model. In the pop up window that appears, filter files as .inp file. Browse your .inp file and press OK:

This will allow you to make changes to the model in Abaqus/CAE, though you lose the CAD (3D geometry) in this case. You can only make changes based on the mesh using this method.
Remember that importing just involves commands that Abaqus/CAE supports. There are many only Keyword commands that are not supported yet in CAE environment. If you run the input file in this manner, you will almost certainly meet an error or obtain incorrect results, especially if you are using inp files from the Abaqus manual. Why? Because some commands and keywords may not be properly entered into the Abaqus GUI, or the GUI may not support the keywords! Yes, some keywords lack a graphical interface, however these commands and keywords are required by some simulations. As a result, in these simulations, you must manually build the input file, insert the needed keywords, and execute the input file.

See also this Q&A:
How can I run .inp files in Abaqus to view the results?

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